# Understanding the difference between physical and chemical changes

Which of the following is a chemical change?

A. Hydrolysis of a dipeptide.

B. Stretching of a balloon.

C. Freezing of water.

D. Breaking a stick.

I'm pretty sure that the answer is (A), but I'm not 100% positive.

I know that, for (C), you can freeze water, and then you can melt it back to liquid water.

For (D), you can break a stick, and the stick is still now two sticks.

For (B), however, I think that it is a physical change, but I'm not entirely certain.

Can someone please explain this for me?

• It seems you're getting it more or less right. – Mithoron Oct 15 '16 at 22:57
• Hopefully! I'm getting graded on this! – 关一骏 Oct 15 '16 at 23:00