1. What is the percent by volume of a solution formed by mixing 349 mL of isopropanol with 380mL of water?
2. What is the mass of a solute in a solution with 65% (m/m) of a solute and a mass of the solution is 327. 0g?
3. Calculate the molarity of 171g of KBr dissolved in 829. 0 mL pure water
The percent by volume of a solution formed by mixing 349 mL of isopropanol with 380mL of water. The mass of a solute in a solution with 65% (m/m) of a solute and a mass of the solution is 327g. The molarity of 171g of KBr dissolved in 829. 0 mL pure water
1. The percent by volume of the solution formed by mixing 349 mL of isopropanol and 380 mL of water is 52.2% and 47.8%.
To find the percent by volume of the solution, we need to add the volumes of the two components and then calculate the percentage of each component in the total volume:
Total volume = [tex]349 mL + 380 mL = 729 mL[/tex]
Percent by volume of isopropanol = [tex](349 mL / 729 mL) * 100percent = 47.8 percent[/tex]
% by volume of water = [tex](380 mL / 729 mL) * 100 percent = 52.2percent[/tex]
Therefore, the solution contains 47.8% (v/v) of isopropanol and 52.2% (v/v) of water.
2. The mass of the solute in a solution with 65% (m/m) of a solute and a mass of the solution of 327.0 g is 212.55 g.
We are given the mass percent (m/m) of the solute and the total mass of the solution. Therefore, we can calculate the mass of the solute using the following formula:
Mass of solute = Mass of solution x Mass percent of solute
Mass of solute = [tex]327.0 g * 0.65 = 212.55 g[/tex]
Therefore, the mass of the solute is 212.55 g.
3. The molarity of 171g of KBr dissolved in 829.0 mL of pure water is 1.74 M.
To calculate the molarity of KBr in the solution, we need to first calculate the number of moles of KBr present in the solution using the following formula:
Number of moles = Mass of solute / Molar mass of KBr
The molar mass of KBr is 119 g/mol (39 g/mol for K and 80 g/mol for Br).
Number of moles = 171 g / 119 g/mol = 1.44 mol
The volume of the solution is given in mL, so we need to convert it to liters:
Volume of solution = 829.0 mL = 0.8290 L
Now, we can calculate the molarity using the following formula:
Molarity = Number of moles / Volume of solution
Molarity = 1.44 mol / 0.8290 L = 1.74 M
Therefore, the molarity of the KBr solution is 1.74 M.
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Deducing a rate law from the change in concentration over time A chemistry graduate student is studying the rate of this reaction: 2Cl2O5 (g) → 2CL2 (g) + 5O2 (g) He fills a reaction vessel with Cl20, and measures its concentration as the reaction proceeds time [Cl2O5] (milliseconds)
0 0.900 M 10 0.506 M 20 0.352 M 30 0.270 M 40 0.219 M
Use this data to answer the following questions.
Write the rate law for this reaction. rate = k ___
Calculate the value of the rate constant k.
Round your answer to 2 significant digits. Alse be sure your answer has the correct unit symbol. k = ___
a. The rate law for the reaction [tex]2Cl_{2}O_{5}[/tex](g) → [tex]2Cl_{2}[/tex](g) + [tex]5O_{2}[/tex](g) is rate = k[[tex]Cl_{2}O_{5}[/tex]]2
b. The rate constant is k = 0.0489 [tex]M^{-2}/ms^{-1}[/tex].
To write the rаte lаw for this reаction, we need to check how the rаte of the reаction chаnges for the chаnge in the concentrаtion of the reаctаnts or products. To get the rаte of the reаction, we need to find out the chаnge in concentrаtion per unit of time. So, the initiаl rаte of reаction (r) will be given by:
r = {Δ[[tex]Cl_{2}O_{5}[/tex]]/Δt}
where Δ[[tex]Cl_{2}O_{5}[/tex]] is the chаnge in concentrаtion аnd Δt is the chаnge in time.
Аs per the аbove formulа, the initiаl rаte of the reаction is:
r = {(0.900 - 0.506)/(10 - 0)} M/ms
= 0.0397 M/ms
Аs per the stoichiometry of the reаction, 2 moles of [tex]Cl_{2}O_{5}[/tex] produces 2 moles of [tex]Cl_{2}[/tex] аnd 5 moles of [tex]O_{2}[/tex]. Thus, the rаte lаw for the given reаction is:
rаte = k[Cl2O5]2
Here, the rаte constаnt is k.
Now, putting the given vаlues in the rаte lаw аnd solving for k:
k = rаte/[[tex]Cl_{2}O_{5}[/tex]]2
Now, the initiаl rаte of the reаction, rаte = 0.0397 M/ms
Аnd the concentrаtion of [tex]Cl_{2}O_{5}[/tex] аt the beginning of the reаction, [[tex]Cl_{2}O_{5}[/tex]] = 0.900 M
So,
k = 0.0397/(0.900)2
= 0.0489 [tex]M^{-2}/ms^{-1}[/tex]
Thus, the rаte lаw for the given reаction is rаte = k[[tex]Cl_{2}O_{5}[/tex]]2 аnd the rаte constаnt is k = 0.0489 [tex]M^{-2}/ms^{-1}[/tex].
