765 Mmhg To Atm

Question: Example 11.1—A High-Performance Bicycle Tire Has a Pressure of 125 psi. What Is the Pressure in mmHg?
Answer: Conversion Factors Used:

1 atm = 14.7 psi
1 atm = 760 mmHg

Answer: Not Given in Presentation

My Best Guess:

125 psi = 8.5 atm

(8.5 atm)(760 mmHg/1 atm) = 6,460 mmHg

(Ch. 11 ppt, Slide 18)
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Question: Convert 836 mmHg to atm.
Answer: Conversion Factor: 1 atm = 760 mmHg

Answer: 1.10 atm

(Homework 8, #1)
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Question: Convert 0.311 atm to millimeters of mercury (mmHg).
Answer: Conversion Factor: 1 atm = 760 mm Hg

Answer: 236 mmHg
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Question: Convert 45.5 psi into kPa.
Answer: Conversion Factors Used:

1 atm = 14.7 psi
101.325 atm = 1 kPa

Answer: 313 kPa

(Ch. 11 ppt, Slide 19)
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Question: Convert 125 psi to millimeters of mercury (mmHg).
Answer: ** Pressure units must be atm! Temp. must be in Kelvin!

Conversion Factors Used:
1) 1 atm = 14.7 psi
2) 1 atm = 760 mmHg

Answer: 6.46 x 10³ mmHg
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Question: Convert 18.0 atm to Torr.
Answer: Conversion Factor: 760 Torr = 1 atm

Answer: 13,700 Torr

(Homework 8, #1)
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Question: Convert 760 Torr to Millimeters of Mercury (mmHg).
Answer: Conversion Factor: 1 mmHg = 1 Torr

Answer: 760 mmHg

(Homework 8, #1)
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Question: Convert 836 Tor to atm.
Answer: Conversion Factor: 1 atm = 760 Torr

Answer: 1.10 Torr

(Homework 8, #1)
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Question: A cylinder equipped with a moveable piston has an applied pressure of 4.0 atm and a volume of 6.0 L. What is the volume of the cylinder if the applied pressure is decreased to 1.0 atm?

Given: Pressure and Volume
Find: Final Volume (L)
Answer: Boyle's Law: P₁V₁ = P₂V₂

Answer: 24 L

(p. 369)

*Pressure must be in atm!
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Question: Calculate the pressure of a gas that was initially at 765 mmHg and 1.78 L and later compressed to 1.25 L.

Given: Pressure and Volume
Fnd: Final Pressure (atm)
Answer: Boyle's Law→ P₁V₁ = P₂V₂

Answer: 1.09 x 10³ mmHg

(p. 369)

* P must be atm!
*Temp must be Kelvin
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Question: IF we have a 2.37 L sample of a gas at 298 K that is then heated to 354 K with no change in pressure. Determine the final volume of the product.

Given: Volume and Temperature
Find: Final Volume (L)
Answer: Charles's Law → V₁/T₁ = V₂/T₂

Answer: 2.82 L

(p. 373)

* Temp. must be in Kelvin
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Question: A sample of gas has a volume of 2.80 L at an unknown temperature. When the sample is submerged in ice water at 0 degrees Celsius (273 K), its volume decreased to 2.57 L. Assume a constant pressure. Find the initial temperature in BOTH kelvin and degrees Celsius.

Given: Volume and Temperature
Find: Initial Temperature (K)
Answer: Charles's Law: (V₁/T₁) = (V₂/T₂)

Answer: 297 K and 24 degrees Celsius

(p. 374)

* Temp. must be in Kelvin
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Question: If you have a cylinder with a movable piston that has an initial volume of 3.65 L up a mountain. The pressure at the bottom of the mountain is 755 mmHg, and the temperature is 302 K. The pressure at the top of the mountain is 687 mmHg, and the temperature is 291 K. What is the volume of the cylinder at the top of the mountain?

