Physics Answers

80.0 cm3 of hydrogen is collected during a chemistry experiment at 20.0°C and 101 kPa.

What is its volume at IUPAC stp

A steel thick-walled gas cylinder used for storing compressed air is fitted with a safety

valve which triggers at a pressure of 1.0 x 106 Pa. The cylinder contains air at 17°C and

0.8x106 Pa. At what temperature will the safety valve trigger?

2. The density of hydrogen gas at 0°C and IUPAC standard pressure (100 kPa) is 9.00 g/m3.

a) If 1g of hydrogen gas is heated to 200°C in frictionless cylinder, find the volume it

occupies.

b) State what effect friction would have on your answer to (a).

A glass U-tube of uniform cross-sectional area is sealed at one end.

The air in the tube is initially at IUPAC standard atmospheric

pressure (100 kPa) when water is poured into the tube sealing the

U-tube and compressing the gas trapped in the sealed end.

a) If the difference in the water levels between the two sides of

the tube is x = 50.0 cm, what is the pressure of the air in the

sealed end of the tube. The density of water is 1000 kgm-3.

b) If the length of the air in the sealed end of the tube is 20.0 cm,

what pressure would be required to reduce this to 5.00 cm?

What would the value of x be to apply this pressure?

The cylinder of a pump has a volume of 25.0 cm3. It is connected to a container of

volume 225 cm3, containing air at atmospheric pressure (100 kPa). The pump draws air

from the atmospheric and pumps it into the container. Assume that the pump stroke is

slow and therefore the temperature of the air in the container remains constant.

Calculate the pressure of the air in the flask after one stroke of the pump adds more air.

A mass of gas occupies 200 cm3 at a temperature of 27.0°C and a pressure of 100 kPa.

Calculate the volume when:

a) The pressure is doubled at constant temperature

b) The absolute temperature is doubled at constant pressure

c) The pressure is increased to 150 kPa and the temperature is 127°C.

A container holds gas at 0.00°C. To what temperature must it be heated for its pressure

to double, assuming that the container does not expand?

A 2m3 volume of gas at 27.0°C is (a) heated to 327°C then (b) cooled to -123°C, both

while the pressure is constant. What are the volumes of the gas in (a) and (b)?

A glass volumetric flask holds exactly 250.00mℓ at 20.0◦C. (a) What volume would the flask hold at 50.0◦C? (b) Suppose the flask is filled with water at 50.0◦C. If the volume of the water had been 250.00mℓ at 20.0◦C, what volume would the water have at 50.0◦C? (c) Suppose instead that the flask is empty (which really means that it’s full of air). If the air inside is heated from 20.0◦C to 50.0◦C, what would the new volume of the air be?

A 15.00cm long bimetal strip is aluminum on one side and copper on the other. If the two metals are the same length at 20.0◦C, how long will each be at 800.◦C?