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What do these two changes have in common? a piece of pear turning brown and bleaching clothes
Both are caused by cooling.
Both are changes of state.
Both are chemical changes.
Both are caused by heating.
Answer:
Neither of these changes are caused by cooling, but both are chemical changes.
Which of the following sets of words are not related? frequency, energy blackbody curve, intensity temperature, peak wavelength Doppler effect, transverse motion
Answer:
Temperature and transverse motion are not related.
Explanation:
8.45 x 10^23 molecules ch4
The number of mole of the sample containing 8.45×10²³ molecules CH₄ is 1.4 mole
How do I determine the number of mole?Avogadro's hypothesis gives a well defined relationship between number of mole and number of molecules. This is given below:
6.022×10²³ molecules = 1 mole of substance
Thus, we can say that 1 mole of methane, CH₄ will be equivalent to 6.022×10²³ molecules as shown below:
6.022×10²³ molecules = 1 mole of CH₄
With the above information, we can determine the number of mole containing 8.45×10²³ molecules. Details below:
6.022×10²³ molecules = 1 mole of CH₄
8.45×10²³ molecules = 8.45×10²³ / 6.022×10²³
8.45×10²³ molecules = 1.4 mole of CH₄
Thus, the number of mole is 1.4 mole
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Complete question:
What is the number of mole of a sample containing 8.45×10²³ molecules CH₄
if the reaction is 39% complete at the end of 23 s, what is the length of the half-life of this reaction in seconds? use 2 significant figures in your answer. do not include the unit
The length of the half-life is 1.8 seconds (rounded to two significant figures).
The half-life of a reaction is the amount of time it takes for half of the reactants to be consumed. The following is a solution to the problem:
If the reaction is 39% complete at the end of 23 seconds, we can assume that the remaining 61% of reactants will require another half-life to be consumed, which means that half of 61% (or 30.5%) will be consumed in the second half-life.
The percentage remaining after one half-life is 50%, and the percentage remaining after two half-lives is 50% of 50%, or 25%. Therefore, the reaction will be 61% complete after the first half-life, 30.5% complete after the second half-life, and 15.25% complete after the third half-life.
Since the reaction is 39% complete after the first half-life, we can use the following equation to find the length of the half-life: 39% = 100% × (1/2)^(t/h)where t/h represents the length of the half-life. In order to solve for t/h, we can divide both sides by 100% and take the logarithm of both sides:
ln(0.39) = ln(0.5) × (t/h). We can now solve for t/h by dividing both sides by ln(0.5):t/h = ln(0.39) / ln(0.5) = 1.79.
Therefore, the length of the half-life is 1.8 seconds (rounded to two significant figures).
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M bromoaniline dayazonium to m bromoaniline ,which reagent is preferred
Stannous chloride (SnCl2) in a solution of hydrochloric acid (HCl) is the preferred reagent, also known as the HCl-SnCl2 reduction process, to convert m-bromoaniline diazonium to m-bromoaniline.
Reagents are substances that help a chemical process identify, measure, or make other chemicals. It can be applied to check for the presence or absence of certain compounds, analyse the chemical composition of a substance, or generate the desired outcome. Reagents can be organic or inorganic and can be solid, liquid, or gaseous. They can be either relatively inert or extremely reactive, depending on the intended function. Examples of common reagents include acids, bases, oxidising, reducing, catalytic, and indicator reagents. The specific reaction and the desired outcome, as well as factors like accessibility, cost, and safety, all have an impact on the reagent selection.
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a chemist carefully measures the amount of heat needed to raise the temperature of a 809.0 mg sample of from to c3h9n. the experiment shows that of heat are needed. what can the chemist report for the molar heat capacity of ? round your answer to significant digits.
the chemist can report that the molar heat capacity of [tex]C_{3} H_{9}N[/tex] is 134.0 J/mol·K (rounded to three significant digits).
To calculate the molar heat capacity of [tex]C_{3} H_{9}N[/tex] , we need to know the number of moles of [tex]C_{3} H_{9}N[/tex] in the sample and the amount of heat absorbed by the sample. We can use the following formula to calculate the number of moles of [tex]C_{3} H_{9}N[/tex]
n = m/M
where:
n = number of moles
m = mass of [tex]C_{3} H_{9}N[/tex] (809.0 mg)
M = molar mass of [tex]C_{3} H_{9}N[/tex]
The molar mass of [tex]C_{3} H_{9}N[/tex] can be calculated as follows:
M = (3 x M(C)) + (9 x M(H)) + M(N)
Using the atomic masses of the elements from the periodic table, we can calculate the molar mass of [tex]C_{3} H_{9}N[/tex] as follows:
M(C) = 12.01 g/mol
M(H) = 1.008 g/mol
M(N) = 14.01 g/mol
M = (3 x 12.01) + (9 x 1.008) + 14.01 = 59.11 g/mol
Now we can calculate the number of moles of [tex]C_{3} H_{9}N[/tex]
n = 809.0 mg / 59.11 g/mol = 0.01368 mol
Next, we can use the following formula to calculate the molar heat capacity of [tex]C_{3} H_{9}N[/tex]
Cp = q/nΔT
We are given that q = 1834 J and we need to assume a value for ΔT. Let's assume that the temperature of the sample increased by 10.0°C (which is equivalent to 10.0 K). Then we can calculate the molar heat capacity of [tex]C_{3} H_{9}N[/tex] as follows:
Cp = 1834 J / (0.01368 mol x 10.0 K) = 134.0 J/mol·K
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Heyy can someone plsss help me with this question!!!
