CHEMISTRY HIGH SCHOOL

The internal energy of a gas decreases by 1.65 kJ when it transfers 1.87 kJ of energy in the form of heat to the surroundings.(a) Calculate the work done by the gas on the surroundings.
(b) Does the volume of gas increase or decrease?

Answers

Answer 1
Answer:

The first law of thermodynamics states ΔU = q + w, where ΔU is the change in internal energy of a system, q is the heat entering or leaving the system (positive if it is entering the system, negative if it is leaving), and w is work done by the system or on the system (positive if work is being done on the system, negative if the system is doing work on its surroundings).

(a) The problem gives us the change in internal energy, ΔU, -1.65 kJ, as well as change in heat, -1.87 kJ (notice the negative, heat is leaving the system into the surroundings).

Therefore our equation is ΔU = q + p = -1.65 = -1.87 + w.

Solving for w gives us 0.22 kJ.

(b) As stated before, work positive if work is being done on the system and negative if the system is doing work on its surroundings since it represents energy in the form of work in the system. Doing work will transfer that energy out of the system making the sign negative, and having work done on the system transfers that energy into the system, making the sign positive.

Since the sign of 0.22 is positive, that means work is being done on the system by its surroundings. This means the volume of the gas will decrease. If work were negative, the volume would increase.

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Explain the iodine clock reaction.

Answers

Iodine clock reaction is a combination of hydrogen peroxide and sulfuric acid. When these are poured together, there is no reaction at first, but after time, a colored reaction will happen to the liquid and may change back to the original color. This idea was discovered by Hans Landolt in the late 1800s.

What causes the volume to change in gases? (choose all that apply) a) temperature
b) density
c) shape of container
d) pressure

Answers

Answer:

Temperature, pressure, shape of container

Answer:

temperature, density, pressure.

Explanation:

Which of the following is one way to prevent the corrosion of iron

Answers

A way to protect iron corrosion is to paint the Iron with layers of protective paint and coating.

Answer:

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Explanation:

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Is this true of false
PLEASE HELPP NO LINKSS

Answers

Answer:

That is true

Explanation:

:D

6. Explain why the boiling point of water is a characteristic physical property, but the temperature and volume of a glass of water are not.

Answers

The physical property is a physical characteristic of a substance at some given conditions

for example

The density of water is 1 g/ mL at STP

The boiling point of water is 373K at 1 atm pressure

so boiling point of water is its physical property. It does not change with amount of the substance. The boiling point of water will remain the same for 1g and 1kg etc

now temperature is an instant measurement, the temperature may vary from sample to sample. Some water sample can be cool or some can be hot. So we cannot define that temperature of all water sample at a given pressure will be the same.

similarly the volume is a not a physical property. It will change from amount to amount.

1g of water sample will have different volume and 100g of water will have different volume while the density of water will remain the same.

A physical property is a property that does not change the original substance, meaning that it does not break any bonds, nor for any new ones. Though, a physical property can be changing the substances state of matter. 

When you are boiling water, you are changing its state to go from a liquid to a gas. The temperature is not a characteristic physical property because it doesn't help us know a lot about that substance, in other words, it isn't significant to the substance. Same goes for volume. 
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