What volume of chlorine gas, measured at STP, is required for the complete reaction with a… — JAMB UTME

What volume of chlorine gas, measured at STP, is required for the complete reaction with a given mass of iron metal?

Cevap:When

11.2\text{ g}

of iron reacts completely with excess dry chlorine gas according to the balanced equation:

2Fe(s) + 3Cl_2(g) \rightarrow 2FeCl_3(s)

the volume of chlorine gas consumed at STP is 【6.72】

\text{dm}^3

.
[Relative atomic mass:

\text{Fe} = 56

; Molar gas volume at STP

= 22.4\text{ dm}^3\text{ mol}^{-1}

]

The volume of chlorine gas consumed at STP is

6.72\text{ dm}^3

To find the volume of

Cl_2

gas consumed at STP, first determine the amount of

Fe

in moles:

\text{Moles of } Fe = \frac{11.2\text{ g}}{56\text{ g mol}^{-1}} = 0.20\text{ mol}

. From the balanced equation

2Fe(s) + 3Cl_2(g) \rightarrow 2FeCl_3(s)

2\text{ moles of } Fe

react with

3\text{ moles of } Cl_2

. Therefore,

0.20\text{ mol of } Fe

requires

0.20 \times \frac{3}{2} = 0.30\text{ mol of } Cl_2

. At STP,

1\text{ mole of gas}

occupies

22.4\text{ dm}^3

, so the volume of

Cl_2

0.30\text{ mol} \times 22.4\text{ dm}^3\text{ mol}^{-1} = 6.72\text{ dm}^3

Calculate the number of moles of iron reacted

\text{Moles of } Fe = \frac{11.2\text{ g}}{56\text{ g mol}^{-1}} = 0.20\text{ mol}

Convert the mass of iron to moles using its relative atomic mass.

Determine the moles of chlorine gas (

Cl_2

) required using the stoichiometric mole ratio

\text{Moles of } Cl_2 = 0.20\text{ mol } Fe \times \frac{3\text{ mol } Cl_2}{2\text{ mol } Fe} = 0.30\text{ mol}

The balanced chemical equation shows that

2\text{ moles of } Fe

react with

3\text{ moles of } Cl_2

2:3

mole ratio).

Calculate the volume of

Cl_2

gas consumed at STP

\text{Volume of } Cl_2 = 0.30\text{ mol} \times 22.4\text{ dm}^3\text{ mol}^{-1} = 6.72\text{ dm}^3

Multiply the number of moles of

Cl_2

by the molar volume of a gas at STP.

Mass-Volume Stoichiometric Calculations at STP

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