Question

Which of the following is an example of a chemical change?
-water boiling to produce a gas
-baking soda and vinegar combining to form a gas and a solid
-grinding cinnamon and sugar together
-adding hot water to freeze-dried coffee

Answer 1

baking soda and vinegar combining to form a gas. This is the only reaction where we have two reactants forming products that are different from what you started with. The key is that a solid and gas are formed whereas the others are simply either being combined with no change or there is a physical change only as in the first example.