Question

5.00 g zinc added to hudroclric acid what is the mass of hydrogen gas

Answer 1

0.15g

Step-by-step explanation:

Given parameters:

Mass of Zn = 5g

Unknown:

Mass of hydrogen gas = ?

Solution:

To solve this problem, we must first write the reaction expression;

Zn + 2HCl → ZnCl₂ + H₂

Now find the number of moles of the known specie which is Zn;

Number of moles of Zn =
`(mass)/(molar mass)`

Molar mass of Zn = 65.4g/mol

Number of moles of Zn =
`(5)/(65.4)` = 0.08mole

1 mole of Zn will produce 1 mole of H₂

0.08 mole of Zn will give 0.08 mole of H₂

Mass of H₂ = number of moles x molar mass

molar mass of H₂ = 2(1) = 2g/mol

Mass of H₂ = 0.08mol x 2g/mol = 0.15g