Answer:
+47°C
Explanation:
ΔT means change in temperature. If the change is positive, it means that heat was added and the temperature went up.
ΔT = final temp - initial temp
ΔT = 86°C -39°C = + 47°C
which of these elements is most likely to be magnesium the most metallic of all samples?
Answer:
B
Explanation:
Just did it on usa test prep
The element which is most likely to be magnesium is the element with the electronic configuration same as magnesium.
What is an element?It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.
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Which ecosystem is the least stable?
Answer:
tundra bc it has barley any food source and has vary little inhabitants
Explanation:
Answer:
a patch of lichens on bare rock
Light travels at a speed of 3.00 x 100 ^10 cm/s. What is the speed of light in kilometers/hour?
Answer:
1.1 x [tex]10^{9}[/tex] km/h
Explanation:
Here we need to do two conversions- one from centimetres to kilometres and one from seconds to hours.
To get from cm to km- we divide by 100 000 since there are 100 000 cm in a km.
To get from seconds to hours we divide by 3600 since there are 3600 seconds in an hour
[tex]\frac{3*10^{10}cm/100000 }{1second/3600} =1.1*10^{9} km/h[/tex]
Does changing the number of protons change the identity of the element you have built ?
Answer: Yes.
Explanation:
the number of protons in the nucleus determines an element's identity. Chemical changes do not affect the nucleus, so chemical changes cannot change one type of atom into another. The number of protons in a nucleus does change sometimes, however. The identity of the atom, therefore, changes.
Can you explain what vsepr stand for in your own word?
With some manipulation, the Rydberg equation can be rewritten in the form
E=constant×(1nf2−1ni2)
which allows you to calculate the energy of the emitted light. Express this constant in terms of the constants h, c, and RH using relationships between wavelength and energy as well as the Rydberg equation from the introduction.
Express the constant in terms of h and c, and RH.
Please help me with this question?
Answer:
attached below is the detailed solution
answer : value of constant = 2.18 * 10^-18 J
Explanation:
Express the constant in terms of h and c and RH
attached below is the detailed solution
Constant = [tex]h_{C} R_{H}[/tex]
= ( 6.626 * 10^-34 ) * ( 3 * 10^8 ) * ( 1.097 * 10^7 )
= 2.18 * 10^-18 J
The Planck equation and the light speed allow us to find the results for the transformation of the Rydberg equation are:
[tex]E = A ( \frac{1}{n_1^2}\frac{x}{y} - \frac{1}{n_2^2} )\\A= R_H \ h \ c \\A = 2.18 \ 10^{-18} j[/tex]
The Rydberg equation is an empirical expression that explains the wavelength of the emissions.
[tex]\frac{1}{\lambda } = R_H ( \frac{1}{n_1^2} - \frac{1}{n_2^2} )[/tex]
Where λ is the wavelength of the emitted radiation, is the Rydberg constant, n₁ and n₂ are integers with n₁ <n₂
It is asked to write the Rydberg equation for the energy.
Let's use the Planck relation.
E = h f
The light speed is related to the wavelength and frequency of radiation.
c = λ f
Where E is the energy, h the Planck constant, c the speed of light, λ the wavelength and f the frequency.
Let's substitute.
E = [tex]\frac{hc}{\lambda}[/tex]
[tex]\frac{1}{\lambda} = \frac{E}{hc}[/tex]
Let's substitute in the Rydberg equation.
[tex]\frac{E}{hc} = R_H ( \frac{1}{n_1^2} - \frac{1}{n_2^2}) \\E = R_H \ h \ c \ ( \frac{1}{n_1^2} - \frac{1}{n_2^2} )[/tex]
We can write is an constant of the form.
A = [tex]R_H h c[/tex]
The value of the constant is :
A = 1,097 10⁷ 6,626 10⁻³⁴ 3 10⁸
A = 2.18 10⁻¹⁸ J
In conclusion, using the Planck equation and the light speed we can find the results for the transformation of the Rydberg equation are
[tex]E = A ( \frac{1}{n_1^2} - \frac{1}{n_2^2} )\\ A = R_H h c\\[/tex]
A = 2.18 10⁻¹⁸ J
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1. Compare and contrast the characteristics of metals and nonmetals.
2. Describe the electrochemical series and why it’s important in understanding metals.
3. Describe the theory of ionization in regard to acids and bases.
4. Identify the role of indicators.
Answer:
1. Both metals and nonmetals are types of elements and can be involved in chemical reactions. Some of their differences are highlighted in the chart below.