From your reading of these poems, what was the impact of the Tang wars on the poet Du Fu personally, and on Chinese society in general?
The Quantashia, the largest collection of Tang poetry, has over 48,900 lyrics by more than 2,200 poets. Because poetry was such a huge part of the Tang Dynasty's culture at the time, a significant amount of it has remained. It had great impact on Chianese society.
Poetry remained a significant component of social life at all societal levels during the Tang period. For the civil service tests, scholars had to be proficient in poetry, but everyone had access to it in theory. This resulted to a significant record of poetry and poets, a fragmentary record of which persists today. Li Bai and Du Fu were two of the most well-known poets of the day. Chinese educated people today are familiar with Tang poetry because to the Three Hundred Tang Poems.
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Can someone please help with this chemistry question
According to the question the mass of 12 needed to react exactly with 35 g Al is 420 g.
What is react?React is an open-source JavaScript library created by Face book for building user interfaces. It is a declarative, efficient, and flexible JavaScript library for building user interfaces. React allows developers to create large web applications that use data and can change over time without reloading the page. It is easy to use and requires minimal coding. React is used for developing complex and interactive UIs for web and mobile applications, as well as for creating single-page applications.
The balanced equation for the reaction is:
12 mol A l + 12 mol O2 -> 13 mol Al2O3
We can calculate the mass of 12 needed to react with 35 g A l using the following equation:
Mass (12) = (35 g Al / (12 mol A l/mol 12)) x (12 mol 12/1 mol Al)
= 420 g 12
Therefore, the mass of 12 needed to react exactly with 35 g A l is 420 g.
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Balance the following equations and state what reaction type is taking place
2Al + 6HCl → 3H2 + 2AlCl3, It is a redox reaction ; Cu(OH)2 → H2O + CuO and this is a decomposition reaction.
What is balancing a chemical equation?Balanced chemical equation is that equation where number of atoms of each type in the reaction is same on both the reactants and product sides.
Balanced chemical equation for the reaction between aluminum (Al) and hydrochloric acid (HCl) is: 2Al + 6HCl → 3H2 + 2AlCl3
This is a redox reaction, where aluminum is oxidized to Al3+ and hydrogen ions (H+) are reduced to hydrogen gas (H2).
Balanced chemical equation for the given reaction is: Cu(OH)2 → H2O + CuO
To balance this equation, we need to put a coefficient of 1 in front of Cu(OH)2, 1 in front of H2O, and 1 in front of CuO.
This is a decomposition reaction where Copper (II) hydroxide (Cu(OH)2) breaks down into water (H2O) and Copper (II) oxide (CuO).
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Name the planet: This greenish-blue planet's axis of rotation is sideways and takes 84 years to revolve around the sun
The planet being described is Uranus.
Uranus is the seventh planet from the sun in our solar system, and it is known for its distinctive greenish-blue color. It is a gas giant planet, similar in composition to Jupiter and Saturn, and it is much larger than Earth, with a diameter of about 51,118 km.
One of the most unique features of Uranus is its axis of rotation, which is tilted at an angle of about 98 degrees relative to its orbit around the sun. This means that instead of spinning upright like most other planets, Uranus appears to be rolling on its side. As a result, its seasons are much more extreme than those of other planets, with each pole experiencing 42 years of continuous daylight followed by 42 years of continuous darkness.
Uranus takes about 84 years to complete one orbit around the sun, which means that it spends roughly 7 years in each zodiac sign. This long orbital period, combined with its distance from Earth, means that it was not discovered until relatively recently in human history. It was first observed by the astronomer William Herschel in 1781, and it was named after the ancient Greek deity of the sky.
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would you rather live in an Aerobic environment or an anaerobic one? explain your answer
Yes I would live in Aerobics environment because I need oxygen to thrive, and survive.
What is the important of aerobic environment to humans?
Humans require an aerobic environment to live. Aerobic means "with oxygen," and the human body needs oxygen to produce energy through a process called cellular respiration. Without oxygen, cells cannot produce enough energy to sustain life. In contrast, anaerobic environments lack oxygen and can be toxic to humans.
In general, humans have evolved to live in aerobic environments, and our bodies are well-equipped to handle normal levels of oxygen in the air. However, exposure to high levels of oxygen can also be harmful, as it can lead to oxidative stress and damage to cells. Similarly, exposure to low levels of oxygen, such as in high-altitude environments, can also be challenging for humans.
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To earn full credit for your answers, you must show the appropriate formula, the correct substitutions , and your answer including the correct units
A pod of 51 orcas has 15 births and 8 deaths.
How many years will it take for the population of orca to double?
The number of years it will take for the population of orcas to double, given the births and deaths is 5. 10 years .
