Chemistry: Chapters 13 & 14
What is the ideal gas constant?
(R) 8.31 (L*kPa)/(K*mol)
What are the three assumptions of kinetic theory as it applies to gases?
-The particles in a gas are consiered to be small, hard spheres with an insignificant volume. -The motion of the particles in a gas is rapid, constant, and random. -All collisions between particls in a gas are perfectly elastic.
What temperature does the motion of particles cease?
0 Kelvin or -273.15 C
What is the relationship between atmosphere, mm Hg and kPa?
1 atm = 760 mm Hg = 101.3 kPa
What is a barometer?
A device used to measure atmospheric pressure.
What is a phase diagram?
A diagram that gives the conditions of temperature and pressure at which a substance exists as a solid, liquid, or vapor (gas).
What is effusion?
A gas escapes through a tiny hole in its container.
What is the aimless path that molecules take called?
A random walk.
What happens if the pressure in a sealed container is lower than outside pressure?
Air will rush into the container when opened which causes the woosh sound you her when oening vaccum packed things.
What is the kinetic theory?
All matter consists of tiny particles that are in constant motion.
What is a vacuum?
An empty space with no particles and no pressure.
An increase in kinetic energy results in what?
An increase in temperature.
How does pressure affect temperature?
As temperature goes up, the pressure goes up.
How are the pressure and temperature of a gas related?
As the temperature of an enclosed gas increases, the pressure increases if the volume is constant.
How are the temperature and volume of a gas related?
As the temperature of an enclosed gas increases, the volume increases if the pressure is constant.
What is John Dalton's law of partial pressures?
At constant volume and temperature, the total pressure exerted by a mixtrue of gases is equal to the sum of partial pressures of the component gases.
How can you raise the pressure exerted by a contained gas?
By reducing its volume.
What is the relationship between evapotion and kinetic energy?
During evaporation, only those molecules with a certain minimum kinetic energy can escape from the surface of a liquid.
What is Boyle's Law?
For a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure.
How does kinetic theory explain gas pressure?
Gas pressure is the result of billions of rapidly moving particles in a gas simultaneously colliding with an object.
Why are gases easier to compress than solids or liquids?
Gases are easily compressed because of the space between the particles in a gas.
How does the molar mass of a gas affect the rate at which the gas diffuses or effuses?
Gases of a lower molar mass diffuse and effuse faster than gases of higher molar masses.
Why does liquid evaporate faster when heated?
Heat --> more kinetic energy --> ones with more kinetic energy evaporate more.
What does volatile mean?
How easily it evaporates.
What is the combined Gas Law?
IT contains Boyles Law, Charle's Law and Gay - Lussas
How are the pressures and volumes of a gas related?
If the temperature is constant, as the pressure of a gas increases, the volume decreases.
How is the total pressure of a gas mixture related to the partial pressures of the component gases?
In a mixture of gases, the total pressure is the sum of the partial pressures of the gases.
Why are liquids and solids known as condensed states of matter?
Increasing the pressure on them has close to no effect on its volume.
What happens to vapor pressure as the temperature in a container increases?
It increases.
What is gas pressure? And what causes it?
It results from the force exerted by a gas per unit surface area of an object. Moving bodies exert a force when they collide but its small. This can build up when a lot of bodies collide.
What happens to boiling point and melting point with an increase in pressure?
It will raise the boiling point and lower the melting point.
What is an elastic collision?
Kinetic energy is transferred without loss from one particle to another.
What is the key difference between liquids and gases?
Liquids have an attraction that allow them have a definite volume.
What are the particles in a gas usually called?
Molecules or atoms.
What does the word kinetic refer to?
Motion
What is the formula concerning volume and pressure changes?
P1 x V1 = P2 x V2
What is the ideal gas law?
PV=nRT
What is Si unit of pressure?
Pascal (Pa)
What are the four generally variables used to describe a gas?
Pressure (P) in kilopascals, volume (V) in liters, temperature (T) in kelvins, and the number of moles (n).
Under what conditions are real gases most likely to differ from ideal gases?
Real gases differ from an ideal gas at low temperatures and high pressures.
What path do gas particles move in?
Straight line.
When can sublimation occur?
Sublimation occurs in solids with vapor pressures that exceed atmospheric pressure at or near room temperature.
What are the three factors that attract gas pressure?
The amount of gas, the volume, and the temperature are factors that affect gas pressure.
What is the normal boiling point?
The boiling point of a liquid at a pressure of 101.3 kPa.
What is sublimation?
The change of a substance from a solid to a vapor without passing through the liquid state.
What is atmospheric pressure?
The collisions of atoms and molecules in air with objects.
How are the conditions at which the phases are in equilibrium represented on a phase diagram?
The conditions of pressure and temperature at which two phases exist in equilibrium are indicated on a phase diagram by a line separating the two regions representing the phases.
What is partial pressure?
The contribution each gas in a mixture makes to the total pressure.
What is vaporization?
The conversion of a liquid to a gas or vapor.
What is kinetic energy?
The energy a object has because of its motion.
How are the structure and the properties of solids related?
The general properties of solids reflect the orderly arrangement of their particles and the fixed locations of their particles.
How does sweat cool you?
The heated particles evaporate leaving the cool ones behind.
What factors determine the physical properties of a liquid?
The interplay between the disruptive motions of particles n a liquid and the attractions among the particles determines the physical properties of liquids.
What is compressibility?
The measure of how much the volume of matter decreases under pressure.
What is the triple point?
The only set of conditions at which all three phases can exist at equilibrium with on another.
What happens under increased pressure to gases?
The particles are forced closer together or compressed.
What happens when a solid is heated?
The particles get more kinetic energy and began to move turning into a liquid.
What Gay-Lussac's law?
The pressure of a gas is directly proportional to the Kelvin temperature if the volume remains constant.
What is standard atmosphere?
The pressure require to support 760 mm of mercury in a mercury barometer at 35C.
What is Graham's law of effusion?
The rate of effusion of a gas is inversely proportional to the square root of the gas's molar mass.
What is the melting point?
The temperature at which a solid changes into a liquid?
What is the boiling point?
The temperature at which the vapor pressure of the liquid is just equal to the external pressure on the liquid.
What is the relationship between the temperature in kelvins and the kinetic energy of particles?
The temperature of a subtance is directly proportional to the average kinetic energy of the particles of the substance.
What is diffusion?
The tendency of molecules to move toward areas of lower concentration until the concentration in uniform throughout.
What is vapor pressure?
The vaporized water molecules that form against the container.
What is Charles law?
The volume of a fixed mass of gas is directly proportional to its Kelvin temperature if the pressure is kept constant.
What is evaporation?
Vaporization at the surface of a liquid that is not boiling.
What does atmospheric pressure depend on?
Weather and altitude.
What is potential energy?
When a substance is heated, the particles absorb and store some energy. The stored energy is potential.
How are the pressure, volume and temperature of a gas related?
When only the amount of gas is constant, the combined gas law describes the relationship among pressure, volume and temperature.
Are the temperatures for melting and freezing point the same?
Yes.
Is the space between gas particles empty? Are there attractive or repulsive forces?
Yes. No.
How can you calculate the amount of a contained gas when the pressure, volume, and temperature are specified?
You can use the ideal gas law to calculate the number of moles of the gas.
What are ideal gases?
gases that conform to the gas laws.
What does a manometer do?
measure the vapor pressure of a liquid.
What is the freezing point?
temperature at which a liquid changes into a solid.