Using a gas syringe

Question 1

when can gas syringes be used

Answer 1

for a variety of experiments where the volume of a gas is measured , possibly to work out moles of gas or to follow reaction rates

Question 2

what does the volume of a gas depend on

Answer 2

the pressure and temperature so when recording volume it is important to note down the temperature and pressure of the room

Question 3

what are potential errors in using a gas syringe

Answer 3

• gas escapes before bung inserted
• syringe sticks
• some gases like carbon dioxide or sulphur dioxide are soluble in water so the true amount of gas is not measured

Question 4

what’s the method for using a gas syringe to calculate the Mr of propanone

Answer 4

1) extract 0.2cm3 of propanone into a hypodermic syringe and then measure the mass of this syringe
2) using hand protection , remove a gas syringe from the oven and note the volume of air already in the barrel - about 5cm3
3) inject the propanone through the self seal cap into the barrel. The plunger will move straight away .
4) put the gas syringe back into the oven
5) measure the mass of the empty hypodermic syringe immediately
6) after a few minutes measure the volume of the gas in the gas syringe , record the temperature of the oven shelf and the pressure of the room