Given: Volume, Pressure, and Temperature
Find: Volume (L)
Answer: Ideal Gas Law: (P₁V₁)/T₁ = (P₂V₂)/T₂

Answer: 3.87 L

* P must be atm!
*Temp must be Kelvin

(p. 375)
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Question: A sample of gas has an initial volume of 158 mL at a pressure of 735 mmHg and a temperature of 34 degrees Celsius. If the gas is compressed to a volume of 108 mL and heated to a temperature of 85 degrees Celsius, what is its final pressure in millimeters of mercury?

Given: Volume, Temp., and Volume
Find: Final Pressure in mmHg
Answer: Combined Gas Law: (P₁V₁/T₁) = (P₂V₂/T₂)

Answer: 1.25 x 10³ mmHg

(p. 376)

*Pressure must be in atm!!
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Question: A 4.8 L sample of helium gas contains 0.22 mol of helium. How many additional moles of helium gas must be added to the sample to obtain a volume of 6.4 L? Assume constant temperature and pressure.

Given: Moles and Volume
Find: Final # Moles (n)
Answer: Avogadro's Law = (V₁/n₁) = (V₂/n₂)

Answer: 0.07 mol

*Remember, you already have 0.29 moles, this will give you the total amount of moles needed to achieve a volume of 6.4 L.

(p. 378)
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Question: What is the pressure of 0.18 mol of a gas in a 1.2 L flask at 298 K?

Given: Moles and Temperature (K)
Find: Pressure (atm)
Answer: Ideal Gas Law: PV = nRT

Answer = 3.7 atm

*R = 0.0821 = A Constant of Proportion

(p. 381)
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Question: Calculate the volume occupied by 0.845 mol of nitrogen gas at a pressure of 1.37 atm and a temperature of 315 K.

Given: Moles, Volume, and Temperature
Find: Volume
Answer: Ideal Gas Law: PV = nRT

Answer: 16.0 L

(p. 381)

*R = 0.0821 = Constant of Proportion
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Question: Calculate the number of moles of gas in a basketball inflated to a total pressure of 24.2 psi with a volume of 3.2 L and a temperature of 25 degrees Celsius.

Given (Temp., Pressure, and Volume)
Find: Moles
Answer: Ideal Gas Law: PV = nRT

Answer 0.22 mol

*Pressure must be in atm!
*Temp. must be in Kelvin!
*R = 0.0821 = Constant of Proportion

(p. 383)
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Question: A sample of gas has a mass of 0.136 g. It's volume is 0.112 L at a temperature of 298 K and a pressure of 1.06 atm. Find its molar mass.
Answer: Use Ideal Gas Law: PV = nRT

Answer: 28.0 g/mol

*Find moles, then use mass for the answer→g/mol
*R = 0.0821 = Constant of Proportion
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Question: A sample of an ideal gas at 1.00 atm and a volume of 1.95 L was placed in a weighted balloon and dropped into the ocean. As the sample descended, the water pressure compressed the balloon and reduced its volume. When the pressure had increased to 20.0 atm, what was the volume of the sample?

*Assume that the temperature was held constant.

Given: Pressure and Volume
Find: Final Volume (L)
Answer: Boyle's Law: P₁V₁ = P₂V₂

Answer: 0.0975 L

(Homework 8, #2)
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Question: An ideal gas is allowed to expand from 4.40 L to 41.8 L at constant temperature.

1) By what factor does the volume increase?
2) This will cause the pressure to increase or decrease?
3) If the initial pressure was 141 atm, what will the final pressure be?

Given: Volume, Temperature, and Pressure
Find: Final Pressure
Answer: Ideal Gas Law: PV = nRT

Answer:
1) 9.5
2) Decrease
3) 14.842 atm

**Teacher's method has us divide the initial volume by the factor of 9.5 to get the answer.

(Homework 8, #3)
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Question: A Cylinder with a Movable Piston Has a Volume of 6.0 L at 4.0 atm. What Is the Volume at 1.0 atm?