How to find the population doubling time ?To find the population doubling time, we first need to find the rate at which the population of orcas grew in the current year:
= ( 15 births - 8 deaths ) / 51 orcas
= 7 / 51 x 100 %
= 13. 7 %
Then, we can use the Rule of 70 to find the doubling time. The Rule of 70 shows the periods till doubling as :
= 70 / growth rate
= 70 / 13.7
= 5. 10 years
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How much of a 10 M solution is needed to make 1 liter of a 1 M solution?
1 mL
10 mL
100 mL
1000 mL
We need to add 100 mL (0.1 liter) of the 10 M solution to 900 mL (0.9 liter) of solvent to make 1 liter of a 1 M solution. Option C is correct.
To make a 1 liter solution of 1 M concentration, we need to dilute the 10 M solution by a factor of 10.
The dilution factor is the ratio of the final volume to the initial volume, which is 1 liter / 0.1 liter = 10.
So, we need to add 1 part of the 10 M solution to 9 parts of solvent (usually water) to make a total of 10 parts, which will result in a 1 M solution.
Therefore, we need to add 100 mL (0.1 liter) of the 10 M solution to 900 mL (0.9 liter) of solvent to make 1 liter of a 1 M solution.
Hence, C. 100 mL is the correct option.
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--The given question is incomplete, the complete question is
"How much of a 10 M solution is needed to make 1 liter of a 1 M solution? A) 1 mL B) 10 mL C) 100 mL D) 1000 mL."--
Step 2: Show the conversions required to solve this problem and calculate the grams of KCIO3.
20.8 g 0₂ ×
122.55 g KCIO,
32.00 g 0₂
74.55 g KCI
X
Answer Bank
1 mole KCIO3
1 mole 0₂
1 mole KCI
X
2 moles KCIO,
3 moles 0₂
2 moles KCI
= g KC103
The grams of KCIO3 are 4.05 g.
What is the purpose of using dimensional analysis in this problem?Dimensional analysis is used to cancel units and convert between different quantities (moles, grams, etc.) in a systematic and logical way. By using conversion factors, we can ensure that our calculations are accurate and that we arrive at the correct units for the final answer.
Why do we need to convert the moles of O2 to moles of KCIO3 before finding the grams of KCIO3?We need to convert the moles of O2 to moles of KCIO3 because we are ultimately interested in finding the mass of KCIO3. By using the conversion factor of 2 moles KCIO3/3 moles O2, we can relate the two quantities and determine the number of moles of KCIO3 required to react with the given mass of O2.
To solve the problem, we need to use the given conversion factors and dimensional analysis to cancel units and find the grams of KCIO3.
Step 1: Write down the given conversion factors:
1 mole KCIO3 = 122.55 g KCIO3
1 mole O2 = 32.00 g O2
2 moles KCIO3 = 3 moles O2
2 moles KCIO3 = 2 moles KCI
Step 2: Write down the given mass of O2 and use it to find the moles of KCIO3:
0.8 g O2 × (1 mole O2/32.00 g O2) × (2 moles KCIO3/3 moles O2) = 0.0333 moles KCIO3
Step 3: Convert the moles of KCIO3 to grams:
0.0333 moles KCIO3 × (122.55 g KCIO3/1 mole KCIO3) = 4.05 g KCIO3
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Consider a buffer solution that is 0. 50 M in NH3 and 0. 20 M in NH4Cl. For ammonia, pKb=4. 75. Calculate the pH of 1. 0 L of the solution upon addition of 30. 0 mL of 1. 0 M HCl to the original buffer solution.
Express your answer to two decimal places
The pH of 1. 0 L of the solution on addition of 30. 0 mL of 1. 0 M HCl to the original buffer solution will be 12.50.
The reaction that occurs when HCl is added to the buffer solution is:
HCl + NH₃ → NH₄⁺ + Cl⁻
The HCl reacts with NH₃ to form NH₄⁺ and Cl⁻. This will cause the concentration of NH₄⁺ in the buffer to increase and the concentration of NH₃ to decrease. However, since we started with a buffer solution, it will still be able to resist changes in pH.
To solve this problem, we will use the Henderson-Hasselbalch equation:
pH = pKb + log([NH₄⁺]/[NH₃])
where [NH₄⁺] is the concentration of the ammonium ion and [NH3] is the concentration of ammonia.
