Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Chem unit 3
| Question | Answer |
|---|---|
| What is Dalton’s law of partial pressure? | in a mixture of non-reacting gases, the total pressure is equal to the sum of the partial pressures of each individual gas |
| What is mole fraction? | it is the ratio of the number of moles of a particular substance to the total number of moles of all substances in the mixture |
| What are three characteristics of mole fraction? | 1. The mole fraction of any component in a mixture must always be less than 1. 2. The sum of the mole fractions of all components in a mixture must be equal to 1. 3. Mole fraction is a dimensionless value. |
| Why isn’t gas collected over water pure? | because it mixes with water vapor |
| What is vapor pressure? | pressure exerted by the vapor of a substance when it is in equilibrium with its liquid or solid form in a closed system - represents the tendency of a substance to evaporate |
| How is vapor pressure affected by temperature? | vapor increases as temp rises because more molecules have enough kinetic energy to overcome intermolecular forces and escape the vapor phase |
| Briefly describe the molecular bases of gas pressure and compressibility | gas pressure arises from the collisions of gas particles with the walls of their container, eventually adding up to the total pressure |
| compressibility of gases | due to the large spaces between gas particles, which allows them to be pushed closer together under increased pressure |
| collision frequency | number of times gas particles collide with the walls of the container per unit of time |
| Briefly describe the molecular basis of Boyle’s law | states that the pressure of a gas is inversely proportional to its volume at a constant temperature |
| Briefly describe the molecular basis of Avogadro’s law | at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles (or particles) of the gas |
| Briefly describe the molecular basis of Dalton’s law of partial pressure | states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas in the mixture |
| Briefly describe the molecular basis of Charles’s law | that the volume of a gas is directly proportional to its temperature (in Kelvin) at constant pressure. |
| What is the relationship between average kinetic energy and temperature? | As temperature increases, particles move faster because their average kinetic energy increases |
| Write the equation for calculating kinetic energy from mass and velocity | KE equals ½ mv2 where m is the mass in kg and v is the velocity in m/s |
| If two objects have the same kinetic energy, but different masses, which object has the fastest speed? | the smaller object will have faster speed because to have the same kinetic energy, the smaller object must have more velocity |
| What is root-mean-square speed? | measure of the average speed of particles in a gas, considering the distribution of particle speeds. |
| What is the relationship between root-mean-square speed and molar mass? | the rms speed decreases as the molar mass increases |
| What is the relationship between root-mean-square speed and temperature? | the rms speed increases as the temperature increases |
| diffusion | diffusion is the process by which gas molecules spread out and mix with other gases due to random motion |
| effusion | effusion is the process by which gas molecules escape through a small hole or opening into a vacuum or another container |
| What is mean by free path? | average distance a gas molecule travels between collisions with other molecules |
| How is mean free path related to pressure? | the mean free path is inversely proportional to the pressure of the gas; lower pressure = less collisions, increase mean free path; high pressure = more collisions, decrease mean free path |
| What is the relationship between molar mass and the rate of effusion? | the rate of effusion of a gas is inversely proportional to the square root of its molar mass |
| What is Graham’s law of effusion? | states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass aka the heavier the molar mass, the slower the rate of diffusion |
| What are the two factors that must be taken into consideration to describe the behavior of a real gas? | intermolecular forces and molecular volume |
| Although the volume term in the ideal gas equation is taken as the volume of the container, what does the volume term actually represent? | free space available for gas molecules to move around |
| What happens to the volume of free space inside the container as the number of molecules inside the container increases? | volume of free space available for the molecules to move around decreases |
| What happens to the volume of free space inside the container as the size of the molecules increases? | volume of free space inside the container decreases b/c bigger molecules take up more space |
| ideal gas behavior | no intermolecular forces, particles have no volume, collisions are elastic (don't lose energy), and motion is random |
| Explain how the intermolecular forces within a gas sample effects pressure | attractive forces lower pressure and repulsive forces increase pressure at high densities |
| Is the real pressure typically greater or less than the ideal pressure? | less than the ideal pressure |
| Under what conditions is gas most ideal | under low atm (pressure) and high temp |
| What is the van der Waals equation. Define the terms | (P+ a (n/v) squared)) (V−nb)=nRT P= pressure V = volume n = # of moles R = gas constant (0.0821) T= temperature in Kelvin |
Created by:
user-1972564