Given: Volume and Pressure
Find: Final volume (L) after decrease (should increase)
Answer: Boyle's Law: P₁V₁ = P₂V₂

Answer: Not Given in Presentation

My Best Guess:

(6.0 L)(4.0 atm) = (V₂)(1.0 atm)
(24.0 L/atm)/1.0 atm = 24.0 L

*Pressure increase, expect volume increase!

(Ch 11 ppt, Slide 23)
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Question: A Gas Has a Volume of 2.57 L at 0 °C. What is the temperature if V = 2.80 L?

Given: Temp. and Volume
Find: Final Temp after Increase in Volume (Should Decrease)
Answer: Boyle's Law: P₁V₁ = P₂V₂

Answer: 297 K or 24 degrees Celcius

**For calculations, temperature must be in Kelvin!!

(Ch. 11 ppt, Slide 36)
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Question: The temperature inside a balloon is raised from
25.0 °C to 250.0 °C. If the volume of cold air was 10.0L, What is the volume of hot air?

Given: Temperature and Volume
Find: Final volume after temperature increase (volume should also increase)
Answer: Boyle's Law: P₁V₁ = P₂V₂

Answer: 17.5 L

(Ch. 11, Slide 38)
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Question: A Sample of Gas Has an initial volume of 158 mL at a pressure of 735 mmHg and a temperature of 34 °C. If the gas Is compressed to 108 mL and heated to 85 °C, What is the final pressure?

Given: Volume, Temperature, and Pressure
Find: Final Pressure (atm)
Answer: Combined Gas Law: P₁V₁/T₁ = P₂V₂/T₂

Answer: 1.25 x 10³ mmHg

(Ch. 11, Slide 41)
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Question: A gas occupies 10.0 L when its pressure Is 3.00 atm and temperature is 27 °C. What volume will the gas occupy under standard conditions?

Given: Volume, Pressure, and Temperature
Find: Volume under standard conditions
Answer: Use Combined Gas Law: P₁V₁/T₁ = P₂V₂/T₂

Answer: 27.3 L

*Standard Conditions: 1.00 atm, 273 K or 0 degrees Celsius
*P must be atm, Temp. must be Kelvin

STILL HAVE TO SOLVE THIS ONE!!!
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Question: A sample of gas has a mass of 0.311 g. Its volume is 0.225 L at a temperature of 55 degrees Celsius and a pressure of 886 mmHG. Find its molar mass.

Given: mass, volume, temp. and pressure
Find: molar mass
Answer: Use Ideal Gas Las: PV = nRT

Answer: 31.9 g/mol

**Pressure must be in atm (760 mmHg = 1 atm)
**Temp. must be in Kelvin
**R = 0.0821 = Constant of Proportion
**This will give you moles. Use mass for answer (g/mol)
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Question: What Is the Molar Mass of a Gas if 12.0 g occupies 197 L at 380 torr and 127 °C?
Answer: Answer: 4.0 g/mol

**Pressure must be in atm (760 Torr = 1 atm)
**Temp. must be in Kelvin
**R = 0.0821 = Constant of Proportion
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Question: A sealed container holding 0.0255 L of an ideal gas at 0.995 atm and 65 degrees celsius is placed into a refrigerator and cooled to 35 degrees celsius with no change in volume. Calculate the final pressure of the gas.

