When coal burns, the reaction

A. releases heat and is endothermic.

B. releases heat and is exothermic.

C. absorbs heat and is endothermic.

D. absorbs heat and is exothermic

Answers

Answer 1
Answer is B. Releases heat and is exothermic

Related Questions

A student wants to test an unknown chemical solution. What test should they perform to determine whether the chemical is an acid or base?


Or


Courtney wants to test an unknown chemical solution. What test should Courtney perform to determine whether the chemical is an acid or base?


A.

Test the solution by testing its conductivity


B.

Test the solution by increasing its temperature.


C.

Test the solution by tasting it.


D.

Test the solution's pH by using litmus paper.


The answer is D for whoever looked this up

Answers

Answer: D

Explanation:

The litmus paper will help determine the pH, and thus if it is an acid or a base.

A current of 3.46 A is passed through a Sn(NO3)2 solution for 1.40 h . How much tin is plated out of the solution?

Answers

Answer:

About 10.7 grams.

Explanation:

The reduction reaction is represented by:
[tex]\displaystyle \text{Sn}^{2+}_\text{(aq)} + 2e^- \longrightarrow \text{Sn}_\text{(s)}[/tex]

A current of 3.46 amperes (C/s) is passed through the solution for 1.40 hours. The total amount of charge is hence:
[tex]\displaystyle 1.40\text{ hour} \cdot \frac{3600\text{ s}}{1\text{ hour}}\cdot \frac{3.46\text{ C}}{1\text{ s}} = 1.74\times 10^4\text{ C}[/tex]

One mole of solid Sn is transferred per two moles of electrons. Hence, using Faraday's constant:
[tex]\displaystyle 1.74\times 10^4\text{ C} \cdot \frac{1\text{ mol e$^-$}}{96485\text{ C}} \cdot \frac{1\text{ Sn}}{2\text{ mol e$^-$}}\cdot \frac{118.71\text{ g Sn}}{1\text{ mol Sn}} = 10.7\text{ g Sn}[/tex]

In conclusion, about 10.7 grams of tin is plated out of the solution.

a gas has a temperature of 14C, and a volume of 4.5 liters. if the temperature is raised to 29C and the pressure is not changed, what is the new volume of the gas?

Answers

Answer: 4.7 L

Explanation:

15. What is the maximum pH an aqueous solution of 0.050 M Cu(NO3)2 can be adjusted to before a precipitate of Cu(OH)2 will form

Answers

The maximum pH an aqueous solution of 0.050 M Cu(NO3)2  is mathematically given as

pH=5.8

What is the maximum pH an aqueous solution of 0.050 M Cu(NO3)2 can be adjusted to before a precipitate of Cu(OH)2 will form?

Generally, the equation for the Chemical reaction  is mathematically given as

Cu(OH)2----><---Cu^2 +2OH-

Therefore

s^2=1.0*10^{-19}

s=3.16*10^{=9}

{OH-}=2s=6.3*10^10^{-19}

{H+}=10^{-14}/OH

{H+}=1.58*10^{-6}

In conclusion

pH=-log(1.58*10^{-6}

pH=5.8

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27.2g CuCl2 was dissolved in 2.50 L of the water. What is the molality of the solution?

Answers

Answer:

0.0800 (on CK-12)

Explanation:

Given grams of CuCl2/molar mass of CuCl2
27.2g/134.45g=0.2023...

Next,
0.2023mol/2.50L = 0.0800

The molality of the copper(II) chloride (CuCl₂) solution is 0.081 mol/kg

Molality

Molality is a measure of the number of moles of solute in a solution corresponding to 1 kg or 1000 g of solvent

First, we will determine the number of moles of CuCl₂ present

Using the formula,

[tex]Number\ of\ moles = \frac{Mass}{Molar\ mass}[/tex]

Mass of CuCl₂ = 27.2 g

Molar mass of CuCl₂ = 134.45 g/mol

∴ Number of moles of CuCl₂ present = [tex]\frac{27.2}{134.45 }[/tex]

Number of moles of CuCl₂ present = 0.2023 mole

Now, for the molality of the solution

Volume of solvent (water) = 2.50 L

Since the density of water = 1kg/L

Then, mass of the solvent (water) = 2.50 kg

[tex]Molality = \frac{Number\ of\ moles}{Mass\ of\ solvent}[/tex]

∴ Molality of the solution = [tex]\frac{0.2023}{2.50}[/tex]

Molality of the solution = 0.081 mol/kg

Hence, the molality of the solution is 0.081 mol/kg

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A d1 octahedral complex is found to absorb visible light, with the absorption maximum occurring at 509 nm. Calculate the crystal-field splitting energy, δ , in kj/mol

Answers

The crystal field theory accounts for the color of transition metal ions on the bases of splitting of d orbitals. The energy of the crystal-field splitting is 235kJ/mol.

What is crystal field splitting energy?

The crystal field theory accounts for the color of transition metal ions on the bases of splitting of d orbitals. The energy of the spliting is obtained from the wavelength in the visible spectrum.

