What is the pressure inside a tank when it contains 87.3 moles of helium if it holds 52.0 miles at 9.63 atm

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?

Cryolite, na3alf6(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. start this question by first balance the chemical equation.1.) balance the equation: - alo3(s)+naoh(l)+hf(> na3alf6+h2o(g). 2.) if 17.5 kilograms of al2o3(s), 51.4 kilograms of naoh(l), and 51.4 kilograms of hf(g) react completely, how many kilograms of cryolite will be produced? 3.)which reactants will be in excess, (al2o3, naoh, or hf) 4.)what is the total mass of the excess reactants left over after the reaction is complete in kg?

What is the work done by the electric force to move a 1 c charge from a to b?