What is a main difference between a mixture and a pure substance? a A mixture is only a liquid, but a pure substance can be in any state. b A mixture can vary in composition, but a pure substance has a set composition. c A mixture can be made up of a single compound, but a pure substance cannot. d A mixture looks the same throughout, but a pure substance does not.

Answerthe energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.explanationwe define electric potential as the ratio electric potential energy to the charge,    then the following gives us the potential difference,      the formula  may be on your formula sheet.the change in electric potential energy would be the energy that would needed to move it from point a to point b. solving for that, we get    using q = 8.00  × 10⁻¹⁹ c and  δv = 2.00 v, we get    the energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.