How to do this question plz answer me

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Chemistry worksheet - i am not sure what they are asking for exactly?

)a children’s liquid cold medicine has a density of 1.23 g/ml. if a child is to take 2.5 tsp in a dose, what is the mass in grams of this dose? (1 tsp = 5 ml)