Calculate the moles of HCl added
The volume of HCl added is 30.0 mL = 0.0300 L. The concentration of HCl is 1.0 M, so the moles of HCl added are:
moles of HCl = concentration x volume = 1.0 M x 0.0300 L = 0.0300 moles
Calculate the new concentrations of NH₄⁺ and NH₃
The moles of NH₄⁺ and NH₃ in the original buffer solution can be calculated as:
moles of NH₄⁺ = 0.20 M x 1.0 L = 0.20 moles
moles of NH₃ = 0.50 M x 1.0 L = 0.50 moles
When HCl is added, it reacts with NH₃ to form NH₄⁺ and Cl⁻. The amount of NH₄⁺ produced is equal to the amount of HCl added, since the reaction is 1:1. Therefore, the new concentration of NH₄⁺ is:
[NH₄⁺] = moles of NH₄⁺ / (volume of buffer + volume of HCl added)
[NH₄⁺] = 0.20 moles / (1.0 L + 0.0300 L)
[NH₄⁺] = 0.196 M
The new concentration of NH₃ can be calculated using the buffer equation:
[NH₃] = Ka x [NH₄⁺] / [H⁺]
where Ka is the equilibrium constant for the reaction NH₄⁺ + H₂O → NH₃ + H₃O⁺, which is equal to the acid dissociation constant of NH₃, Kb. Since pKb is given as 4.75, we can calculate Kb:
Kb = 10^(-pKb) = [tex]10^{-4.75}[/tex] = 1.78 x 10⁻⁵
Substituting the values we have:
[NH3] = Kb x [NH₄⁺] / [H⁺]
[NH3] = 1.78 x 10⁻⁵ x 0.196 M / [tex]10^{-pH}[/tex]
[NH3] = 3.49 x 10⁻⁶ / [tex]10^{-pH}[/tex]
Calculate the new pH of the buffer
Substituting the values we have into the Henderson-Hasselbalch equation:
pH = pKb + log([NH₄⁺]/[NH₃])
pH = 4.75 + log(0.196 M / (3.49 x 10⁻⁶ / [tex]10^{-pH}[/tex])))
Simplifying and solving for pH:
pH = 4.75 + log(5.61 x 10⁷) + log([tex]10^{pH}[/tex])
pH = 4.75 + 7.75 + pH
pH = 12.50
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If 78. 2 grams of oxygen (O2) react with plenty of copper Cu, how many moles of
copper (II) oxide (CuO) will be produced?
Answer:
The molar mass of oxygen is 32 g. Hence the number of moles of oxygen are: 78.2 g / (32 g/mole) = 78.2/32 moles Since 1 mole of oxygen produces 2 moles of copper oxide, the number of moles of copper oxide generated are: (78.2/32) x 2 moles = 4.89 moles of copper oxide.
Explanation:
Model It! Dry Ice Figure 8 Dry ice sublimes, changing directly from a solid to a gas. SEP Develop Models Think about what is happening to the particles of carbon dioxide as the dry ice changes from solid to gas. Draw models of the particles in the two phases of matter. Use an arrow to show the flow of thermal energy into the solid carbon dioxide.
model of the particles in solid carbon dioxide (dry ice):
__ __
/ \ / \
| o | | o |
\____/ \____/
model of the particles in gaseous carbon dioxide:
o o
o
o o
The arrows showing the flow of thermal energy into the solid carbon dioxide could be represented as:
__ __
/ \ / \
| → | | o |
\____/ \____/
The arrow depicts how heat energy is transferred into the solid carbon dioxide, causing it to sublime and become gaseous carbon dioxide.
Carbon dioxide exists in a solid form as dry ice. It directly transforms into a gas when brought to room temperature, a process known as sublimation.
Thermal energy is introduced into the solid carbon dioxide during this process, causing its particles to separate and turn into a gas.
The discharge of the gas is caused by the gaseous carbon dioxide particles' increased freedom of movement and spreading out.
In conclusion, dry ice is an intriguing substance that transforms through a special process known as sublimation from a solid to a gas. This process happens as a result of thermal energy entering the solid and forcing its particles to disperse and turn into a gas.
Science-related fields like cryogenics, food preservation, and even special effects can benefit from understanding the behavior of dry ice and the underlying concepts of sublimation.
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Please help me on this. I have no idea how to figure this out.
The season the northern hemisphere is experiencing is A, summer.
When do these seasons occur?Summer: June solstice to September equinox. Summer is the season that follows spring and precedes fall. It typically begins around June 20th or 21st and lasts until around September 22nd or 23rd.
Fall (Autumn): September equinox to December solstice. Fall is the season that follows summer and precedes winter. It typically begins around September 22nd or 23rd and lasts until around December 20th or 21st.
Winter: December solstice to March equinox. Winter is the season that follows fall and precedes spring. It typically begins around December 20th or 21st and lasts until around March 20th or 21st.
Spring: March equinox to June solstice. Spring is the season that follows winter and precedes summer. It typically begins around March 20th or 21st and lasts until around June 20th or 21st.
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Image transcribed:
BAND HALL
Earth and Space
What season is the northern hemisphere experiencing?
A Summer
B. Spring
C. Winter
D. Fall
You are given 100 ml of a solution of potassium hydroxide with a ph of 12. 0. You are required to change the pH to 11. 0 by adding water. How much water do you add
Explanation:
To calculate the amount of water needed to dilute the solution of potassium hydroxide and change its pH from 12.0 to 11.0, we need to use the formula for calculating the pH of a diluted solution.
The formula is:
pH = -log[H+]
where [H+] is the concentration of hydrogen ions in moles per liter.
Since we are diluting the solution by adding water, the concentration of [OH-] (hydroxide ions) will decrease proportionally to the volume of water added. This means that we can use the following equation to calculate the new concentration of [OH-]:
[OH-]1V1 = [OH-]2V2
where V1 is the initial volume of the solution, [OH-]1 is the initial concentration of hydroxide ions, V2 is the final volume of the solution after dilution, and [OH-]2 is the final concentration of hydroxide ions.
We know that the initial pH is 12.0, which means that [OH-]1 = 10^-2.0 M = 0.01 M.
We want to change the pH to 11.0, which means that [OH-]2 = 10^-11.0 M = 1 x 10^-11 M.
