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katen-ka-za [31]

3 years ago

9

10 kg of R-134a fill a 1.115-m^3 rigid container at an initial temperature of -30∘C. The container is then heated until the pres

sure is 200 kPa. Determine the final temperature an the initial pressure. Answers: 14.2∘C, 84.43 kPa

1 answer:

Sidana [21]3 years ago

4 0

Answer : The final temperature an the initial pressure of gas is, 273.6 K and 177.6 kPa

Explanation :

First we have to calculate the initial pressure of gas.

As we know that, R-134a is 1,1,1,2-Tetrafluoroethane.

Using ideal gas equation:

$PV=nRT\\\\PV=\frac{w}{M}RT$

where,

P = pressure of gas = ?

V = volume of gas = $1.115m^3$

T = temperature of gas = $-30^oC=273+(-30)=243K$

R = gas constant = $8.314m^3Pa/mole.K$

w = mass of gas = 10 kg = 10000 g

M = molar mass of R-134a gas = 102.03 g/mole

Now put all the given values in the ideal gas equation, we get:

$P\times 1.115m^3=\frac{10000g}{102.03g/mole}\times (8.314m^3Pa/mole.K)\times (243K)$

$P=177587.9687Pa=177.6kPa$

Thus, the initial pressure of gas is, 177.6 kPa

Now we have to calculate the final temperature of gas.

Gay-Lussac's Law : It is defined as the pressure of the gas is directly proportional to the temperature of the gas at constant volume and number of moles.

$P\propto T$

or,

$\frac{P_1}{T_1}=\frac{P_2}{T_2}$

where,

$P_1$ = initial pressure of gas = 177.6 kPa

$P_2$ = final pressure of gas = 200 kPa

$T_1$ = initial temperature of gas = $-30^oC=273+(-30)=243K$

$T_2$ = final temperature of gas = ?

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

$\frac{177.6kPa}{243K}=\frac{200kPa}{T_2}$

$T_2=273.6K$

Thus, the final temperature an the initial pressure of gas is, 273.6 K and 177.6 kPa

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2 years ago

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$t$ is the time for which the ball is in the air.
$v_0$ is the initial vertical velocity of the ball.

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$\begin{aligned}\text{Rolling Velocity}&=\text{Horizontal Velocity} \\&= \text{Average Horizontal Velocity}\\ &=\frac{\Delta x}{\Delta t}=\frac{0.352\;\text{m}}{0.440315\;\text{s}}=0.0799\;\text{m}\cdot\text{s}^{-1}\end{aligned}$ .

Both values from the question come with 3 significant figures. Keep more significant figures than that during the calculation and round the final result to the same number of significant figures.

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3 years ago