Metals:
Appearance; Shiny.
Conduct heat or electricity; Yes.
Malleable or ductile; Yes, both and has great mechanical strength.
Form stable compounds; Forms stable compounds with acids; also forms oxides; replaces hydrogen in acids or water; combine with nonmetals; often becomes positive.
Nonmetals :
Appearance; Not shiny .
Conduct heat or electricity; Not well .
Malleable or ductile; Brittle and not easily molded into shapes .
Form stable compounds; Oxides usually give acid reactions in water; often becomes negative
2. The electrochemical series is an arrangement of metals in such order that any metal in the list is displaced from its compounds by any metal above it, but displaces any metal below it. The higher up the list a metal is, the greater its activity. Knowing a metal’s placement on this chart can help you understand the activity of the metal, especially in regard to its ability to displace hydrogen in acids. Any items on the list far above hydrogen will do a good job at displacing it, those near it won’t do such a good job, and those below it won’t displace it from acids at all.
3. When placed in water, acids dissociate and form free hydrogen ions, which determine the properties of acids. The number of hydrogen ions determines the strength of an acid. Strong acids dissociate to a large degree and produce a large number of hydrogen ions. Weak acids dissociate to only a slight degree.
When placed in water, bases dissociate and form free hydroxyl ions, which determine the properties of bases. Strong bases dissociate to a great degree and produce a large number of hydroxyl ions. Weak bases dissociate to only a slight degree.
When free hydrogen ions and free hydroxyl ions are removed from solutions of acids and bases, then the acidic and basic properties disappear. This is what happens when acids and bases are mixed together in proper proportion; the hydroxyl ion will unite with the hydrogen ion to form water. The resulting salt product is neutral.
4. Indicators are used to help determine the pH value of an unknown solution. These are often papers that turn a certain color at certain pH values.
Metals are good conductors of heat and electricity but the non-metals are not.
Compare metals and non-metalsMetals are good conductors of electricity and heat whereas non-metals are poor conductors of heat and electricity. Metals have high density while on the other hand, non-metals have low density. Metals are malleable and ductile whereas non-metals are brittle.
So we can conclude that metals are good conductors of heat and electricity but the non-metals are not.
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Jamal is 8 miles away from his house. He rides his bike home toward home at a speed of 12 mph..
How far away from home is he after a half hour?
Answer: 2miles
Explanation:if he’s going 12 miles in one hour, in half an hour he would’ve made it 6 miles. 8-6=2
Answer: b. 2 miles
Explanation:
You just got a free ticket for a boat ride, and you can bring along
2 friends! Unfortunately, you have 5 friends who want to come along.
Answer:
10
Explanation:
Khan Academy
Write a balanced equation for the complete oxidation reaction that occurs when ethane burns in air
Alkanes are saturated hydrocarbons that have single bonds in chains
General formula for alkanes :
[tex]\tt \large{\bold{C_nH_{2n+2}}[/tex]
Hydrocarbon combustion reactions (specifically alkanes)
[tex]\large {\box {\bold{C_nH _ (_2_n _ + _ 2_) + \dfrac {3n + 1} {2} O_2 \Rightarrow nCO_2 + (n + 1) H_2O}}}[/tex]
So that the burning of ethane with air (oxygen):
[tex]\tt C_2H_6+\dfrac{7}{2}O_2\rightarrow 2CO_2+3H_2O[/tex]
2C₂H₆ (g) + 7O₂ (g) ⟶ 4CO₂ (g) + 6H₂O (ℓ)
or we can use mathematical equations to solve equilibrium chemical equations by giving the coefficients for each compound involved in the reaction
C₂H₆ (g) + aO₂ (g) ⟶ bCO₂ (g) + cH₂O (ℓ)
C : left 2, right b ⇒ b=2
H: left 6, right 2c⇒ 2c=6⇒ c= 3
O : left 2a, right 2b+c⇒ 2a=2b+c⇒2a=2.2+3⇒2a=7⇒a=7/2
A foam square has a mass of 25 g and a volume of 90 mL. What is the density?
Answer:
The answer is 0.28 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
So we have
[tex]density = \frac{25}{90} = \frac{5}{18} \\ = 0.277777...[/tex]
We have the final answer as
0.28 g/mLHope this helps you
Draw a structural formula for the alkene you would use to prepare the alcohol shown by hydroboration/oxidation.
