CaCO3 + 2 HCl →CaCl2 + H2O + CO2
3.0 g of calcium carbonate was added to 100 cm3 of hydrochloric acid. Calculate the concentration
of HCl used.

How do you determine the percent yield of a chemical reaction

To prevent the presence of air, noble gases are placed over highly reactive chemicals to act as inert "blanketing" gases. a chemical engineer places a mixture of noble gases consisting of 4.37 g of he, 13.36 g of ne, and 36.65 g of kr in a piston-cylinder assembly at stp. calculate the partial pressure in torr of kr.

Can anyone answer these questions? ? i need it before 1: 00pm today