Astudent needs to determine the volume occupied by a gas in a 125 ml flask using the experimental setup described in the procedure. the student measures the volume of the flask to be 159 ml to the top of the flask. the student measures the volume of the flask with a stopper in it to be 142 ml. the student performs the experiment by reacting the strip of magnesium with 5 ml of hcl solution. what is the volume of the flask occupied by the hydrogen gas?