FiltersDone

Question type

Essay

Multiple Choice

Short Answer

True False

Matching

Exam 5: Gases

Show Answer

Share

---

All types

Filters

Study FlashcardsPractice ExamLearn

Question 31

Multiple Choice

Review LaterAdd Note

Review Later

A 1.17 g sample of an alkane hydrocarbon gas occupies a volume of 674 mL at 28°C and 741 mmHg.Alkanes are known to have the general formula CnH2n+2.What is the molecular formula of the gas in this sample? (R = 0.08206 L.atm/K.mol)

A) CH₄
B) C₂H₆
C) C₃H₈
D) C₄H₁₀
E) C₅H₁₂

Correct Answer

verified

Show Answer

Question 32

Short Answer

Review LaterAdd Note

Review Later

A convenient way to produce very high purity oxygen in the laboratory is to decompose KMnO₄(s)at high temperature according to the following chemical equation: 2KMnO₄(s) $\rarr$ K₂MnO₄(s)+ MnO₂(s)+ O₂(g) If 2.50 L of O₂(g)is needed at 1.00 atm and 20°C, what mass of KMnO₄(s)should be decomposed? Assume the decomposition of KMnO₄(s)goes to completion.

Correct Answer

verified

Show Answer

Question 33

Multiple Choice

Review LaterAdd Note

What is the pressure of the gas trapped in the apparatus shown below when the atmospheric pressure is 720 mmHg?

A small bubble rises from the bottom of a lake, where the temperature and pressure are 4°C and 3.0 atm, to the water's surface, where the temperature is 25°C and the pressure is 0.95 atm.Calculate the final volume of the bubble if its initial volume was 2.1 mL.

A 2.50-L flask contains a mixture of methane (CH₄) and propane (C₃H₈) at a pressure of 1.45 atm and 20°C. When this gas mixture is then burned in excess oxygen, 8.60 g of carbon dioxide is formed. (The other product is water.) What is the mole fraction of methane in the original gas mixture?

Air contains 78% N₂, 21% O₂, and 1% Ar, by volume. What is the density of air at 1,000.torr and -10°C?

Phosgene, a chemical warfare agent used in World War I, consists of 12.41% C, 16.17% O, and 71.69% Cl.1.00 L of this gas at STP has a mass of 4.42 g. What is the molecular formula of phosgene?

Calculate the volume occupied by 35.2 g of methane gas (CH₄) at 25°C and 1.0 atm.R = 0.08206 L.atm/K.mol.

At standard temperature and pressure, a given sample of water vapor occupies a volume of 2.80 L. How many moles of water vapor are present?

Packaged cake mixes usually contain baking powder, a mixture of sodium hydrogen carbonate and calcium hydrogen phosphate that react to produce carbon dioxide gas when they are heated in water.The CO₂(g)formed allows the cake to "rise." When such cake mixes are used at high altitudes, often the cake will rise too much and collapse, unless special instructions are followed.Why does this happen?

Which of these gases will have the greatest density at the same specified temperature and pressure?

A sample of N₂ gas occupies 2.40 L at 20°C. If the gas is in a container that can contract or expand at constant pressure, at what temperature will the N₂ occupy 4.80 L?

A pressure that will support a column of Hg to a height of 256 mm would support a column of water to what height? The density of mercury is 13.6 g/cm³; the density of water is 1.00 g/cm³.

A sample of carbon monoxide gas was collected in a 2.0 L flask by displacing water at 28°C and 810 mmHg. Calculate the number of CO molecules in the flask. The vapor pressure of water at 28°C is 28.3 mmHg.

What volume of CO₂ gas at 645 torr and 800 K could be produced by the reaction of 45 g of CaCO₃ according to the equation? CaCO₃(s) $\rarr$ CaO(s) + CO₂(g)

Calculate the volume of H₂(g) at 273 K and 2.00 atm that will be formed when 275 mL of 0.725 M HCl solution reacts with excess Mg to give hydrogen gas and aqueous magnesium chloride.

Which of these gas molecules have the highest average kinetic energy at 25°C?

If the pressure of a gas sample is quadrupled and the absolute temperature is doubled, by what factor does the volume of the sample change?

A gaseous compound is 30.4% nitrogen and 69.6% oxygen by mass. A 5.25-g sample of the gas occupies a volume of 1.00 L and exerts a pressure of 1.26 atm at -4.0°C. Which of these choices is its molecular formula?

What is V in the table below?