1.
A system of gases is made up of 1.00mol CO_{2} and 2.00mol O_{2} at STP, which of the following changes would result in the system behaving more like an ideal gas?
Correct Answer
D. An increase in temperature and an increase in volume
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.
2.
A 11.0mol mixture of gases at 108.2 kPa is composed of 3.00mol He, 2.00mol H_{2}, 3.50mol O_{2}, and 1.50mol CO_{2}. What is the partial pressure of O_{2}?
Correct Answer
C. 34.4kPa
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.
3.
Choose the false statement
Correct Answer
A. Gases with a large mass diffuse quickly
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.
4.
1 mole of any gas at any pressure will always
Correct Answer
B. Contain 6.02x10^23 molecules
Explanation
B must always be true for the sample to be 1 mole of gas, all the other choices can vary with pressure
5.
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.
Correct Answer
A. 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
6.
Which set of variables exhibits a direct relationship?
Correct Answer
B. V , T
Explanation
When V increases T increases , but when P increases V decreases
7.
In the formula, PV=nRT, the variable n is measured in what unit
Correct Answer
E. 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.
8.
Compared to the number of moles of O_{2} there are in a sample the number of atoms in the sample
Correct Answer
D. Is 1.204x10^24 times larger
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.
9.
Air is a mixture of gases which is composed primarily of N_{2}, more specifically it is 76.5% N_{2} by mass, if atmospheric pressure is 101.3kPa what is the partial pressure due to N_{2}
Correct Answer
E. Not enough information
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
10.
Chemistry is
(the answer is e)
Correct Answer
E. All of the above
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.
11.
Real gases resemble ideal gases at pressure
Correct Answer
low
small
Explanation
low pressure means a greater distance between particles, making the gas act more like an ideal gas
12.
The relationship between two variables would be if an increase in one, resulted in an increase in the other
Correct Answer
direct
directly proportional
proportional
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.
13.
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.
Correct Answer
mole fraction
mole ratio
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)
14.
Avogadro's number (6.02x10^23), is the number of that make up one mole of a substance.
Correct Answer
molecules
particles
Explanation
this is just a simple recap of what the number means
15.
This is just for feedback, so feel free to write what you thought about the quiz. (length, difficulty, wording)