Question

Students in a chemistry class added 5 g of Zinc (Zn) to 50 g of hydrochloric acid (HCl). A chemical reaction occurred that produced zinc chloride (ZnCl2) and 6 g of hydrogen gas (H2).

Zn+ 2HCl → ZnCl2+H2

What is the mass of the zinc chloride?

Answer 1

The answer is 11
First you need to find the limiting reactant
n (Zn) = m/MM = 5/65.38 = 0.076 ≈ 0.08
ratio = moles/coefficient = 0.08/1 = 0.08

n(HCl) = m/MM = 50/36.45 = 1.37
ratio = moles/coefficient = 1.37/2 = 0.685

So the limiting reaction is Zn

0.08/1 = x/1
x= 0.08 moles of ZnCl2

Then u need to find the mass
m= n(MM) = 0.08 (136.28) = 10.9 ≈11

Answer 2

Answer: 11 g

Explanation:

Zn + 2HCl → ZnCl₂ + H₂

Number of moles of Zn:

Number of moles = 5 g / 65.38 g/mol

Number of moles = 0.08 mol

Number of moles of HCl :

Number of moles = 50 g / 36.5 g/mol

Number of moles = 1.4 mol

Compare the moles of both reactant with zinc chloride:

Zn : ZnCl₂

1 : 1

0.08 : 0.08

HCl : ZnCl₂

2 : 1

1.4 : 1/2×1.4 =0.7 mol

The number of moles of zinc chloride produced by Zn are less so it will limit reactants.

Mass of zinc chloride:

Mass = 0.08 mol × 136.3 g/mol

Mass = 11 g