Chemistry Chapter 14
One cools a 465 mL gas sample at 55°C to standard temperature (0°C). What is its new volume? Please show your work) (V1/T1 = V2/T2)
(V1/T1 = V2/T2) Keep mL the same and convert celsius to kelvin and solve from there. the answer is 387.06 mL
One heats a gas sample of gas, originally at −39°C, to standard temperature (0°C), at which point one measures its pressure to be 808 mmHg. What was the original pressure of the gas? (Please show your work) (P1/T1 = P2/T2)
(P1/T1 = P2/T2) convert mmhg into atm and Celsius to Kelvin. Then solve from there. answer =0.91 atm
From a microscopic point of view, gas pressure is caused by the _________ of gas molecules on a surface.
collision (or collisions)
Gases occupy the volume of the _______________.
container
If the volume of a container is ___________, the gas molecules have less space to move around, causing the pressure to ____________.
decreased, increased
Real gases vary from the ideal gas laws gases at conditions of
low temperature and high pressure
One mixes 0.249 mol helium (He), 0.812 mol neon (Ne), and 0.429 mol argon (Ar) into a container at a total pressure of 1.340 atm. Calculate the partial pressure of each gas. (Please show your work) (P each gas = P total X (proportion of moles of gas)). Student must show work with their answer.
0.249 mol helium (He) + 0.812 mol neon (Ne) + 0.429 mol argon (Ar) = Ptotal= 1.490 total P He = 0.249 mol / 1.490 mol total = 0.167 P Ne = 0.812 mol / 1.490 mol total = 0.545 P Ar = 0.429 mol / 1.490 mol total = 0.288 P He = 1.340 X 0.167 = 0.224 P Ne = 1.340 X 0.545 = 0.730 P Ar = 1.340 X 0.288 = 0.386
__________ measures how much a given volume of matter decreases when placed under pressure.
Compressibility
______________ states that the total pressure of a mixture of gases is equal to the sum of all of the partial pressures of the component gases.
Dalton's law of partial pressure
___________ is the tendency of molecules to move from an area of high concentration to an area of low concentration until the concentration is uniform.
Diffusion
Three 1.0 liter flasks are filled with H2, O2, and Ne, respectively, at STP. Which of the following statements is true?
Each flask has the same number of gas molecules.
________________ is the process of a confined gas escaping through a tiny hole in its container.
Effusion
What is the ideal gas law?
If a fixed amount of ideal gas is kept at a fixed temperature, the pressure (P) and volume (V) are inversely proportional, that is, when one doubles, the other is reduced by half.
Under conditions of fixed temperature and amount of gas, Boyle's law requires that
PV = constant
The mathematical expression of the ideal gas law is __________. The variable "R" in the ideal gas law is the _________.
PV=nRT, ideal gas constant
How does the pressure of a confined gas respond when one decreases its volume?
The pressure will increase
A gaseous mixture of oxygen and nitrogen is maintained at a constant temperature. Which of the following MUST be true regarding the two gases?
Their average kinetic energies will be the same.
What is the new volume of a sample of neon if 5.23 L of the gas, originally at 214 kPa, and one compresses it until the pressure increases to 796 kPa? Please show your work) (P1V1 = P2V2)
This problem can be solved using Boyle's law:p1v1=p2v2 so 5.23*214=796*v2 v2=(5.23*214)/796=1.4L
An increase in the number of gas molecules in the same volume container _________ pressure.
increases
A(n) ___________ relationship means that as one variable increases in value, the other variable decreases. In a(n) __________ relationship, as one variable increases, so does the other variable.
inverse, direct
The pressure exerted by a mixture of gases is equal to the sum of pressure of each gas in case of ____________.
non-reacting gas
The ___________ of a gas (two words) is the contribution that one gas makes to the total pressure when the gas is part of a mixture.
partial pressure
There are four variables used to describe the condition of a gas. They are ________, _______, _________, and ________, as measured by the number of moles of gas particles (n).
pressure, volume, temperature, amount of the gas
Pressure is exerted by gases due to their ________.
random motion
How do scientists define temperature?
the average kinetic energy of all the atoms or molecules of that substance.
A hot-air balloon rises. Which is the best explanation for this observation?
the density inside the balloon is less than that of the surrounding air
A rigid metal tank contains helium gas. Which applies to the gas in the tank when some helium is removed at constant temperature?
the pressure of the gas decreases
A gas that is confined in a rigid container is heated. Which of the following statements is true?
the pressure will increase