Honors Chemistry Gas Laws

1. In the formula, PV=nRT, the variable n is measured in what unit

Grams

K

KPa

Molecules

Moles

The variable "n" in the formula PV=nRT represents the number of moles. Moles is a unit of measurement used in chemistry to quantify the amount of a substance. It is a convenient unit because it allows for the comparison of different substances based on their molecular weights. Therefore, in the given formula, "n" is measured in moles.

Explanation

The variable "n" in the formula PV=nRT represents the number of moles. Moles is a unit of measurement used in chemistry to quantify the amount of a substance. It is a convenient unit because it allows for the comparison of different substances based on their molecular weights. Therefore, in the given formula, "n" is measured in moles.

2. Chemistry is
(the answer is e)

Awesome

Challenging but awesome

Really cool

Fun

All of the above

This question is asking for a description of chemistry. The answer "all of the above" suggests that chemistry is all of the options listed - awesome, challenging but awesome, really cool, and fun. In other words, chemistry is considered to be an amazing subject that can be both challenging and enjoyable.

Explanation

This question is asking for a description of chemistry. The answer "all of the above" suggests that chemistry is all of the options listed - awesome, challenging but awesome, really cool, and fun. In other words, chemistry is considered to be an amazing subject that can be both challenging and enjoyable.

3. The relationship between two variables would be if an increase in one, resulted in an increase in the other

The answer "direct, directly proportional, proportional" is correct because all three terms describe a relationship between two variables where an increase in one variable leads to an increase in the other variable. These terms can be used interchangeably to indicate that the variables change in the same direction and at a consistent rate.

Explanation

The answer "direct, directly proportional, proportional" is correct because all three terms describe a relationship between two variables where an increase in one variable leads to an increase in the other variable. These terms can be used interchangeably to indicate that the variables change in the same direction and at a consistent rate.

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5. Which set of variables exhibits a direct relationship?

P , V

V , T

When V increases T increases , but when P increases V decreases

Explanation

When V increases T increases , but when P increases V decreases

6. The is the quotient of the number of moles of a substance in a sample, divided by the total number of moles in the sample.

good to know what its called but more important to know that its used in determining partial pressure.(when you multiply the mole fraction by the total pressure)

Explanation

good to know what its called but more important to know that its used in determining partial pressure.(when you multiply the mole fraction by the total pressure)

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7. Real gases resemble ideal gases at pressure

low pressure means a greater distance between particles, making the gas act more like an ideal gas

Explanation

low pressure means a greater distance between particles, making the gas act more like an ideal gas

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8. 1 mole of any gas at any pressure will always

Occupy 22.4L of space

Contain 6.02x10^23 molecules

Behave like an ideal gas

Exert 101.3kPa of pressure on its surroundings

B must always be true for the sample to be 1 mole of gas, all the other choices can vary with pressure

Explanation

B must always be true for the sample to be 1 mole of gas, all the other choices can vary with pressure

9. A 11.0mol mixture of gases at 108.2 kPa is composed of 3.00mol He, 2.00mol H₂, 3.50mol O₂, and 1.50mol CO₂. What is the partial pressure of O₂?

81kPa

34.427kPa

34.4kPa

37.87kPa

37.9kPa

For calculating partial pressure you first find the mole ratio, in this case(3.50mol O2/10.0mol total), and then multiply by the total pressure to determine the pressure resulting from oxygen. Mind your significant figures.

Explanation

For calculating partial pressure you first find the mole ratio, in this case(3.50mol O2/10.0mol total), and then multiply by the total pressure to determine the pressure resulting from oxygen. Mind your significant figures.

10. Choose the false statement

Gases with a large mass diffuse quickly

Gases are very low density substances that interact with their surroundings through collisions

Volume of a gas can be increased at constant temperature by reducing pressure

Gases behave as ideal gases at all temperatures

This is a reference to the formula for relative rates of diffusion that shows larger mass means lower rates of diffusion, just remmber to write the formula down on the test and understand what the variables are.

Explanation

This is a reference to the formula for relative rates of diffusion that shows larger mass means lower rates of diffusion, just remmber to write the formula down on the test and understand what the variables are.

11. A system of gases is made up of 1.00mol CO₂ and 2.00mol O₂ at STP, which of the following changes would result in the system behaving more like an ideal gas?

An increase in pressure and a decrease in volume

A decrease in pressure and an increase in volume

An increase in temperature and an decrease in volume

An increase in temperature and an increase in volume

None, every gas is ideal at STP

Fairly simple ideal gas properties, increasing the volume decreases the pressure, decreased pressure and increased temperature reduce density bringing particles farther apart making them interact less.

Explanation

Fairly simple ideal gas properties, increasing the volume decreases the pressure, decreased pressure and increased temperature reduce density bringing particles farther apart making them interact less.

12. When a 1.00L sample of N2 at 43.0kPa and 1.00L sample of O2 at 29.4kPa are mixed in a 1.00L container what is the resulting total pressure.

72.4 kPa

71.2kPa

144.2kPa

13.6kPa

86kPa

To find the resulting total pressure when the two gases are mixed, we can use Dalton's Law of Partial Pressures, which states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each individual gas.

Mathematically, it can be represented as:

Total Pressure = Partial Pressure of N2 + Partial Pressure of O2

Given: Partial Pressure of N2 (P(N2)) = 43.0 kPa Partial Pressure of O2 (P(O2)) = 29.4 kPa

Total Pressure = 43.0 kPa + 29.4 kPa Total Pressure = 72.4 kPa

Explanation

To find the resulting total pressure when the two gases are mixed, we can use Dalton's Law of Partial Pressures, which states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each individual gas.

Mathematically, it can be represented as:

Total Pressure = Partial Pressure of N2 + Partial Pressure of O2

Given: Partial Pressure of N2 (P(N2)) = 43.0 kPa Partial Pressure of O2 (P(O2)) = 29.4 kPa

Total Pressure = 43.0 kPa + 29.4 kPa Total Pressure = 72.4 kPa

13. Air is a mixture of gases which is composed primarily of N₂, more specifically it is 76.5% N₂ by mass, if atmospheric pressure is 101.3kPa what is the partial pressure due to N₂

78kPa

77.5kPa

79.0kPa

101.3kPa

Not enough information

Even though you know the percentage N2 by mass, without knowing what else is in the system and how much of it there is, it is impossible to get the mole fraction of N2

Explanation

Even though you know the percentage N2 by mass, without knowing what else is in the system and how much of it there is, it is impossible to get the mole fraction of N2

14. Compared to the number of moles of O₂ there are in a sample the number of atoms in the sample

Is twice as much

Is 6.02x10^23 times larger

Is half as much

Is 1.204x10^24 times larger

Just as large

Okay so this one is a little tricky, but its actualy quite simple, for every mole there are 6.02x10^23 molecules and for every molecule there are two atoms. I just wanted to demonstrate how the question could be worded to make it harder than it really is.

Explanation

Okay so this one is a little tricky, but its actualy quite simple, for every mole there are 6.02x10^23 molecules and for every molecule there are two atoms. I just wanted to demonstrate how the question could be worded to make it harder than it really is.