Topic 6 - The rate and extent of chemical change

Question 1

What is meant by equilibrium

Answer 1

A reversible reaction where the forwards and backwards reactions occur at the same rate in a closed system - so the concentrations of the products and the reactants remain constant

Question 2

describe why a graph plateus

Answer 2

At first, the line is steep as hydrogen is produced very quickly. The curve then gets less steep as hydrogen is produced more slowly, and it plateaus as no more hydrogen is produced.

This happens because at first there was a high concentration of sodium and hydrochloric acid, so the reaction could take place very quickly. As they continue to react though, their concentrations decrease, which means that rate of reaction must also decrease. After a while, there is no sodium or hydrochloric acid left so the reaction stops.