We also know that we are adding water to dilute the solution, but we don't know how much water we need to add yet. Let's call this volume of water "Vw".
Using the equation above, we can solve for V2:
[OH-]1V1 = [OH-]2V2
(0.01 M)(100 ml) = (1 x 10^-11 M)(100 ml + Vw)
V2 = (0.01 M)(100 ml)/(1 x 10^-11 M) - Vw
V2 = 10^12 ml - Vw
Now we can use this value for V2 in the pH formula to calculate the new pH:
pH = -log([H+])
[H+] = Kw/[OH-]
Kw is the ion product constant for water, which is equal to 1 x 10^-14 at room temperature.
[H+] = (1 x 10^-14)/(1 x 10^-11)
[H+] = 1 x 10^-3 M
pH = -log(1 x 10^-3)
pH = 3
We want to achieve a pH of 11.0, so we need to add enough water to bring down the pH from 12.0 to 11.0. This means that we need to add enough water so that V2 becomes:
V2 = (0.01 M)(100 ml)/(1 x 10^-11 M) - Vw = 10^11 ml
Therefore, we need to add:
Vw = V2 - initial volume of solution
Vw = (10^11 ml) - (100 ml)
Vw = 99999900 ml or approximately 100 million ml or 100 cubic meters of water.
So, in order to change the pH of a solution of potassium hydroxide with a pH of 12.0 to a pH of 11.0 by adding water only, you would need to add approximately 100 million milliliters or about 100 cubic meters of water.
who has the low density.... lithium or lead and why??
Answer:
Lithium has a lower density than lead.
The density of an element is determined by its atomic mass and the packing arrangement of its atoms. Lithium has an atomic mass of 6.94 atomic mass units (amu), while lead has an atomic mass of 207.2 amu, which is significantly higher.
In addition to atomic mass, the density of an element is also affected by the arrangement of its atoms. Lithium has a much larger atomic radius than lead, meaning that its atoms are less tightly packed together. This results in a lower overall density for lithium compared to lead.
To provide some context, the density of lithium is approximately 0.53 grams per cubic centimeter (g/cm3), while the density of lead is approximately 11.34 g/cm3. This means that lead is about 21 times denser than lithium.
A 500. 0-mL buffer solution is 0. 100 M in HNO2 and 0. 150 M in KNO2. Part A Determine whether or not 250 mgNaOH would exceed the capacity of the buffer to neutralize it. Determine whether or not 250 would exceed the capacity of the buffer to neutralize it. Yes no Request Answer Part B Determine whether or not 350 mgKOH would exceed the capacity of the buffer to neutralize it. Determine whether or not 350 would exceed the capacity of the buffer to neutralize it. Yes no Request Answer Part C Determine whether or not 1. 25 gHBr would exceed the capacity of the buffer to neutralize it. Determine whether or not 1. 25 would exceed the capacity of the buffer to neutralize it. Yes no Request Answer Part D Determine whether or not 1. 35 gHI would exceed the capacity of the buffer to neutralize it. Determine whether or not 1. 35 would exceed the capacity of the buffer to neutralize it. Yes no
Part A: No, 250 mg NaOH would not exceed the capacity of the buffer to neutralize it.
Part B: No, 350 mg KOH would not exceed the capacity of the buffer to neutralize it.
Part C: Yes, 1. 25 g HBr would exceed the capacity of the buffer to neutralize it.
Part D: Yes, 1. 35 g HI would exceed the capacity of the buffer to neutralize it.
Part A:
We first need to calculate the pH of the buffer solution using the Henderson-Hasselbalch equation to see if 250 mg NaOH would surpass the buffer's ability to neutralise it:
pH = pKa + log([[tex]A^-[/tex]]/[HA])
where
pKa is the acid dissociation constant of [tex]HNO_2[/tex],
[[tex]A^-[/tex]] is the conjugate base concentration ([tex]NO_2^-[/tex]),
[HA] is the acid concentratio ([tex]HNO_2[/tex]).
The pKa of [tex]HNO_2[/tex] is 3.15, so:
pH = 3.15 + log([[tex]NO_2^-[/tex]]/[[tex]HNO_2[/tex]])
pH = 3.15 + log(0.150/0.100)
pH = 3.40
The buffer is a basic buffer since its pH is higher than 7.
As a result, we must determine how many moles of [tex]NO_2^-[/tex] there are in 500.0 mL of the buffer solution:
moles of [tex]NO_2^-[/tex] = concentration x volume
moles of [tex]NO_2^-[/tex] = 0.150 mol/L x 0.500 L
moles of [tex]NO_2^-[/tex] = 0.075 mol
It is necessary to convert 250 mg of NaOH into moles in order to assess whether the buffer can neutralise it:
moles of NaOH = mass / molar mass
moles of NaOH = 0.250 g / 40.00 g/mol
moles of NaOH = 0.00625 mol
Since
[tex]NaOH + HNO_2[/tex] → [tex]NaNO_2 + H_2O[/tex]
The amount of [tex]HNO_2[/tex] consumed by 0.00625 mol of NaOH is:
moles of [tex]HNO_2[/tex] consumed = 0.00625 mol
Since
the buffer initially contained 0.100 mol/L of [tex]HNO_2[/tex], the number of moles of [tex]HNO_2[/tex] in 500.0 mL of the buffer solution is:
moles of [tex]HNO_2[/tex] = concentration x volume
moles of [tex]HNO_2[/tex] = 0.100 mol/L x 0.500 L
moles of [tex]HNO_2[/tex] = 0.050 mol
Consequently, 0.050 mol of [tex]HNO_2[/tex] can be neutralised by the buffer, while 0.00625 mol of [tex]HNO_2[/tex] is actually consumed by 0.00625 mol of NaOH. The buffer can neutralise 250 mg of NaOH because the amount of [tex]HNO_2[/tex] used by the NaOH is less than the amount of [tex]HNO_2[/tex] present initially.
