# Standard temperature and pressure problems?

1.Oxygen gas is held in a 1.00 L tank at a pressure of 12.5 atm. The gas is then released into 4.00 L tank . at a constant temperature, what is the final pressure in the system?

2.The air in a soda bottle has a pressure of 4.25 atm at sea level and a temperature of 25 celsius .

What will be the pressure of it if it's brought to a higher altitude where temperature is just 18 celsius?

3.Carbon monoxide is a product of incomplete combustion of fuels . Calculate the volume that 1.19 moles of CO gas occupies for STP

4.What is the temperature required for 0.025 moles of gas to fill a balloon to 0.51 L under 0.873 atm of pressure?

5.How many moles of helium gas will occupy an 8.1 tank at STP?

Pls explain how to do these and BA will be awarded .. i have finals next week

Update:

Any help would be greatly appreciated

Relevance

okay, so for the first two it is just simple gas laws.

1) boyles law, P1V1 = P2V2. Just plug in the values and it should work.

2) Gay-lussac's law, P1/T1 = P2/T2. Same plugging in values.

Question 3, 4 and 5 use the formula "PV = nRt" also known as the ideal gas law.

P is pressure

V is volume

n is moles

R is a constant which is 8.314 most of the time.

T is temperature in kelvin,

REMEMBER to always change temperature to kelvin (add 273.15 to the Celsius temperature)

Please like for BA, Thanks :)

• You seem to have two categories of questions. First, at STP, one mole of an ideal gas will occupy 22.4 liters.

The others can use the combined gas laws: V1P1/T1 = V2P2/T2 where T of course is in Kelvin.

For instance, for #1, your temperature is constant, so T1 and T2 can be eliminated.