8.4: Unit 8 Practice Problems

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Question 1.

If the pressure inside a tank is 100. psi, what is this pressure in kPa, mPa, atm, mmHg?

Answer: \[\mathrm{100\: \cancel{psi.} \times \dfrac{101\: kPa}{14.7\:\cancel{psi.}}=687\: kPa}\] \[\mathrm{100\: \cancel{psi.} \times \dfrac{0.101\: MPa}{14.7\:\cancel{psi.}}=0.687\: MPa}\] \[\mathrm{100\: \cancel{psi.} \times \dfrac{1\: atm}{14.7\:\cancel{psi.}}=6.8\: atm}\] \[\mathrm{100\: \cancel{psi.} \times \dfrac{760\: mmHg}{14.7\:\cancel{psi.}}=5170\: mmHg}\]

Question 2.

A gas occupies a volume of 17.4L at 11.2 psi, what will it's volume be if the pressure is increased to 13.6psi and the temperature is held constant?

Answer: P₁V₁ = P₂V₂ (11.2psi)(17.4L) = (13.6psi)(V₂ ) V₂ = 14.3L

Question 3.

A gas has a volume of 186mL at 32°C, what will it's volume be if the temperature of the gas is increased to 104°C and the pressure is held constant?

Answer: V₁/T₁ = V₂/T₂ Remember that when using gas laws, temperature should always be in K. (186mL) / (305K) = (V₂) / (377K) V₂= 230mL

Question 4.

A container of neon at a pressure of 550mmHg and a temp of 120°C is heated (at a constant volume) until the temperature is 360°C. What is the new pressure of the heated neon?

Answer: P₁/T₁ = P₂/T₂ Remember that when using gas laws, temperature should always be in K. (550mmHg) / (393K) = (P₂) / (633K) P₂= 890 mmHg

Question 5.

A cylinder containing 12.0L of compressed air at 23.0atm and -20.0°C is opened and the air escapes into a room which has a pressure of 0.960atm and warms to 28.0°C, what is the final volume of the air from the cylinder?