The molar mass of nh3 is 17.03 g/mol. the molar mass of h2 is 2.0158 g/mol. in a particular reaction, 0.575 g of nh3 forms. what is the mass, in grams, of h2 that must have reacted, to the correct number of significant figures?

The balanced chemical reaction is:

N2 + 3H2 = 2NH3

We are given the amount of ammonia formed from the reaction. This is where we start our calculations.

0.575 g NH3 (1 mol NH3 / 17.03 g NH3) (3 mol H2 / 2 mol NH3) ( 2.02 g H2 / 1 mol H2) = 0.10 g H2

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2