A gas sample containing 1.94 moles at 25°C exerts a pressure of 450. torr. Some gas is added to the same container and the temperature is increased to 40.°C. If the pressure increases to 750. torr, how many moles of gas were added to the container? Assume a constant-volume container.

Respuesta :

Answer : The number of moles of gas added to the container were, 3.078 mole

Explanation :

Using ideal gas equation,

[tex]PV=nRT[/tex]

At constant volume the formula will be,

[tex]\frac{P_1}{P_2}=\frac{n_1\times T_1}{n_2\times T_2}[/tex]

where,

[tex]n_1[/tex] = initial moles of gas = 1.94 moles

[tex]n_2[/tex] = final moles of gas = ?

[tex]P_1[/tex] = initial pressure of gas = 450 torr

[tex]P_2[/tex] = final pressure of gas = 750 torr

[tex]T_1[/tex] = initial temperature of gas = [tex]25^oC=273+25=298K[/tex]

[tex]T_2[/tex] = final temperature of gas = [tex]40^oC=273+40=313K[/tex]

Now put all the given values in the above formula, we get:

[tex]\frac{450torr}{750torr}=\frac{1.94mole\times 298K}{n_2\times 313K}[/tex]

[tex]n_2=3.078mole[/tex]

Therefore, the number of moles of gas added to the container were, 3.078 mole

Answer:

3.078 moles

Explanation:

Given:

Number of moles of gas, n = 1.94 moles

Initial temperature, T₁ = 25° C = 298 K

Initial pressure, P₁ = 450 torr

Final temperature, T₂ = 40° C = 313 K

Final pressure, P₂ = 750 torr

now,

we know

PV = nRT

where,

P is the pressure

V is the volume

n is the number of moles

R is the universal gas constant

T is the temperature

now for the initial stage, the above relation comes as:

450 × V = 1.94 × R × 298  .............(1)

for the final stage

750 × V = n × R × 313   ............... (2)

on dividing the equation 2 by 1 we get

[tex]\frac{750}{450}=\frac{n\times313}{1.94\times298}[/tex]

or

n = 3.078 moles