Can someone answer this question?

Calculate the mass of silver needed to react with chlorine to produce 126g if silver chloride?

How does a sample of helium at 15 degree celsius compare to a sample of helium at 215 k? a) the helium at 15 degrees celsius has a higher average kinetic energy that the sample at 215 k. b) the helium at 15 degrees celsius has lower nuclear energy that the sample at 215 k. c) the helium at 15 degrees celsius has slower- moving atoms that the sample at 215 k. d) the helium at 15 degrees celsius has smaller atoms than the sample at 215 k.

What mass of ca(oh)2 is needed to make 1250ml of a .75m solution?