A gas has a pressure of 0.40 atm at 55.0 °C. What is the pressure at standard temperature?
please show the formula and which law is it?! thanks!!

Respuesta :

0.33 atm.

Explanation

By the Ideal Gas Law:

[tex]P \cdot V = n \cdot R\cdot T[/tex]

Where

  • [tex]P[/tex] is the pressure of this gas,
  • [tex]V[/tex] is the volume of the ideal gas,
  • [tex]T[/tex] is the temperature of the gas in degrees Kelvins.
  • [tex]n[/tex] is the number of moles of gas particles in this gas, and
  • [tex]R[/tex] is the ideal gas constant.

[tex]T_1 =55.0 \; \textdegree\text{C} = (55.0 + 273.15) = 328.15 \; \text{K}[/tex].

[tex]T_2 = 0 \; \textdegree\text{C} = 273.15 \; \text{K}[/tex] under STP standard conditions.

[tex]P_1 = \dfrac{n \cdot R\cdot T_1}{V}[/tex],

[tex]P_2 = \dfrac{n \cdot R\cdot T_2}{V}[/tex].

The value of [tex]n[/tex], [tex]R[/tex], and [tex]V[/tex] shall be the same in the two equations.

Divide the second equation with the first:

[tex]\dfrac{P_2}{P_1} = \dfrac{n\cdot R\cdot \dfrac{1}{V}}{n\cdot R\cdot \dfrac{1}{V}} \cdot \dfrac{T_2}{T_1} = \dfrac{T_2}{T_1}[/tex].

[tex]P_2 = P_1 \cdot \dfrac{T_2}{T_1} = 0.40 \times \dfrac{273.15}{328.15} = 0.33 \; \text{atm}[/tex].

znk

Answer:

Gay-Lussac's Law; p₁/T₁ = p₂/T₂; 0.33 atm

Step-by-step explanation:

The volume and number of moles are constant, so we can use Gay-Lussac’s Law:

At constant volume, the pressure exerted by a gas is directly proportional to its temperature.

p₁/T₁ = p₂/T₂     Invert each side of the equation

T₁/p₁ = T₂/p₂     Multiply each side by p₂

   T₂ = T₁ × p₁/p₂

    p₂ = p₁ × T₂/T₁

Data:

p₁ = 0.40 atm; T₁  = 55.0 °C

p₂ = ?;              T₂ =   0.0 °C

Calculations:

(a) Convert the temperatures to kelvins

T₁ = 55.0 + 273.15 = 328.15 K

T₂ =   0.0 + 273.15 = 273.15 K

(b) Calculate the new pressure

p₂ = 0.40 × 273.15/328.15

    = 0.40 × 0.832

    = 0.33 atm

The pressure drops to 0.33 atm.

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