What happens when the pressure of a gas is lowered? A. The number of molecules increases. B. The molecules collide less frequently. C. The molecules decrease in volume. D. The temperature of the system increases.

Which is true of the reactants in this displacement reaction? fe + 2hcl fecl2 + h2 a. the reactants are located to the left of the arrow in the chemical equation. b. the reactants contain 1 iron atom, 2 hydrogen atoms, and 1 chlorine atom. c. the reactants are the atoms, molecules, or compounds formed in the reaction. d. the reactants have the same physical and chemical properties as the products.

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 does the xylem do? stores the glucose captures the sunlight absorbs oxygen into the leaf carries water from the roots to the leaves