Self assessment
Question 1 of 4
The following data has been produced by drawing tangents to a curve for the hydrogen evolved in a chemical reaction. Which of the following examples shows the highest rate of reaction for the reaction between magnesium ribbon and hydrochloric acid?
A
5 cm3 of hydrogen in 10 s.
B
25 cm3 in 15 s.
C
10 cm3 in 10 s.
D
12 cm3 in 7.2 s.
What method might be the most reliable for determining the rate of reaction between 2 g of zinc carbonate and bench concentration hydrochloric acid?
A
Gas syringe.
B
Collection of gas under water.
C
Measuring mass loss.
Sodium thiosulfate reacts with acid precipitating sulfur. This makes the contents of the reaction vessel become turbid. The rate of reaction is often measured by observing a black cross on a piece of paper through the reaction mixture. What does the disapperance of the black cross indicate?
A
The end of the reaction.
B
That a set amount of sulfur has been created.
C
That the reaction is slowing down.
Look at the graph.
[INSERT MEA_SA_01_ima]
Two tangents have been drawn to the curve in order to determine the rate of reaction. Which of the following statements is the best description of the rate being measured?
A
Triangle A represents the initial rate of reaction, which is 30 cm3 of gas produced in 7 s.
B
Triangle B represents the rate of reaction at 25 s, which is less than the initial rate and is 15 cm3 of gas produced in 29 s.
C
From triangle A we can calculate that the initial rate of the reaction is measured by the volume of CO2 gas produced and is 4.3 cm3 s–1.
D
The rate of reaction at B is 5.2 cm3 s-1 whilst the rate at A is 4.2 cm3 s-1