If i measure the pressure after the change to be 20 atm

Question

1. A gas that has a volume of 28 liters, a temperature of 45 0C, and an unknown pressure has its volume increased to 34 liters and its temperature decreased to 35 0C.  If I measure the pressure after the change to be 2.0 atm, what was the original pressure of the gas?
2. If I have an unknown quantity of gas at a pressure of 1.2 atm, a volume of 31 liters, and a temperature of 87 0C, how many moles of gas do I have?
3. A soda bottle is flexible enough that the volume of the bottle can change even without opening it.  If you have an empty soda bottle (volume of 2 L) at room temperature (25 0C), what will the new volume be if you put it in your freezer (-4 0C)?
4. If I have 17 liters of gas at a temperature of 67 0C and a pressure of 88.89 atm, what will be the pressure of the gas if I raise the temperature to 94 0C and decrease the volume to 12 liters?
5. A tire has a pressure of 2.0 atm and 30 degrees Celsius.  At the end of a long trip, the tire pressure increased to 2.5 atm.  What is the new temperature inside of the tire in degrees Celsius?
6. A sample of oxygen gas is under a 2.00 atm pressure, in a 10 L container, at 100 degrees Celsius.  How many grams of oxygen are there in this sample?