# physics/chemistry

posted by .

(a) An ideal gas occupies a volume of 1.0 cm3 at 20°C and atmospheric pressure. Determine the number of molecules of gas in the container.
i got that right to be 2.5e19 molecules
(b) If the pressure of the 1.0 cm3 volume is reduced to 1.0 10-11 Pa (an extremely good vacuum) while the temperature remains constant, how many moles of gas remain in the container?
im not sure how to do this part. and i keep getting it wrong. can you please help me?

• physics/chemistry -

Atmospheric pressure is 1.015*10^5 Pa

A decrease in pressure to 10^-11 Pa is a factor of 10^16 reduction.

At the same temperature, the number of moles and molecules present in the fixed volume must decrease by a factor of 10^16.

The number of moles in part A is the number of molecules divided by Avogadro's number.

## Similar Questions

1. ### Physics

(a) An ideal gas occupies a volume of 1.6-cm3 at 20°C and atmospheric pressure. Determine the number of molecules of gas in the container. (b) If the pressure of the 1.6-cm3 volume is reduced to 1.6 10-11 Pa (an extremely good vacuum) …
2. ### Chemistry

In a fixed volume container, 6*10^23 molecules of a gas exert a pressure of 12 N/m^2. If 12*10^23 molecules of gas were added to the container, what would the pressure become?
3. ### physics

A container of volume 14.2 cm3 is initially filled with air. The container is then evacuated at 0oC to a pressure of 32 mPa. How many molecules are in the container after evacuation if we assume that air is an ideal gas?
4. ### Intro to Physics

(a) An ideal gas occupies a volume of 3.0 cm3 at 20°C and atmospheric pressure. Determine the number of molecules of gas in the container. _____________molecules (b) If the pressure of the 3.0-cm3 volume is reduced to 2.4 × 10−11 …
5. ### Chemistry;HELP

1. A sample of gas under a pressure of 622 kPa has a volume of 233 cm3. The pressure is increased to 988 kPa, while the temperature remains constant. What volume will the gas occupy at this pressure?
6. ### CHEMISTRY!! D:

1. A sample of gas under a pressure of 622 kPa has a volume of 233 cm3. The pressure is increased to 988 kPa, while the temperature remains constant. What volume will the gas occupy at this pressure?
7. ### Physics

A container of volume 19.4 cm3 is initially filled with air. The container is then evacuated at 0oC to a pressure of 6.0 mPa. How many molecules are in the container after evacuation if we assume that air is an ideal gas?
8. ### chemistry

we believed that the molecules of a gas move around fairly rapidly, we can use this to explain all of the following EXCEPT why adding more gas increases the pressure. why most of the volume of the gas sample is taken up by the gas …