Answer:
See explanation
Explanation:
The question is incomplete because the image of the alcohol is missing. However, I will try give you a general picture of the reaction known as hydroboration of alkenes.
This reaction occurs in two steps. In the first step, -BH2 and H add to the same face of the double bond (syn addition).
In the second step, alkaline hydrogen peroxide is added and the alcohol is formed.
Note that the BH2 and H adds to the two atoms of the double bond. The final product of the reaction appears as if water was added to the original alkene following an anti-Markovnikov mechanism.
Steric hindrance is known to play a major role in this reaction as good yield of the anti-Markovnikov like product is obtained with alkenes having one of the carbon atoms of the double bond significantly hindered.
which balances the equation Mg + O2 → MgO
Answer:
2Mg+[tex]O_{2}[/tex]→2MgO
Explanation:
The first step is magnesium + oxygen equals magnesium oxide
The second step is changing that into an equation which looks like Mg+[tex]O_{2}[/tex]→MgO
The third step is to 2*Mg and 2*O as well as the product has to be 2*Mg,2*O which gets the equation to become balanced as 2Mg+[tex]O_{2}[/tex]→2MgO
The coefficient 2 balance the given reaction. The balanced equation for the given reaction is given as [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].
A balanced equation is a mathematical representation of a chemical reaction that respects the law of mass conservation. It depicts the reactants and products of the reaction, as well as the relative amounts of each species. The unbalanced equation is [tex]\rm Mg + O_2 \rightarrow MgO[/tex]. One magnesium (Mg) atom on the left side and one on the right side, so the magnesium is already balanced. Balance the oxygen (O) atoms. On the left side, there are two oxygen (O) atoms present in the O2 molecule. On the right side, there is only one oxygen (O) atom in the MgO molecule. To balance the oxygen atoms, we need to add a coefficient of 2 in front of MgO: [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex]. The balanced equation is [tex]\rm Mg + O_2 \rightarrow 2MgO[/tex].
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A metal block, 2.0cm x 2.5cm x 3.0cm, has a mass of 40.5g. What is the density of the sample? What type of metal is the metal block composed of?
Aluminum - 2.699
Copper - 8.92
Iron - 7.874
Lead - 11.43
Nickel - 8.908
Tin - 7.265
Zinc - 7.14
Answer:
The block is made up of aluminum.
density = 2.7 g/cm³
Explanation:
Given data:
Dimension of metal block = 2.0 cm×2.5 cm× 3.0 cm
Mass of block = 40.05 g
Density of block = ?
Which metal is this = ?
Solution:
Density:
Density is equal to the mass of substance divided by its volume.
The symbol used for density is called rho. It is represented by ρ. However letter D can also be used to represent the density.
Units:
SI unit of density is Kg/m3.
Other units are given below,
g/cm3, g/mL , kg/L
Formula:
D=m/v
D= density
m=mass
V=volume
Volume of block = 2.0 cm×2.5 cm× 3.0 cm = 15 cm³
d = m/v
d = 40.5 g/ 15 cm³
d = 2.7 g/cm³
The block is made up of aluminum.
Does anybody understand this I’m stuck
Answer:
it's the first one
Explanation:
can you help me too
PLZ ANSWER WILL GIVE BRAINLIEST ASAP
Given the data below, what substance does not show a reaction for any of the tests? Hint: (+)= reaction occurred, (-)= no reaction
unknown
salt
Corn starch
Gelatin
Answer:
Salt
Explanation:
It has all -
Calculate the density of an object with mass = 30.50 g and a volume = 2.20 cm^3
Answer:
The answer is 13.86 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass = 30.5 g
volume = 2.2 cm³
We have
[tex]density = \frac{30.5}{2.2} \\ = 13.863...[/tex]
We have the final answer as
13.86 g/cm³Hope this helps you
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Click Oil Basics and use the information to complete this passage that discusses how plastic production affects society.
The production of plastics makes life
{answer} , so it benefits society. On the other hand, the production of plastics causes air and water {answer} , so it also harms society.
Answer:
easier and pollution
Explanation:
I just had this question and got it right
1. An atom has 57 neutrons and 42 protons. How many electrons will this atom have if it
neutral?
57
44
42
40
Answer:
42
Explanation:
Because the proton number or atomic number is equal to electron number.
Answer:
42
In order for it to be neutral there must be the same amount of protons and neutrons
Have a nice day! :)
Which statement best defines potential enregy?
