Question

Can anybody check my answer?

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A given mass of air has a volume of 10.00L at 100kPa. What volume will it occupy at 50kPa if the temperature does not change?

Five moles of a gas occupies 20L of space with a pressure of 101.3kPa. What is the temperature of the gas?

Answer 1

`\boxed{\text{25. 20 L; 26. 49 K}}`

Step-by-step explanation:

25. Boyle's Law

The temperature and amount of gas are constant, so we can use Boyle’s Law.

`p_(1)V_(1) = p_(2)V_(2)`

Data:

`\begin{array}{rcrrcl}p_(1)& =& \text{100 kPa}\qquad & V_(1) &= & \text{10.00 L} \\p_(2)& =& \text{50 kPa}\qquad & V_(2) &= & ?\\\end{array}`

Calculations:

`\begin{array}{rcl}100 * 10.00 & =& 50V_(2)\\1000 & = & 50V_(2)\\V_(2) & = &\textbf{20 L}\\\end{array}\\\text{The new volume will be } \boxed{\textbf{20 L}}`

26. Ideal Gas Law

We have p, V and n, so we can use the Ideal Gas Law to calculate the volume.

pV = nRT

Data:

p = 101.3 kPa

V = 20 L

n = 5 mol

R = 8.314 kPa·L·K⁻¹mol⁻¹

Calculation:

101.3 × 20 = 5 × 8.314 × T

2026 = 41.57T

`T = (2026)/(41.57) = \textbf{49 K}\\\\\text{The Kelvin temperature is }\boxed{\textbf{49 K}}`