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laila [671]
3 years ago
8

When heat energy is added two changes are observed: Change A: solid changes phases to a liquid Change B: liquid changes phases t

o a gas What are the names or phase changes in A and B
Chemistry
2 answers:
AlexFokin [52]3 years ago
8 0
A is melting. Melting occurs when the molecules of a solid speed up enough that the motion overcomes the attractions so that the molecules can move past each other as a liquid.

b is evaporation The molecules move and vibrate so quickly that they escape into the atmosphere as molecules of water vapor
Scilla [17]3 years ago
8 0

Answer:

C) A is melting and B is evaporation.

Explanation:

Solids turn to liquids at high temperatures, and same thing with liquids turning into gases.

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Use the ideal gas law to calculate the concentrations of nitrogen and oxygen present in air at a pressure of 1.0 atm and a tempe
notka56 [123]

Answer:

[N₂] = 0.032 M

[O₂] = 0.0086 M

Explanation:

Ideal Gas Law → P . V = n .  R . T

We assume that the mixture of air occupies a volume of 1 L

78% N₂ → Mole fraction of N₂ = 0.78

21% O₂  → Mole fraction of O₂ = 0.21

1% another gases  → Mole fraction of another gases = 0.01

In a mixture, the total pressure of the system refers to total moles of the mixture

1 atm . 1L = n . 0.082L.atm/mol.K . 298K

n = 1 L.atm / 0.082L.atm/mol.K . 298K → 0.0409 moles

We apply the mole fraction to determine the moles

N₂ moles / Total moles = 0.78 → 0.78 . 0.0409 mol = 0.032 moles N₂

O₂ moles / Total moles = 0.21 → 0.21 . 0.0409 mol = 0.0086 moles O₂

4 0
3 years ago
Select all
Schach [20]

Answer: The correct option is option d

Explanation - The mean deal with science is that it allows people to carry on research in an organized manner to find or make new discoveries and inventions.  

The basic purpose of science is to try new things or ways to get an outcome by constant perseverance on research and negating the ways that don't work thus giving and improving knowledge of what is correct and what is not to make a new Discovery or invention.  

7 0
3 years ago
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What is the total enthalpy change for the reaction? Is the reaction exothermic or endothermic?
Nuetrik [128]

Answer: S8(s) + 8O2(g) → 8SO2(g) ΔH = -2368 kJ a.

8 0
3 years ago
Is each of these statements true? If not, explain why.(m) For most reactions, ΔH°rnx is lowered by a catalyst.
barxatty [35]

A  catalyst reduces H°rnx in most reactions. The answer is false

<h3>Do catalysts reduce delta H?</h3>

By reducing the activation energy required for the reaction to occur, a catalyst just modifies the route used to go from reactants to products. However, because it doesn't alter the state of the products or reactants, delta H is unaffected.

A catalyst reduces a reaction's activation energy, enabling a chemical reaction to occur. The number of reactant particles with energy above the activation energy increases as the temperature of a reaction rises.

learn more about catalyst refer

brainly.com/question/12507566

#SPJ4

3 0
1 year ago
I need help with #10 (a,b and c) please and thank you!
Sidana [21]

a. An oxidation reaction. An oxidation reaction is a type of chemical reaction that involves a transfer of electrons between two species.

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