Zinc metal reacts with hydrochloric acid according to the balanced chemical equation: \text{Zn}_{(s)} + 2\text{HCl}_{(aq)} \rightarrow \text{ZnCl}_{2(aq)} + \text{H}_{2(g)} If 13.0\text{ g} of zinc is added to a solution containing 7.3\text{ g} of hydrochloric acid, what mass of zinc remains unreact

Zinc metal reacts with hydrochloric acid according to the balanced chemical equation: \tex… — JAMB UTME

Zinc metal reacts with hydrochloric acid according to the balanced chemical equation:

\text{Zn}_{(s)} + 2\text{HCl}_{(aq)} \rightarrow \text{ZnCl}_{2(aq)} + \text{H}_{2(g)}

13.0\text{ g}

of zinc is added to a solution containing

7.3\text{ g}

of hydrochloric acid, what mass of zinc remains unreacted after the reaction goes to completion?
(

\text{Zn} = 65.0,\text{ H} = 1.0,\text{ Cl} = 35.5

)

$6.5\text{ g}$ Cevap
B
$5.7\text{ g}$
C
$0.0\text{ g}$
D
$3.25\text{ g}$

Cevap

The mass of zinc remaining unreacted is

6.5\text{ g}

Converting the given masses into moles shows that 0.20 mol of zinc and 0.20 mol of hydrochloric acid are present. Since 1 mole of zinc requires 2 moles of hydrochloric acid, 0.20 mol of hydrochloric acid reacts with only 0.10 mol of zinc. Hydrochloric acid is completely consumed, leaving 0.10 mol (6.5 g) of zinc unreacted.

Adım Adım Çözüm

Calculate the molar masses of the reactants

Molar mass of

\text{Zn} = 65.0\text{ g/mol}

; Molar mass of

\text{HCl} = 1.0 + 35.5 = 36.5\text{ g/mol}

Molar masses are required to convert the given masses to mole quantities.

Determine the initial mole quantities of each reactant

Moles of

\text{Zn} = \frac{13.0\text{ g}}{65.0\text{ g/mol}} = 0.20\text{ mol}

; Moles of

\text{HCl} = \frac{7.3\text{ g}}{36.5\text{ g/mol}} = 0.20\text{ mol}

Chemical reactions occur according to mole ratios, not mass ratios.

Identify the limiting reactant and calculate the moles of zinc consumed

From the equation,

1\text{ mol of Zn}

reacts with

2\text{ mol of HCl}

. Thus,

0.20\text{ mol of HCl}

requires

\frac{0.20}{2} = 0.10\text{ mol of Zn}

\text{HCl}

is the limiting reactant.

The limiting reactant determines the extent of the reaction.

Calculate the unreacted moles and mass of zinc

Unreacted moles of

\text{Zn} = 0.20\text{ mol} - 0.10\text{ mol} = 0.10\text{ mol}

. Unreacted mass of

\text{Zn} = 0.10\text{ mol} \times 65.0\text{ g/mol} = 6.5\text{ g}

Subtracting consumed moles from initial moles gives the remaining amount.

Anahtar Kavram

Limiting and Excess Reactants

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Konular

Bu konudan daha fazla soru