Part B:
Evaluate if 350 mg KOH would be too much for the buffer to neutralise.
We must first determine the buffer solution's pH:
pH = pKa + log([[tex]A^-[/tex]]/[HA])
pH = 3.15 + log([tex][NO_2^-]/[HNO_2][/tex])
pH = 3.15 + log(0.150/0.100)
pH = 3.40
Since
The buffer is a basic buffer since its pH is higher than 7.
The concentration of the conjugate base in the buffer solution determines a basic buffer's ability to neutralize a base (like KOH). As a result, we must determine how many moles of [tex]NO_2^-[/tex] there are in 500.0 mL of the buffer solution:
moles of [tex]NO_2^-[/tex] = concentration x volume
moles of [tex]NO_2^-[/tex] = 0.150 mol/L x 0.500 L
moles of [tex]NO_2^-[/tex] = 0.075 mol
To find whether the buffer can neutralize 350 mg KOH, we need to convert 350 mg to moles:
moles of KOH = mass / molar mass
moles of KOH = 0.350 g / 56.11 g/mol
moles of KOH = 0.00624 mol
Since
KOH is a strong base, it will react completely with the [tex]HNO_2[/tex] in the buffer to form [tex]KNO_2[/tex] and water:
[tex]KOH + HNO_2[/tex] → [tex]KNO_2 + H_2O[/tex]
The amount of [tex]HNO_2[/tex] consumed by 0.00624 mol of KOH is:
moles of [tex]HNO_2[/tex] consumed = 0.00624 mol
Since
[tex]HNO_2[/tex] was initially present in the buffer at a concentration of 0.100 mol/L; hence, there are 500.0 mmol of [tex]HNO_2[/tex] in the buffer solution.
moles of [tex]HNO_2[/tex] = concentration x volume
moles of [tex]HNO_2[/tex] = 0.100 mol/L x 0.500 L
moles of [tex]HNO_2[/tex] = 0.050 mol
As a result, 0.050 mol of [tex]HNO_2[/tex] can be neutralised by the buffer, while 0.00624 mol of [tex]HNO_2[/tex] is actually consumed by 0.00624 mol of KOH. The buffer can neutralise 350 mg of KOH because the amount of [tex]HNO_2[/tex]used by the KOH is smaller than the amount of [tex]HNO_2[/tex] present at first in the buffer.
Part C:
We must first decide if 1.25 g of HBr is an acid or a basic in order to assess whether it would be too much for the buffer to neutralise.
As HBr is an acid and the problem's buffer is a basic buffer, an acid cannot be neutralised.
Consequently, we may deduce that the buffer is unable to neutralise 1.25 g HBr without having to conduct any computations.
Part D:
We must first decide if 1.35 g of HI is an acid or a basic in order to assess whether it would be too much for the buffer to neutralise.
As HI is an acid and the problem's buffer is a basic buffer, an acid cannot be neutralised by it.
Consequently, we may deduce that the buffer is unable to neutralise 1.35 g of HI without having to conduct any computations.
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decomposition of ozone to oxygen occurs as a series of radical reactions. the individual reactions in this series are listed below but they are not in the correct order. use the labels on the right to correct the order of the reactions.
The correct order of the reactions for the decomposition reaction of ozone to oxygen is as follows:
O3 + O → 2 O2O3 + O → 2 O2O3 + O → 2 O2This series of radical reactions occurs in the stratosphere, where ozone O3 and an oxygen atom (O). The oxygen atom then reacts with another ozone molecule in the second reaction, forming two oxygen molecules. The third reaction is similar to the first, with an ozone molecule reacting with an oxygen atom to form two oxygen molecules. These reactions continue until all of the ozone has been converted to oxygen.
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Explain how sunlight can cause a crack in the street.
The equilibrium constant, Kc, for the following reaction is 9.52×10-2 at 350 K:CH4(g) + CCl4(g) 2CH2Cl2(g)Calculate the equilibrium concentrations of reactants and product when 0.374 moles of CH4 and 0.374 moles of CCl4 are introduced into a 1.00 L vessel at 350 K.[CH4] = M[CCl4] = M[CH2Cl2] = M
The equilibrium concentrations are 0.247 M for CH4 and CCl4, and 0.254 M for CH2Cl2.
