A220.0-ml sample of helium gas is in a cylinder with a movable piston at 105 kpa and 275k. the piston is pushed until the sample has a volume of 95.0ml. the new temperature of the gas is 310. k. what is the new pressure of the sample?

May someone me with these science questions

Idid a lab for chemistry where we put nails in a copper (ii) chloride solution. 1. why did the reaction stop? which reactant was used up? how do you know? 2. describe what was happening to the atoms of iron and copper during the reaction. what is this type of reaction called? 3. what would happen to the ratio of copper to iron if you had placed more nails in the beaker? if you had let the reaction go for less time? 4. what is the accepted ratio of copper atoms to iron atoms in this reaction? account for differences between your experimental value and the accepted value. write the balanced equation for the reaction.

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