C2(ii) - Rates of Reaction 3.

Rates of Reaction Experiments.

Remember: Any reaction can be used to investigate any of the four factors that affect rate. This revision note illustrate four important reactions, but only one factor can be considered for each. But we can just as easily use the marble chips/acid reaction to test the effect on temperature instead. 

1) Reaction of Hydrochloric Acid (HCL) and Marble Chips.

This experiment is often used to demonstrate the effect of breaking a solid into small bits. You place marble chips in a beaker filled with dilute HCL and use a gas syringe to measure the volume of CO2 produced.

a) Measure the volume of gas evolved with a gas syringe and take readings at regular intervals.

b) Make a table of readings and plot them as a graph. You choose regular time intervals, so time is the independent variable (x) and volume is the dependent variable (y).

c) Repeat the experiment with exactly the same volume of acid, and exactly the same mass of marble chips, but with the marble more crunched up.

d) Then repeat with the same mass of powdered chalk instead of marble chips.

This Graph Shows the Effect of Using Finer Particles of Solid.

1) An increase in surface area causes more collisions, so the rate of reaction is faster.

2) If you double the mass of small chips the line on the graph becomes steeper.

3) The extra surface area gives a quicker reaction and so there's more gas evolved overall.

2) Reaction of Magnesium Metal With Dilute HCL.

This is where you place magnesium metal in a flask filled with hydrochloric acid. You place in on a mass balance and calculate the mass that is lost in hydrogen gas. At each interval you can increase the concentration of the acid.

a) This reaction is good for measuring the effects of increased concentration (as is the marble/acid reaction).

b) This reaction gives off hydrogen gas, which…