How many liters of h2 gas can be produced at 0 ? c and 1.00 atm (stp) from 42.0 g of zn? zn(s)+2hcl(aq)? zncl2(aq)+h2(g)?

The chemical reaction would be :

Zn(s)+2HCl(aq) = ZnCl2(aq)+H2(g)

At STP 1 mol of an ideal gas is equa to 22.4 L of the gas. We need to assume that H2 produced is an ideal gas. We can calculate as follows:

42.0 g Zn ( 1 mol / 65.38 g ) ( 1 mol H2 / 1 mol Zn ) ( 22.4 L / 1 mol ) = 14.39 L H2 produced