Phase Changes
Heating Curves
Pressure, Volume, Temperature, and Amount of Gas
Gas Laws - Math Questions
Ideal Gas Law - Math Questions
100
What phase of matter is pictured below?
Gas (particles are far apart and moving fast)
100
What phase(s) are present for line AB?
Just solid
100
Which graph represents a direct relationship and an inverse relationship?
100
If a gas is at STP, what is the pressure and temperature of that gas?
The gas would be at 1 atm and 273K
100
What units are necessary for P, V, n, and T in the ideal gas law equation?
P = atm
V = L
n = mol
T = K
200
What is the phase change called when going from right to left?
Condensation (gas to liquid)
200
What is the freezing point of sodium chloride?
What is the melting point of sodium chloride?
Both freezing point and melting point are the same: 801oC
200
Which graph represents the relationship between pressure and volume?
Which graph represents the relationship between pressure and temperature?
Pressure and volume: inverse relationship
Pressure and temperature: direct relationship
200
A balloon starts with a pressure of 100 kPa and a volume of 100 mL and is compressed to a pressure of 200 kPa and a volume of 50 mL. The temperature of the balloon stays the same from beginning to the end. What happens to the number of gas particles in the balloon?
The number of gas particles will stay the same even though the pressure and volume are changing.
200
Convert 880 mmHg to atm.
1.16 atm
300
What is the phase change called when going left to right? Is this phase change endothermic or exothermic?
Melting (solid to liquid)
Endothermic (liquid particles have more energy than solid which means that energy was added)
300
What is happening during BC? Is it a phase change or increasing in temperature?
Phase change (phase changes are horizontal lines; increasing temperature are diagonal lines)
300
If the pressure of a gas increases and temperature remains constant, what should happen to the volume of the gas?
Pressure increases, volume DECREASES
300
A 25 L sample of gas at 373 K is cooled to 250 K. What is the new volume if the pressure is constant?
16.76 L
300
Convert 1.2 moles of nitrogen gas to grams of nitrogen gas.
33.62 g N2
400
What is the phase change called when going from solid to gas? Is this phase change endothermic or exothermic?
Sublimation (solid to gas)
Endothermic (gas particles have more energy than solid which means energy was gained)
400
During a phase change, why doesn't the temperature change?
Energy is going into breaking the INTERMOLECULAR FORCES which allows the particles to space farther apart and change phases. Energy isn't going into increasing particle movement/temperature.
400
Increasing the temperature of a gas at a constant volume causes the pressure to increase. Why?
Increasing temperature causes particles to move faster which will cause the particles to collide more. More collisions means more pressure.
400
A balloon at standard pressure and 20oC is moved to a new location with a pressure of 2.2 atm while maintaining the same volume. What is the new temperature
644.60 K
400
A 1 L container of oxygen gas has a pressure of 2 atm and is at a temperature of 290 K. How many moles of gas are in the container?
0.084 moles
500
Compare shape and volume between the 3 phases. (HINT: We used specific words when describing them in class)
Solid: definite shape and definite volume
Liquid: indefinite shape and definite volume
Gas: indefinite shape and indefinite volume
500
What phases are present for lines CD? for lines DE?
CD: liquid
DE: liquid and gas
500
If the amount of gas increases inside of a fixed container at a constant temperature, what will happen to the pressure? Explain what is happening to the particles inside the container.
The pressure will increase.
Increasing the amount of gas will cause more collisions between the particles. The particles aren't moving faster, however there are more particles moving in the same amount of space. More collisions means more pressure.
500
A sample of a gas occupies 10 L at 270 K and 2.1 atm. If it is heated to 340 K and expands to 33 L, what is the pressure of the gas?
0.80 atm
500
A 30g sample of oxygen gas are present at 2 atm and 24oC. What volume does the oxygen gas occupy?
11.46 L