Balance the following Equation:

___Zn + ___HCl --> ___ZnCl2 + ___H2

50g of zinc are reacted with 50g of hydrogen chloride. What is the excess reactant?
A: HCl

B: H2

C: Zn

D: ZnCl2

Respuesta :

Answer:

Zn is the excess reactant (0.079 moles in excess)

Option C is correct

Explanation:

Step 1: Data given

Mass of Zinc (Zn) = 50.0 grams

Mass of Hydrogen chloride (HCl) = 50.0 grams

atomic mass Zn = 65.38 g/mol

Molar mass HCl = 36.46 g/mol

Step 2: The balanced equation

Zn + 2HCl → ZnCl2 + H2

step 3: Calculate moles

Moles = mass / molar mass

Moles Zn = 50.0 grams / 65.38 g/mol

Moles Zn = 0.764 moles

Moles HCl = 50.0 grams / 36.46 g/mol

Moles HCl = 1.37 moles

Step 4: Calculate limiting reactant

For 1 mol Zn we need 2 moles HCl to produce 1 mol ZnCl2 and 1 mol H2

HCl is the limiting reactant. It will completely be consumed (1.37 moles)

Zn is in excess. There will react 1.37/2 = 0.685 moles

There will be 0.764 -0.685 = 0.079 moles  in excess

Following are the calculating steps for the given equation:

For step 1:

Given Data:

Mass of [tex](Zn) = 50.0\ grams[/tex]

Mass of [tex](HCl) = 50.0 \ grams[/tex]

Calculating the atomic mass [tex]Zn = 65.38\ \frac{g}{mol}[/tex]

Calculating the Molar mass [tex]HCl = 36.46 \ \frac{g}{mol}[/tex]

For step 2:

Calculating the equation balancing:

[tex]\bold{Zn + 2HCl \to ZnCl_2 + H_2}[/tex]

For step 3:

Calculating the moles:

[tex]\to Moles = \frac{mass}{molar\ mass}[/tex]

Moles of [tex]Zn= \frac{50.0\ grams}{65.38\ \frac{g}{mol}} = 0.764\ moles[/tex]

Moles of [tex]HCl = \frac{50.0\ grams}{ 36.46\ \frac{g}{mol}}= 1.37\ moles[/tex]

For step 4:

Calculating the limiting of the reactant:

  • When the [tex]1 \ mol\ Zn[/tex] we need [tex]2\ moles\ HCl[/tex] to produce [tex]{ 1\ mol\ ZnCl_2 \ and\ 1 \ mol \ H_2}[/tex] [tex]HCl[/tex] is the limiting reactant.
  • It will absolutely consume ([tex]1.37\ moles[/tex]) [tex]Zn[/tex] is in excess.
  • Calculating the react value [tex]\ \frac{1.37}{2} = 0.685\ moles\\\\[/tex]

            [tex]\to 0.764 -0.685 = 0.079\ moles[/tex]

Therefore, the final answer is "Option C".

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