Effusion is the process in which a gas escapes through a small hole. A student investigates the relationship between rate of effusion and relative molar mass of a gas using the apparatus shown in Fig. 2.1. [Figure 2.1] The following method is used: step 1 Turn the tap and remove any gas from the syringe through the side-arm tube, by pushing in the plunger. step 2 Add 50 cm³ of the gas being tested to the syringe through the side-arm tube. step 3 Remove the gas from the syringe, through the side-arm tube, by pushing in the plunger. step 4 Add 70 cm³ of the gas being tested to the syringe through the side-arm tube. step 5 Turn the tap to connect the syringe to the tube with the aluminium foil and small hole. step 6 Allow the syringe plunger to fall and start a timer when the volume of gas in the syringe reaches 60 cm³. step 7 Stop the timer when the volume of gas in the syringe reaches 10cm³. Record the time taken. step 8 Repeat steps 1 to 7 with different gases.