Question

A sample of Cl2 gas occupies 8.50 L at 80 °C and 740 mmHg. What volume will the Cl2 occupy at STP? *

Answer 1

Explanation:

GIVEN

• Volume = 8.50 L
• Temperature = 80°C or 353 K
• Pressure = 740 mmHg

To find

• Volume occpied by Cl₂ at STP

Assumption

• V1 = 8.50 L
• T1 = 353 k
• T2 = 302.5 k

(P1 × V1/T1) = (P2 × V2/T2)

V1/T1 = V2/T2

V2 = (V1 × T2)/T1

V2 = (8.50 × 302.5) / 353

V2 = 7.28 L

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Answer 2

Given: Volume of Cl₂ gas, V₁ = 8.50L

            Temperature, T₁ = 80 ⁰C

            Pressure exerted by Cl₂  gas ,P1 = 740 mmHg

To Find: Volume occupied by Cl₂ gas at STP, V2.

Solution:

To calculate V₂, the formula used:

• P₁V₁ / T₁ = P₂ V₂ / T₂

        Here, P₂, is the pressure at gas at STP = 760mmHg

        T₂ is the temperature at STP = 273.15K

Applying the above formula:

740 x 8.50 / 80 = 760 x V₂ / 273.15

First convert 80⁰C into K:

80⁰C = 80 + 273.15

         = 353.15 K

Convert 8.50 L in ml:

1 L = 1000ml

8.50 L = 8.50x 1000

           = 8500 ml

Putting these values in the formula for V₂:

740 x 8500 / 353.15 = 760 x V₂ / 273.15

6290000/ 353.15 = 760 x V₂ / 273.15

1.78 x 10000 = 760 x V₂ / 273.15

1.78 X 10000 x  273.15 = 760 x V₂

17800 x 273.15 / 760 = V₂

4862070 / 760 = V₂

6397.5 = V₂

V₂ = 6397.5 ml

Hence, the volume occupied by the Cl₂ gas is 6397.5 mL.