A. Potential energy is stored energy.
B. Potential energy is energy that can change over time.
C.Potential energy is the energy of motion.
D. Potential energy is the type of energy a roller coaster uses.
Answer:
A. Potential energy is stored energy
Explanation:
Answer:
A
Explanation:
i have the same question
Identify the law that explains the following observation:
Nitrogen Dioxide can be formed by reacting 14 grams of
nitrogen with 32 grams of oxygen.
Answer:
Proust's law of definite proportion
Explanation:
The law of constant proportion states that the components elements of a given chemical compound combine with each other in a fixed mass ratio when the compound is produced by any given process
Therefore, from the question, the chemical formula for Nitrogen Dioxide is NO₂, where the molar mass of nitrogen, N = 14
The molar mass of oxygen, O = 16
Given that one molecule of NO₂, contains one atom of nitrogen and two atoms of oxygen, one mole of NO₂ will contain 14 grams of nitrogen and 32 grams of oxygen, according to Proust's law of definite proportion.
What is the volume, in liters, of 1.40 mol of oxygen gas at 20.0°C and 0.974 atm?
Answer:
V = 34.55 L
Explanation:
Given that,
No of moles, n = 1.4
Temperature, T = 20°C = 20 + 273 = 293 K
Pressure, P = 0.974 atm
We need to find the volume of the gas. It can be calculated using Ideal gas equation which is :
PV=nRT
R is gas constant, [tex]R=0.08206\ L-atm/mol-K[/tex]
Finding for V,
[tex]V=\dfrac{nRT}{P}\\\\V=\dfrac{1.4\times 0.08206\times 293}{0.974 }\\\\V=34.55\ L[/tex]
So, the volume of the gas is 34.55 L.
pls help ill mark as brainliest :)
Q7. Pb + O2 PbO2
Is this combustion, single replacement, double replacement, synthesis, or decomposition
Answer:
This is a synthesis reaction.
Explanation:
Two elements are bonded together to form (synthesize) a new compound.
• True False estion 2 (1 point) Water and ice are made from the same molecule H2O True False
Answer:
true i think
Explanation:
A piece of wood that measures 2.7 cm x 5.5 cm x 3.9 cm has a mass of 84 g what is the density of the wood
The density of the wood : 1.45 g/cm³
Further explanationDensity is a quantity derived from the mass and volume
Density is the ratio of mass per unit volume
With the same mass, the volume of objects that have a high density will be smaller than objects with a smaller type of density
The unit of density can be expressed in g/cm³ or kg/m³
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
Volume of the wood[tex]\tt V=2.7\times 5.5\times 3.9=57.915~cm^3[/tex]
density[tex]\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{84~g}{57.915~cm^3}=\boxed{\bold{1.45`g/cm^3}}[/tex]
How many total atoms of element X are represented below?
I hate chemistry please help
Answer:
Love it because Love it
Explanation:
Two liters of hydrogen gas are stored at a
pressure of 100 kPa. If the temperature
does not change, what will the volume
of the gas be when the pressure is
decreased to 25 kPa?
Answer:
the volume will expand
Explanation:
gas under pressure contracts, and expands with a lesser pressure
The volume of the hydrogen gas at 25 kPa is 8 Liters.
Explanation:
Given:
At constant temperature, 2 liters of hydrogen gas at 100kPa pressure.
To find:
The volume of the hydrogen gas at 25kPa.
Solution:
The initial pressure of the hydrogen gas =[tex]P_1=100 kPa[/tex]
The initial volume of the hydrogen gas at 100 kPa =[tex]V_1=2 L[/tex]
The final pressure of the hydrogen gas =[tex]P_2=25 kPa[/tex]
The final volume of the hydrogen gas at 25kPa = [tex]V_2=?[/tex]
Using Boyles law:
[tex]P_1V_1=P_2V_2\\100kPa\times 2 L=25 kPa\times V_2\\V_2=\frac{100 kPa\times 2L}{25 kPa}=8L[/tex]
The volume of the hydrogen gas at 25 kPa is 8 Liters.
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Consider the reaction below. 2 Upper N Upper H Subscript 3 (g) Baseline double headed arrow Upper N Subscript 2 (g) Baseline + 3 Upper H Subscript 2 (g). What is the most likely effect to the forward reaction if there is an increase in pressure on this reaction? The reactant surface area increases. The reaction rate decreases. The reaction is not affected at all. The reaction stops completely.
