If there are 0.20 moles of CO2, how many CO2 molecules are there?

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.

What is a number added in front of a formula in order to balance the equation

Which statement best describes the liquid state of matter? a. it has definite shape but indefinite volume. b. it has definite shape and definite volume. c. it has indefinite shape and indefinite volume. d. it has indefinite shape but definite volume.