Now the wavelength is  509 nm hence the energy is obtained from;

E = 6.6 * 10^-34 * 3 * 10^8/509 * 10^-9 * 6.02 * 10^23/1 mol * 1/1000 kJ

= 235kJ/mol

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How do elements differ going from left to right across a period on the periodic table?

please choose one
They become more valuable.

They become lighter.

They become more radioactive.

Their atomic number increases.

Answers

their atomic number increases

Based on the chemical equation, use the drop-down menu to choose the coefficients that will balance the chemical equation: ()zn ()hcl → ()zncl2 ()h2

Answers

Based on the chemical equation, to balance the given equation we should use 2 as a coefficients of HCl on reacatnt side of the reaction.

What is balanced equation?

Balanced chemical equations are those equation in which each entities are present in same amount on reactant side as well as on the product side of the chemical reaction.

Given chemical reaction is:

Zn + HCl → ZnCl₂ + H₂

In the above reaction equation  is not balanced as number of chlorine and hydrogen atoms are not equal on both sides, so balanced equation will be:

Zn + 2HCl → ZnCl₂ + H₂

Hence we add 2 as a coefficient of HCl to balance the equation.

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Answer:

1 2 1 1

Explanation:

What is the atomic symbol for an isotope with protons = 27 and atomic mass = 60?​

Answers

Answer:

Cobalt (Co)

Explanation:

it has 27 protons and atomic mass of 60 in Cobalt 60 isotope

A chemist is using a solution of hno3 that has a ph of 3.75. what is [h ] for the solution?

Answers

[tex]\text{pH} = -\log[H^{+}]\\\\\implies \log[H^{+}] = -\text{pH}\\\\\implies [H^{+}] = 10^{-\text{pH}}}\\\\\implies [H^{+}] =10^{-3.75}=0.00017~M[/tex]

Which of the following happens when a reaction reaches dynamic equilibrium in a closed system?
The concentrations of the reactants and products increase.
The concentrations of the reactants and products decrease.
The rate of the forward reaction equals the rate of the reverse reaction.
The rate of the forward reaction is slower than the rate of the reverse reaction.

Answers

Answer:

Option C

Explanation:

At equilibrium the reaction remains constantThe rate of forward reaction equals rate if backward reactionConcentration of products and reactants remains same

Answer:

The rate of the forward reaction equals the rate of the reverse reaction.

Explanation:

As ocean water salt concentration increases, the _____.

Question 1 options:

water density increases and rises to the top of the sea.


water density increases and sinks to the bottom of the sea.


water density decreases and rises to the top of the sea.


water density decreases and sinks to the bottom of the sea.

Answers

Answer:

B water density increases and rises to the top of the sea

Explanation:

i took a test and got it correct lol

If 25.0 g of NH₃ and 45.0 g of O₂ react in the following reaction, what is the mass in grams of NO that will be formed?
4 NH₃ (g) + 5 O₂ (g) → 4 NO (g) + 6 H₂O (g)

Answers

Answer:

44.2 g NO

Explanation:

Question is posted elsewhere, be sure to search before posting to save yourself some time :)

Hydrogen gas, oxygen gas, and water vapor are collected in eudiometer. The eudiometer contains 0.00206 g of hydrogen, 0.0811 g of oxygen, and 0.0151 g of water vapor. The total pressure is 1101.1 mmHg. Calculate the partial pressure (in mmHg) of hydrogen gas.

Answers

For the partial pressure in mmHg of hydrogen gas  is mathematically given as

partial p = 257.81mmHg

What is the partial pressure in mmHg of hydrogen gas?

Generally, the equation for the partial pressure is mathematically given as

partial p = mole of H2/total moles x total pressure

H2 =0.00206/2

H2 = 0.00103

O2 = 0.0811/32

O2 = 0.00253

H20 = 0.0151/18

H2O = 0.000839

total moles = 0.00103+0.000839+0.00253

total moles = 0.00439

therefore

partial p = 0.00103/0.00439 x 1101.1

partial p = 257.81mmHg

In conclusion, the partial pressure in mmHg of hydrogen gas is

partial p = 257.81mmHg

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Why Do Onions Make You Cry? Even better, know how to prevent the tears.

Answers

Answer:

The onion cells release compounds into the air, and enzymes must follow up to alter amino acids into other compounds, causing irritation in the eye. To prevent, "crying" from an onion, try peeling the onion, then chilling the onion in the fridge for about 30 minutes. Otherwise, you can buy tearless onions.

What is the origin of fahrenheit and centigrade temperature scales?.

Answers

Answer:

The 18th-century German physicist Daniel Gabriel Fahrenheit originally took as the zero of his scale the temperature of an equal ice-salt mixture

Explanation:

Which economical systems do you most agree with and why

Answers

Answer:

be specific it's too little information

What is the volume, in liters, of 12 moles of a gas at a temperature of 467.5 K at a pressure of 9.67 atmospheres?