*Relationship between pressure and temperature
Answer: Use Formula: P₁/T₁ = P₂/T₂

Answer: 0.907 atm

(Homework 8, # 4)
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Question: The initial temp. of an ideal gas at 2.250 atm is 62.00 degrees Celsius. What final temp. would cause the pressure to be reduced to 1.750 atm?
Answer: Use Formula: P₁V₁/T₁ = P₂V₂/T₂ → T₂ = (P₂)(T₁/P₁)

Answer: -12.44 degrees Celsius (260.55 K)

(Homework 8, #5)
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Question: An ideal gas in a sealed container has an initial volume of 2.70 L. At constant pressure, it is cooled to 19.00 degrees Celsius, where it's final volume is 1.75 L. What was the initial temperature?
Answer: Use Formula: (P₁V₁/T₁) = (P₂V₂/T₂) → T₁ = V₁T₂/V₂

*Constant Pressure = 1

Answer: 177.514 Degrees Celsius (450.514 K)

(Homework 8, #6)
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Question: A hot air balloon is filled with 1.47 x 10⁶ L of ideal gas on a cool morning (11 degrees Celsius). The air is heated to 119 degrees Celsius. What is the volume of the air in the balloon after it is heated?
Answer: Use Formula: V₁/T₁ = V₂/T₂ → V₂ = V₁T₂/T₁

Answer: 2.02 x 10⁶ K

(Homework 8, #7)
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Question: A sample of an ideal gas has a voolume of 2.37 L at 283 K and 1.09 atm. Calculate the pressure when the volume is 1.24 L and the temp. is 298 K.
Answer: Use Formula: V₁P₁/T₁ = V₂P₂/T₂ → P₂ = V₁P₁T₂/T₁V₂

Answer: 2.1937 atm

(Homework 8, #8)
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Question: A sample of an ideal gas has a volume of 3.20 L at 10.60 degrees Celsius and 1.30 atm. What is the ovlume of the gas at 20.60 degrees Celsius and 0.994 atm?
Answer: Use Formula: P₁V₁/T₁ = P₂V₂/T₂ → V₂ = T₂V₁P₁/T₁P₂

Answer: 4.333 L

(Homework 8, #9)
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Question: If 93.5 mol of an ideal gas occupies 19.5 L at 21.00 degrees Celsius, what is the pressure of the gas?
Answer: Ideal Gas Formula: PV = nRT

Answer: 115.736 atm

(Homework 8, #10)
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Question: If 63.5 moles of an ideal gas occupies 63.5 L at 315 K, what is the pressure of the gas?
Answer: Ideal Gas Law: PV = nRT

Answer: 25.8615 atm

(Homework 8, #11)
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Question: If 4.63 moles of an idea gas has a pressure of 2.48 atm and a volume of 64.11 L, what is the temp. of the sample in degrees Celsius?
Answer: Ideal Gas Formula: PV = nRT

Answer: 145.267 degrees Celcius (418.267 K)

(Homework 8, #12)
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Question: If 9.23 moles of an ideal gas has a pressure of 2.24 atm and a volume of 41.27 L, what is the temp. of the sample?
Answer: Ideal Gas Law: PV = nRT

Answer: 121.994 K

(Homework 8, #13)
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Question: If 18.5 moles of an ideal gas is at 5.81 atm at 40.30 degrees Celsius, what is the volume of the gas?
Answer: Ideal Gas Law: PV = nRT

Answer: 81.903 L

(Homework 8, #14)
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Question: If 68.5 moles of an ideal gas is at 2.93 atm and 493 K, what is the volume of the gas?
Answer: Ideal Gas Formula: PV = nRT

Answer: 946.266 L

(Homework 8, #15)
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Question: A mixture of helium, neon, and argon has a total pressure of 558 mmHg. If partial pressure of helium is 341 mmHg and th partial pressure of neon is 112 mmHg, what is the partial pressure of Argon?
Answer: Use Formula:

Total Pressure - (Sum of Component Pressures)

Answer: 105 mmHg

(Lecture 9, Slide 61)
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Question: A 8.65-L container holds a mixture of two gases at 49 °C. The partial pressures of gas A and gas B, respectively, are 0.371 atm and 0.769 atm. If 0.160 mol of a third gas is added with no change in volume or temperature, what will the total pressure become?
Answer: Use ideal gas law to find p. pressure of the third gas. Then sum all p. pressures to obtain new total pressure.

