What is number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction

Agas at 155 kpa and standard temperature has an initial volume of 1.00 l. the pressure of the gas rises to 500 kpa as the temperature also rises to 135°c. what is the new volume? 2.16 l 0.463 l 0.207 l 4.82 l

In what environment would mineral formation caused by high pressures and high temperatures most likely occur?

An alloy contains 66 g of pure zinc. what is the percentage of zinc in the alloy? express your answer to two significant figures and include the appropriate units.