The equilibrium constant, Kc, is given by the expression:
Kc = [CH2Cl2]² / ([CH4] [CCl4])
We are given the initial concentrations of CH4 and CCl4:
[CH4] = 0.374 M
[CCl4] = 0.374 M
Let x be the change in concentration at equilibrium. The equilibrium concentrations can be expressed as:
[CH4] = 0.374 - x
[CCl4] = 0.374 - x
[CH2Cl2] = 2x
Substituting these values into the expression for Kc, we get:
9.52×10-2 = (2x)² / ((0.374 - x) (0.374 - x))
Solving for x, we get:
x = 0.127 M
Therefore, the equilibrium concentrations are:
[CH4] = 0.374 - 0.127 = 0.247 M
[CCl4] = 0.374 - 0.127 = 0.247 M
[CH2Cl2] = 2(0.127) = 0.254 M
Answer: The equilibrium concentrations are 0.247 M for CH4 and CCl4, and 0.254 M for CH2Cl2.
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explain why the procedure for the amino acid chromatography states that you are to be careful not to touch the paper with your fingers, except along the edges.
The procedure for the amino acid chromatography states that you are to be careful not to touch the paper with your fingers, except along the edges, to prevent contamination of the paper or the sample. Chromatography is a technique used in the separation of different molecules or components of a mixture. It involves the movement of the components of a mixture through a stationary phase, which is usually a solid or liquid, in a mobile phase or a gas or liquid.
Chromatography is used in the separation and identification of amino acids, which are the building blocks of proteins. In amino acid chromatography, the stationary phase is a special paper or a silica gel-coated plate, and the mobile phase is a solvent, usually a mixture of water and an organic solvent.
When performing amino acid chromatography, it is crucial to avoid contamination of the paper or the sample with any foreign substances, such as dust, oil, or bacteria, which can interfere with the separation and identification of the amino acids. Therefore, it is essential to handle the paper with care and avoid touching it with bare hands.
The oils and sweat present on the hands can leave behind residues on the paper that can interfere with the separation process. Therefore, one should avoid touching the paper except along the edges, where there is less chance of contaminating the sample. To handle the paper, it is best to use forceps or gloves that do not leave behind any residues.
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PLEASE ANSWER!!!
Using Graham's Law of Effusion, calculate
the approximate time it would take for
1. 0 L of argon gas to effuse, if 1. 0 L of
oxygen gas took 12. 7 minutes to effuse
through the same opening.
0. 070 minutes
0. 89 minutes
None of the other answers
14 minutes
12 minutes
The correct answer is None of the other answers. According to Graham's Law of Effusion, the rate of effusion of a gas is inversely proportional to the square root of its molar mass. This means that a gas with a lower molar mass will effuse faster than a gas with a higher molar mass.
The equation for Graham's Law of Effusion is:
Rate of effusion of gas 1/Rate of effusion of gas 2 = √(Molar mass of gas 2/Molar mass of gas 1).
In this case, we are given the rate of effusion of oxygen gas (12.7 minutes) and asked to find the rate of effusion of argon gas.
The molar mass of oxygen gas is 32 g/mol and the molar mass of argon gas is 40 g/mol.
Plugging in the given values into the equation, we get:
Rate of effusion of argon/12.7 minutes = √(32 g/mol/40 g/mol)
Cross-multiplying and solving for the rate of effusion of argon, we get:
Rate of effusion of argon = 12.7 minutes × √(32 g/mol/40 g/mol) = 11.3 minutes.
Therefore, the approximate time it would take for 1.0 L of argon gas to effuse is 11.3 minutes. This is not one of the answer choices, so the correct answer is None of the other answers.
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1. 2 NH3 + 3 CuO g 3 Cu + N2 + 3 H2O In the above equation how many moles of water can be made when 36 moles of NH3 are consumed?
2. 3 Cu + 8HNO3 g 3 Cu(NO3)2 + 2 NO + 4 H2O
In the above equation how many moles of NO can be made when 86 moles of HNO3 are consumed?
3. 3 Cu + 8HNO3 --> 3 Cu(NO3)2 + 2 NO + 4 H2O
In the above equation how many moles of water can be made when 82 moles of HNO3 are consumed?
Sodium chlorate decomposes into sodium chloride and oxygen gas as seen in the equation below.
4. 2NaClO3 --> 2NaCl +3O2
How many moles of NaClO3 were needed to produce 56 moles of O2? Round your answer to the nearest whole number.
pls i already asked for help with this but im honestly just so lost and my parents dont understand. i really need this done and ive been trying to understand it and figure it out but i cant
Answer:
3, 2, 1, 6
Explanation:
Let's do some algebra lol
Let's call coefficient for Cu(NO3)2 "a"
Let's call coefficient for K3PO4 "b"
Let's call coefficient for Cu3(PO4)2 "c"
Let's call coefficient for KNO3 "d"
Cu3(PO4)2 has 3x as many moles of Cu compared to Cu(NO3)2, so we know that 3c = a
Cu(NO3)2 has 2x as many moles of NO3 compared to KNO3, so we know that 2a = d
Repeat this process for K and PO4 --> you get equations 3b = d and 2c = b respectively
2a = d = 3b = d so 2a = 3b, let's see if a = 3, b = 2 works
plug a and b into other two equations --> c = 1, d = 6
these are all whole numbers so it works! (if they're not whole numbers than multiply every coefficient by their LCM to make it whole)
so your coefficients for each of them are 3, 2, 1, 6