Sandy is conducting an investigation to find out which food his dog likes best. Which is the dependent variable
in his investigation?
A. color of dog’s dish
B. amount eaten
C. type of food given

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?