Ammonia and gaseous hydrogen chloride combine to form ammonium chloride. nh3+hcl-> nh4cl

if 4.21 l of nh3(g) at 27 c and 1.02 atm is combined with 5.35 l of hcl(g) at 26 c and 0.998 atm what mass of nh4cl(s) will be produced? which gas is the limiting reactant? which gas is present in excess?

The balanced chemical equation would be as follows:

NH3+HCL->NH4CL

For this, we assume these gases are ideal gases so we can use the equation PV=nRT. We first calculate the number of moles of each reactants. We do as follows:

PV=nRT
1.02 (4.21) = n (0.08206)(27+273.15)
n = 0.17 mol NH3 >consumed completely and therefore the limiting reactant

PV=nRT
0.998 (5.35 L) = n (0.08206)(26+273.15) 
n = 0.22 mol HCl

what mass of NH4Cl(s) will be produced?
0.17 mol NH3 (1 mol NH4Cl / 1 mol NH3 ) = 0.17 mol NH3

which gas is the limiting reactant?
 NH3 gas

which gas is present in excess?
HCl gas

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.