P
V
=
n
R
T

R = 0.0821
a
t
m

L
m
o
l

K

Answers

Explanation:

From PV = nRT

9.67V = 12(0.0821)(467.5)

V = 47.63 L

a balloon is filled with 2 liters of air at sea level, then a scuba diver carries it under the ocean. if the scuba diver stops when the pressure on the balloon is 3 atmospheres, what is the new volume of the balloon? round to the nearest hundredth.
A. 0.67 liters
B. 1.5 liters
C. 6 liters
D. 5 liters ​

Answers

Answer:

The correct answer is C. 6 Liters

Explanation:

You have to multiply the 2 liters by the atmospheres (which is 3) you get 6. six liters is the new volume.

Is 18 karat gold a homogeneous mixture or heterogeneous mixture?

Answers

Answer:

Gold is an element. That means that it is the same all the way through and in an ideal state of purity contains nothing but gold atoms. Therefore it is not a mixture. In such a case it is as close to a uniform solid solution as may be, so it will be an homogeneous mixture.

Explanation:

really hope this helps :)

S8(s) +
Cu(s) →
CuS(s)
Which formula(s) represent the reactant(s)?
Which formula(s) represent the product(s)?
Name the compound Cu2S.
What type of reaction is shown by the chemical equation?
Balance the chemical equation and write the coefficients in the space provided.

Answers

Answer:

Ox2 Cu03

Explanation:All from plato definetley correct

A compound with the empirical formula CH 2 O has a formula mass of 180 g/mol. What is its molecular formula

Answers

Empirical formula mass

12+2(1)+1628+230g/mol

Molecular fornula mass:-180g/mol

n=Molecular formula mass/Empirical formula massm=180/30n=6

Molecular formula:-

n×Empirical formula6(CH_2OC_6H_12 O_6

how do you find the change in enthalpy on a potential energy diagram HELP MEEEE

Answers

LOL... I don't think my beautiful drawing helps a ton.

But basically in a potential energy diagram, the height distance between the reactants and products is the ∆H, aka the enthalpy change.

If the reactants are higher than products, then the reaction is exothermic.

If the products are higher than reactants, then the reaction is endothermic.

10. What is a battery an example of?

a. load b. switch c. energy source d. conductor

Answers

Answer:

an energy source

Explanation:

A student dissolves 15 grams
of salt in 250 mL of water.
What is the solute? What is
the solvent?

Answers

Answer:

salt is solute,water solvent, the mixture is the solition.

A student dissolves 15 grams of salt in 250 mL of water. The solute is salt and the solvent is water.

What is a solution?

A solution is a homogeneous mixture of one or more solutes dissolved in a solvent.

solvent: the substance in which a solute dissolves to produce a homogeneous mixturesolute: the substance that dissolves in a solvent to produce a homogeneous mixture

For solutions with components in the same phase, the substances present in lower concentration are solutes, while the substance present in highest abundance is the solvent.

Therefore, A student dissolves 15 grams of salt in 250 mL of water. The solute is salt and the solvent is water.

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Why does an aqueous solution of an ionic substance conduct an electric current?.

Answers

Answer:

Because ions in an aqueous solution are free to move independently from each other. the net flow of cations toward a negative or positive electrode results in a flow of charge, which is an electrical current.

Explanation:

The esophagus is a _______________ that passes food from your mouth to your ____________________. The stomach is the organ that ____________________ digestive juices to break down food.

Answers

Answer:

The answer is  Muscle, Stomach, chews or sucks.

Explanation:

These are the roles they play.

Which of these involves the formation of a new chemical substance?
Select one:
a. evaporation of gasoline
b. mixing salt and pepper
C. dissolving sugar in tea
d. rusting of an iron chain

Answers

Which of these involves the formation of a new chemical substance?

a. evaporation of gasoline

b. mixing salt and pepper

c. dissolving sugar in tea

d. rusting of an iron chain

[tex] \\ [/tex]

Answer:D. Rusting of an iron chain

[tex]__________[/tex]

A. Evaporation of gasoline

It does not form any chemical substance. Evaporation, is part of a physical change. Physical change only changes in its physical characteristics. Evaporation changes from liquid, to gas. Therefore, it is a physical change.

B. Mixing salt and pepper

No new substance formed. It does not form any chemical substance nor chemical change. When you mix salt and pepper, it only is a mixture wherein no new material can be form. Therefore, this is physical change as well.

C. Dissolving sugar in tea

When you dissolve sugar in your tea, it only changes the taste of the tea to sweet. Taste is part of the characteristic of physical change. It does not form any chemical substance nor chemical change. Therefore, this is physical change.

D. Rusting of an iron chain

Rusting is one of the common examples of chemical change in our daily lives. Rust is the new substance formed. However, this is considered as chemical change because this is irreversible or cannot be returned to its original substance/material. Finally, rusting of an iron chain involves the formation of new chemical substance.

Hence, the answer is D. Rusting of an iron chain.

By what process does thorium-230 decay to radium-226?.

Answers

Answer:

alpha emission

Explanation:

REEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE

Answers

C because the radiation of the sun comes down to earth and makes it hot

Answer:

c. sun, radiation

Explanation:

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