# 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

Any help would be greatly appreciated

### 2 Answers

- 8 years agoBest Answer
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 :)

Source(s): http://en.wikipedia.org/wiki/Gas_laws - cat loverLv 78 years ago
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.