The following statements pertain to the development of the theory of combustion by the French chemist Lavoisier in theeighteenth century. Match the statement with the appropriate step (observation, hypothesis, experiment designed to testhypothesis) in the scientific method. (a) A metal is burned in a closed container and the change in mass of the solid and volume of the gas is measured. (b) Oxygen gas combines with a substance during its combustion. (c) Combustion of a metal in a closed container ceases after a length of time.

a) Experiment designed to test hypothesis;

b) Hypothesis;

c) Observation.

Explanation:

The scientific method is a list of procedures a scientist does to explain a phenomenon. The principal steps are:

1) Observation - In this step, the matter or the phenomenon is observed;

2) Problem elaboration - In this step, some questions about the phenomenon are made;

3) Hypothesis - The questions are answered, trying to explain the phenomenon;

4) Experimentation - The hypothesis is tested with experiments and the results are analyzed to determine if the hypothesis is or not correct.

Thus, first, it was observed that the combustion of a metal in a closed container ceases after a length of time (c); then the hypothesis made was that oxygen gas combines with a substance during its combustion (b); so the experiment is done: a metal is burned in a closed container and the change in mass of the solid and volume of the gas is measured (a).