Answer:
The increase in pressure of the reacting system will increase the formation of NH₃
Explanation:
The given parameters are;
2NH₃ (g) ⇄ N₂ (g) + 3H₂ (g)
The number of molecules in the reactant side of the equation = 2 molecules
The number of molecules in the product side of the equation = 1 + 3 = 4 molecules
Avogadro's law states that equal volume of all gases at a given temperature and pressure contains equal number of molecules
Therefore, given that the number of molecules of the product are twice the number of molecules of the reactant, the volume of the product is twice the volume of the reactant
If the pressure is increased, at constant temperature by Boyles law, the volume will be reduced, favoring the formation of the low volume occupying NH₃
Therefore, the reverse reaction (formation of NH₃) will preferably occur.
Answer:
The answer is B
Explanation:
The other answer is incorrect. The correct Answer is B
Trust Me
Explain how the igneous rock granite forms. Then tell how the granite might become the sedimentary rock sandstone and then the metamorphic rock quartzite.
Answer:
There are three main types of rocks: sedimentary, igneous, and metamorphic. Each of these rocks are formed by physical changes—such as melting, cooling, eroding, compacting, or deforming—that are part of the rock cycle. Sedimentary Rocks Sedimentary rocks are formed from pieces of other existing rock or organic material. There are three different types of sedimentary rocks: clastic, organic (biological), and chemical. Clastic sedimentary rocks, like sandstone, form from clasts, or pieces of other rock. Organic sedimentary rocks, like coal, form from hard, biological materials like plants, shells, and bones that are compressed into rock. The formation of clastic and organic rocks begins with the weathering, or breaking down, of the exposed rock into small fragments. Through the process of erosion, these fragments are removed from their source and transported by wind, water, ice, or biological activity to a new location. Once the sediment settles somewhere, and enough of it collects, the lowest layers become compacted so tightly that they form solid rock. Chemical sedimentary rocks, like limestone, halite, and flint, form from chemical precipitation. A chemical precipitate is a chemical compound—for instance, calcium carbonate, salt, and silica—that forms when the solution it is dissolved in, usually water, evaporates and leaves the compound behind. This occurs as water travels through Earth’s crust, weathering the rock and dissolving some of its minerals, transporting it elsewhere. These dissolved minerals are precipitated when the water evaporates. Metamorphic Rocks Metamorphic rocks are rocks that have been changed from their original form by immense heat or pressure. Metamorphic rocks have two classes: foliated and nonfoliated. When a rock with flat or elongated minerals is put under immense pressure, the minerals line up in layers, creating foliation. Foliation is the aligning of elongated or platy minerals, like hornblende or mica, perpendicular to the direction of pressure that is applied. An example of this transformation can be seen with granite, an igneous rock. Granite contains long and platy minerals that are not initially aligned, but when enough pressure is added, those minerals shift to all point in the same direction while getting squeezed into flat sheets. When granite undergoes this process, like at a tectonic plate boundary, it turns into gneiss (pronounced “nice”). Nonfoliated rocks are formed the same way, but they do not contain the minerals that tend to line up under pressure and thus do not have the layered appearance of foliated rocks. Sedimentary rocks like bituminous coal, limestone, and sandstone, given enough heat and pressure, can turn into nonfoliated metamorphic rocks like anthracite coal, marble, and quartzite. Nonfoliated rocks can also form by metamorphism, which happens when magma comes in contact with the surrounding rock. Igneous Rocks Igneous rocks (derived from the Latin word for fire) are formed when molten hot material cools and solidifies. Igneous rocks can also be made a couple of different ways. When they are formed inside of the earth, they are called intrusive, or plutonic, igneous rocks. If they are formed outside or on top of Earth’s crust, they are called extrusive, or volcanic, igneous rocks. Granite and diorite are examples of common intrusive rocks. They have a coarse texture with large mineral grains, indicating that they spent thousands or millions of years cooling down inside the earth, a time course that allowed large mineral crystals to grow.
Alternatively, rocks like basalt and obsidian have very small grains and a relatively fine texture. This happens because when magma erupts into lava, it cools more quickly than it would if it stayed inside the earth, giving crystals less time to form. Obsidian cools into volcanic glass so quickly when ejected that the grains are impossible to see with the naked eye. Extrusive igneous rocks can also have a vesicular, or “holey” texture. This happens when the ejected magma still has gases inside of it so when it cools, the gas bubbles are trapped and end up giving the rock a bubbly texture. An example of this would be pumice.
Explanation:
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