Balance the following Equation:

___Zn + ___HCl --> ___ZnCl2 + ___H2
50g of zinc are reacted with 50g of hydrogen chloride. Calculate the amount of excess reactant.


A- 4.2g

B- 5.1g

C- 1.4g

D- 2.3g

Respuesta :

Answer:

The amount of excess is 5.16 grams. Option B 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 n 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 remain 0.764 -0.685 = 0.079 moles

Step 5: Calculate the remaining mass of zinc

Mass = moles * molar mass

Mass Zinc = 0.079 moles *65.38 g/mol

Mass Zinc = 5.16 grams

The amount of excess is 5.16 grams. Option B is correct

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]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]

For step 5:

Calculating the mass of [tex]Zn[/tex]:

Formula:

[tex]\to \text {Mass of (Zn) = moles} \times \text{molar mass}[/tex]

                      [tex]= 0.079\ moles \times 65.38\ \frac{g}{mol}\\\\= 5.16\ grams[/tex]

Calculating the excess amount of [tex]\ \bold{5.16}\ grams[/tex].

Therefore, the final answer is "Option B".

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