Pasos a seguir para realizar la nomenclatura común y la nomenclatura IUPAC

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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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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The number of mole of the sample containing 8.45×10²³ molecules CH₄ is 1.4 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

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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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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3.0 grams of NaHCO₃  will receive about 1.76 kJ of heat during the decomposition process.

To calculate the amount of heat absorbed when 3.0 grams of NaHCO₃ decompose, we need to first determine the limiting reactant and then use the balanced chemical equation and the enthalpy change to calculate the amount of heat absorbed.

The balanced chemical equation for the decomposition of NaHCO₃ is:

2 NaHCO₃(s) → Na₂CO₃(s) + CO₂(g) + H₂O(g)

The enthalpy change for this reaction is not given, but assuming it is an endothermic reaction, the heat absorbed can be represented as a positive value.

First, we need to determine the limiting reactant. The molar mass of NaHCO₃ is:

NaHCO₃: 23.0 + 1.0 + 12.0 + 48.0 = 84.0 g/mol

Using the molar mass, we can convert 3.0 g of NaHCO₃ to moles:

3.0 g NaHCO₃ x (1 mol NaHCO₃/84.0 g NaHCO₃) = 0.0357 mol NaHCO₃

From the balanced equation, we know that 2 moles of NaHCO₃ produces 1 mole of CO₂. So, the moles of CO₂ produced from 0.0357 mol of NaHCO₃ is:

0.0357 mol NaHCO₃ x (1 mol CO₂/2 mol NaHCO₃) = 0.0179 mol CO₂

Next, we can use the enthalpy change for the reaction and the moles of CO₂ produced to calculate the heat absorbed:

0.0179 mol CO₂ x (98 kJ/1 mol) = 1.76 kJ

Therefore, the amount of heat absorbed when 3.0 grams of NaHCO₃ decompose is approximately 1.76 kJ.

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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

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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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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The number of years it will take for the population of orcas to double, given the births and deaths is 5. 10 years .

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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Answer:

Temperature and transverse motion are not related.

Explanation:

Explanation:

1 solution

2 liquid dispersed in gas

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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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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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:

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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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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The correct order of the reactions for the decomposition reaction of ozone to oxygen is as follows:

This 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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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​."--

Answer:

Neither of these changes are caused by cooling, but both are chemical changes.

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.

According to the question the mass of 12 needed to react exactly with 35 g Al is 420 g.

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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please make me brainalist and keep smiling dude

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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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.

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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The season the northern hemisphere is experiencing is A, summer.

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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BAND HALL

Earth and Space

What season is the northern hemisphere experiencing?

A Summer

B. Spring

C. Winter

D. Fall