8. a volume of 7.5 l of hydrogen gas at stp was produced from the single-replacement
reaction of zinc with nitric acid. calculate the mass of zinc needed for this reaction.

20.60 g

We are given;

Required to determine the mass of zinc needed for the reaction.

Zn(s) + 2HNO₃(aq) → Zn(NOₐ)₂ + H₂(g)

we know that 1 mole of a gas occupies 22.4 L at STP

Moles of Hydrogen = 7.05 L ÷ 22.4 L/mol

                                 = 0.315 moles

Then, we determine the number of moles of Zinc that reacted

Therefore,

Moles of Zinc = Moles of Hydrogen

Hence;

Mass of Zinc = 0.315 moles × 65.38 g/mol

                     = 20.60 g

Thus, the mass of zinc that reacted 20.60 g

um i think it might be a car?