Question

Consider the reaction that results from the addition of 50.0 g of Zinc metal (Zn) to 60.0 g of hydrochloric acid (HCl)? Generate a balanced equation for this reaction and then answer the folling (3) questions.

1) What is the limiting reactant?

A) zinc

B) hydrochloric acid

C) zinc chloride

D) hydrogen gas

E) hydrogen gas

2) How much hydrogen gas forms?

A) 2.68g

B) 0.77g

C)0.83g

D) 8.35g

E) 1.55g

3) How much excess reagent is left over?

A) 4.26g

B) 22.13g

C) 11.9g

D) 9.43g

E) 4.35g

Answer 1

1) reaction is

Zn + 2HCl    ZnCl₂  + H₂

molar mass of Zn = 65.38 gm/mol

molar mass of HCl = 36.46 gm/mol then 2 mole of HCl = 72. 92 gm

According to reaction 1 mole of Zn react with 2 mole of HCl that mean 65.38 gm Zn react with 72.92 gm HCl then to react with 50 gm of Zn required HCl = 50 72.92 / 65.38 = 55.76 gm but HCl given 60 gm therefore HCl is excess reagent and Zn is the limiting reagent.

Answer - A) Zink

2) molar mass of Zn = 65.38 gm/mol

molar mass of H₂ = 2.01

According to reaction 1 mole of Zn produce 1 mole of H₂ that mean 65.38 gm of Zn produce 2.01 gm of H₂ then 50 gm of Zn produce = 50 2.01/65.38 = 1.55 gm

Answer - E) 1.55 gm

3)

According to reaction 1 mole of Zn react with 2 mole of HCl that mean 65.38 gm Zn react with 72.92 gm HCl then to react with 50 gm of Zn required HCl = 50 72.92188 / 65.38 = 55.76 gm but HCl given 60 gm

Thus, 60 - 55.76 = 4.24 4.26

Answer - A) 4.26 gm