Explanation:
substance Q could be <em><u>oxygen (O2)</u></em>
substance R could be <em><u>carbon</u></em><em><u> </u></em><em><u>d</u></em><em><u>i</u></em><em><u>o</u></em><em><u>x</u></em><em><u>i</u></em><em><u>d</u></em><em><u>e</u></em><em><u> </u></em><em><u>(</u></em><em><u>C</u></em><em><u>O</u></em><em><u>2</u></em><em><u>)</u></em>
A persons weight changes as he travels from earth to space but his mass remains the same
A solution is a homogeneous mixture of two or more substances. a solution doesn't allow light to scatter. the solute cannot be separated mechanically from the solution.
I believe that it is a chemical change.