how many liters of oxygen are there if the gas is in a container at 2 atm, 20 C and there are 2 mol of O2

Iknow #2 is d. i just need to know why

Which fossil fuel is mainly used for heating and cooking? a. electricity b. coal c. petroleum d. natural gas

The equation below shows a chemical reaction. a + b + heat —> c + d according to the law of conservation of energy, which statement is true? a. the reactants absorb heat because they have less energy than the products. b. the products release heat because they have more energy than the reactants. c. the reactants generate heat because they have more energy than the products. d. the products require heat to form because they have less energy than the reactants.