Question

At T = 0 degrees C and P= 1 ATM how many grams of mg (atomic mass = 24.3 g/mol) are required to produce 400ml of H2 in the reaction shown below?

Mg (s) + 2 HCL (aq) ---> H2 (g) + mgcl 2 (aq)

Answer 1

Mg (s) + 2 HCL (aq) ---> H2 (g) + MgCl 2 (aq)

P = 1atm

T   = 0⁰C   = 0+273 = 273K

V   = 400ml = 0.4L

PV = nRT

n = PV/RT

   = 1*0.4/0.0821*273   = 0.0178moles

Mg (s) + 2 HCL (aq) ---> H2 (g) + MgCl 2 (aq)

from balanced equation

1 moles of H2 produced from 1 mole of Mg

0.0178 moles of H2 produced from 0.0178 moles of Mg

mass of Mg = no of moles * gram atomic mass

                    = 0.0178*24.3   = 0.43g of Mg >>>>>answer