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A: A 21.3−g sample of dinitrogen monoxide is confined in a 5.76−L vessel. What is the pressure (in atm) at 111°C?

B: Find the density of Freon−11 (CFCl3) at 157°C and 4.65 atm.
g/L = ?

1 Answer

12 votes

Answer:

A. 2.65 atm.

B. 18.11 g/L.

Step-by-step explanation:

A. Determination of the pressure

Mass of N₂O = 21.3 g

Volume = 5.76 L

Temperature (T) = 111 °C

Pressure (P) =.?

First, we shall determine the number of mole in 21.3 g of dinitrogen monoxide, N₂O. This can be obtained as follow:

Mass of N₂O = 21.3 g

Molar mass of N₂O = (14×2) + 16

= 28 + 16

= 44 g/mol

Mole of N₂O =?

Mole = mass /Molar mass

Mole of N₂O = 21.3/44

Mole of N₂O = 0.484 mole

Next, we shall convert 111°C to Kelvin temperature. This can be obtained as follow:

T(K) = T(°C) + 273

Temperature (T) = 111 °C

Temperature (T) = 111 °C + 273

Temperature (T) = 384 K

Finally, we shall determine the pressure. This can be obtained as follow:

Number mole of N₂O = 0.484 mole

Volume = 5.76 L

Temperature (T) = 384 K

Gas constant (R) = 0.0821 atm.L/Kmol

Pressure (P) =.?

PV = nRT

P × 5.76 = 0.484 × 0.0821 × 384

Divide both side by 5.76

P = (0.484 × 0.0821 × 384) / 5.76

P = 2.65 atm

B. Determination of the density of CFCl₃

Temperature (T) = 157°C

Pressure (P) = 4.65 atm.

Density of CFCl₃ =?

First, we shall determine the molar mass of CFCl₃. This can be obtained as follow:

Molar mass of CFCl₃ = 12 + 19 + (35.5×3)

= 12 + 19 + 106.5

= 137.5 g/mol

Next, we shall convert 157°C to Kelvin temperature. This can be obtained as follow:

T(K) = T(°C) + 273

Temperature (T) = 157 °C

Temperature (T) = 157 °C + 273

Temperature (T) = 430 K

Finally, we shall determine the density of CFCl₃. This can be obtained as follow:

Temperature (T) = 430 K

Pressure (P) = 4.65 atm.

Molar mass of CFCl₃ (M) = 137.5 g/mol

Gas constant (R) = 0.0821 atm.L/Kmol

Density (D) of CFCl₃ =?

D = PM / RT

D = (4.65 × 137.5) / (0.0821 × 430)

D = 18.11 g/L

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