PV = nRT

Answer: 1.629 atm

(Homework 8, #18)
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Question: A gas mixture is made by combining 7.3 g each of Ar, Ne, and an unknown diatomic gas. At STP, the mixture occupies a volume of 17.31 L.
Answer: 1. Use STP Conversion FActor to convert from L to Moles: ! mol = 22.4 L

2. Find moles of components (Ar and Ne), Then subtract from total moles to find moles of Gas C

3. Divide mass of gas C (g) by moles of gas C to obtain molar mass

Answer: 31.96 g/mol

(Homework 8, # 19)
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Question: The combustion of octane, C8H18, proceeds according to the reaction:

2 C₈H₁₈(l) + 25 O₂(g) → 16 CO₂ + 18 H₂O(l)

If 498 mol C₈H₁₈ combusts, what volume of carbon dioxide is produced at 35.0 degrees Celsius and 0.995 atm?
Answer: 1. Convert to moles of CO₂ (2 mol C₈H₁₈:16 mol CO₂)

2. Use ideal gas law to find volume of CO₂

Answer: 1.01 x 10⁵ L

(Homework 8, #20)
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Question: Hydrazine, N2H4, may react with oxygen to form nitrogen gas and water:

N₂H₄ → N₂ + 2 H₂O

If 2.55 g of N2H4 reacts and produces 0.450 L of N2, at 295 K and 1.00 atm, what is the percent yield of the reaction?
Answer: 1. Find theoretical yield:
-Convert to moles N₂H₄
-Use equation to convert to moles N₂

2. Find actual yield using ideal gas law: PV=nRT
-Solve for n

3. Percent Yield=(Actual Yield/Theoretical Yield) x 100

Answer: 23.4%

(Homework 8, #21)
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Question: When aluminum is placed in concentrated hydrochloric acid, hydrogen gas is produced:

2 AL(s) + 6 HCl(aq) → 2 AlCl₃(aq) + 3 H₂(g)

What volume of H2(g) is produced when 7.50 g of Al(s) reacts at STP?
Answer: 1. Convert to moles of Al using p. table/m.mass
2. Use chemical equation to convert to moles of H₂
3. Use STP conversion to find volume of H₂

Answer: 9.341 L H₂

(Homework 8, #22)
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Question: In the following reaction, how many liters of carbon dioxide, CO2, measured at STP, would be produced from the decomposition of 379 g of magnesium carbonate, MgCO3?

MgCO₃(s) → MgO(s) + CO₂(g)
Answer: 1. Convert to moles of MgCO₃
2. Use chem. eq. to convert to moles of CO₂
3. Use ideal gas equation to find volume of CO₂

Answer: 100.748 L

(Homework 8, #23)
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Question: A 0.223 gram sample of a metal, M, reacts completely with sulfuric acid according to:

M(s) + H₂SO₄(aq) → MSO₄(aq) + H₂(g)

A volume of 233 mL (0.233 L) of hydrogen is collected over water; the water level in the collecting vessel is the same as the outside level. Atmospheric pressure is 756.0 Torr and the temperature is 25 °C. Calculate the molar mass of the metal.
Answer: 1. Because the H2(g) is collected over water, the pressure within the collecting vessel is due to both H2(g) and water vapor, Ptotal = PH2 Pwater. The vapor pressure of water at 25 °C is 23.8 Torr, and so:

P(H₂) = Total Pressure - Water Pressure
= 756.0 Torr - 23.8 Torr
= 732.2 Torr

2. The number of moles of H₂(g) collected is:

PV - nRT → n= (732.2Torr)(0.233L)/(62.3637L)(298K)
= 0.00918 mol H₂

3. According to the chemical equation, this also corresponds to the number of moles of metal, so use conversion factor of 1 mol M : 1 mol H₂ to convert to moles of M. (0.9918 moles M in this case)

4. Divide mass by moles to find g/mol.

0.223/0.00918 = 24.3 g/mol
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