A chemist hypothesizes that mercury oxide (#HgO#) will undergo a decomposition reaction reaches a temperature. When the chemist designs his experiment what should be the only independent variable?

1 Answer
Jan 6, 2018

The temperature


The independent variable of an experiment is the thing you change.

In this case, what we are changing will be the temperature.
This will allow us to find the temperature where the decomposition reaction occurs.

You could well argue that we are trying to measure the temperature, so this is the dependent variable. However, in actual fact we are "measuring" whether or not there is a decomposition reaction, and working backwards from this to determine the temperature at which this occurs.

Note that:

  • The independent variable is the thing you change.
  • The dependent variable is the thing you measure
  • The control variables are the things that stay the same to ensure that there is a fair test