Question 5
HA student reacted magnesium with excess dilute hydrochloric acid in an open flask standing on a balance. Figure shows how the reading on the balance changed with time.
Figure: A graph of the balance reading against time for the reaction of magnesium with excess dilute hydrochloric acid
a.[2]
Explain why the balance reading falls during the first 120 seconds.
b.[1]
Explain why the balance reading stops falling after about 120 seconds.
c.[1]
Determine the mass of hydrogen that escaped from the flask.
3.1 Chemical measurements, conservation of mass and the quantitative interpretation of chemical equations Questions
40 exam-style questions on AQA GCSE Chemistry 3.1 Chemical measurements, conservation of mass and the quantitative interpretation of chemical equations, covering 3.1.1 Conservation of mass and balanced chemical equations, 3.1.2 Relative formula mass, 3.1.3 Mass changes when a reactant or product is a gas, and 3.1.4 Chemical measurements. Each one has a worked solution and a mark scheme showing where the marks go.