plzzz can you solve it quickly

thank you

1/ The reaction of methane and water is one way to prepare hydrogen.

CH4+H2O->CO2+H2

If you begin with 995g CH4 and 2510g of water what is maximum theoretical yield of H2?

2/ When the volume of 900g of ethylene at 25 C is decreased from 40 L to 25 L, what is the new temperature (in k) assuming the pressure is held constant?

3/ A level of 30 microgram Pb per deciliter of blood poses a significant health risk. Express this level as the number of Pb atoms per mL blood?