Gas Laws Test
A 3.54 g sample of a certain diatomic gas occupies a volume of 3.30L at 1 atm and a temp of 45C. Identify this gas A. N2 B. O2 C. F2 D. H2 E. Cl2
A
A sample of N2 gas is contaminated with a gas (A) of unknown molar mass. The partial pressure of each gas is known to be 200 torr at 25 C. The gases are allowed to effuse through a pinhole, and it is found that gas A escapes at 4 times the rate of N2. The molar mass of gas A is: A. 1.75 B. 112 C. 7.01 D. 448 E. none
A
For which gas are the molecules diatomic A. He B. Cl2 C. Ch4 D. Nh3 E. All same
B
Calculate the density of nitrogen at STP A. 0.312 B. 0.625 C. 0.800 D. 1.25 E. 1.60
D
Calculate the ratio of the effusion rates of N2 and N2O A. 0.637 B. 1.57 C. 1.25 D. 0.798 E. 1.61
C
Determine the partial pressure of hydrogen gas in this mixture A. 562 torr B. 580 torr C. 598 torr D. 616 torr E. 634 torr
C
A sample of oxygen gas has a volume of 1.72 L at 27C and 800 torr. How many oxygen molecules does it contain? A. 4.43 x 10^22 B. 3.36 x 10^25 C. 4.92 x 10^23 D. 8.19 x 10^24 E. None
A
What volume does 40.5 g of N2 occupy at STP A. 64.8 L B. 1.81 L C. 32.4 L D. 50.7 L E. None
C
T/F gases behave most ideally at STP
False
Determine the number of moles of hydrogen gas present in the sample A. 42 mol B. 0.82 mol C. 1.3 mol D. 0.056 mol E. 22 mol
D
The purity of a sample containing zinc and weighing 0.312 g is determined by measuring the amount of hydrogen formed when the sample reacts with an excess of hcl acid. The determination shows the sample of 84% zinc. What amount of hydrogen was obtained? A. 2.62 x 10^-1 B. 1.30 x 10^-1 C. 4.77 x 10^-3 D. 2.41 x 10^21 molecules E. 2.41 x 10^21 atoms
D
Which contains the largest number of molecules? A. A B. B C. C D. All the same E. More info needed
D
Which of the following effects will make PV/nRt less than one for a real gas? A. the gas molecules are large enough to occupy a substantial amount of space B. a large number of molecules have speeds greater than the average speed C. the gas molecules have a very low molar mass D. the gas molecules attract one another E. none of these
D
Which of the following would have a higher rate of effusion than C2H2 A. N2 B. O2 C. Cl2 D. Ch4 E. CO2
D
Avagdros law states that: A. Equal amounts of gases occupy the same volume at constant temp and pressure B. The volume of a fixed amount of gas is inversely proportional to its pressure at constant temp C. The volumne of a fixed amount of gas is directly proportional to its temp at K D. The total pressure of a mixture of gases is the simple sum of the partial; pressure of all the gaseous compounds E. The rates of effusion of gases are inversely proportional to the square roots of their molar masses
A
Calcium hydride combines with water according to this equation ___ Beginning with 84 g of CaH2 and 42.0 g of H2O what volume of H2 will be produced at 273 K and a pressure of 1327 torr A. 29.9L B. 15.0L C. 5.39 x 10^2 L D. 25.7 L E. None
A
For which gas do the molecules have the highest average velocity A. He B. Cl2 C. Ch4 D. NH3 E. All same
A
Gaseous chlorine is held in 2 separate containers at identical temp and pressure. The volume of container is 1 to 1.30 L and it contains 6.70 mol of the gas. The volume of containers is 2 to 2.33. How many mols of gas are in the container A. 12.0 mol B. 20.3 mol C. 0.452 mol D. 3.74 mol E. None
A
Given N2 + 3H2 -> 2NH3 you mix 1 mol each of nitrogen and hydrogen gases under the same conditions. Calculate the ratio of volumes A. 0.67 B. 1.00 C. 1.33 D. 1.50 E. None
A
In which flask do the molecules have the highest average velocity A. A B. B C. C D. All same E. More info needed
A
It is found that 250 mL of gas at STP gas a mass of 0.700g. What is the molar mass A. 62.7 B. 2.80 C. 15.9 D. 11.2 E. 128
A
Of the following real gases, which would be expected to have the lowest van der waals correction for IMF A. H2 B. Cl2 C. NH3 D. O2 E. Not enough info
A
Which of the following is not a postulate of kinetic molecular theory A. Gas particles have most of their mass concentrated in the nucleus of the atom B. The moving particles undergo perfectly elastic collision with the walls of the container C. The forces of attraction and repulsion between the particles are insignificant D. The average kinetic energy of the particles is directly proportional to the absolute temp E. All of the above
A
You are holding 2 balloons. One is filled with Ne and the other Ar. The Ne has twice the volume of Ar. Which represents the mass ratios of Ne:Ar A. 1:1 B. 1:2 C. 2:1 D. 1:3 E. 3:1
A
You are holding 4 indentical balloons containing 10.0g of a different gas. The containing which gas is the largest balloon A. H2 B. He C. Ne D. O2 E. None
A
A gas sample is held at constant pressure. The gas occupies 3.62 L of volume when the temp is 21.6 C determine the temp at which the volume of the gas is 3.42 L A. 312 K B. 278 K C. 20.4 K D. 295 K E. 552 K
B
According to the postulates of the kinetic theory of gases, the average speed of the molecules of a given gas is proportional to the A. absolute temperature squared B. square root of the absolute temperature C. absolute temperature D. celsius temperature squared E. reciprocal of the absolute temperature
B
Boyles law states that: A. Equal amounts of gases occupy the same volume at constant temp and pressure B. The volume of a fixed amount of gas is inversely proportional to its pressure at constant temp C. The volume of a fixed amount of gas is directly proportional to its temp in K at constant pressure D. The total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds E. The rate of effusion of gases are inversely proportional to the square root of their molar masses
B
If a 17.9g sample of a gas occupies 10.0L at STP, what is the molar mass of the gas at 125C A. 5.48 B. 40.1 C. 18.4 D. 58.5 E. Not enough info
B
Real gases are those that A. only behave ideally at high pressure or low temperatures B. deviate from ideal behavior C. are only available naturally in the earth's atmosphere D. are called real gases because their behavior can easily be modeled E. have an even number of protons
B
The mass of 1.12 L of gas Y at Stp is found to be 6.23 g. The density of gas Y is A. 10.6 B. 5.56 C. 15.6 D. 0.200 E. 0.180
B
The van der Waals equation incorporates corrections to the ideal gas law in order to account for the properties of real gases. One of the corrections accounts for A. the possibility of chemical reactions between molecules B. the finite volume of molecules C. the quantum behavior of molecules D. the fact that average kinetic energy is inversely proportional to temp E. the possibility of phase changes when the temp is decreased or the pressure is increased
B
What volume of H2O measured at STP is produced by the combustion of 6.27g of natural gas according to the following equation? A. 8.76 L B. 17.5 L C. 4.38 L D. 19.1 L E. 3.14 L
B
What volume of carbon dioxide measured at stp will be formed by the reaction of 1.47 mol of oxygen with 0.900mol of ethyl alcohol A. 40.3 mL B. 22.0 L C. 32.9 L D. 49.4 L E. 0.980 L
B
What would happen to the average kinetic energy of the molecules of a gas sample if the temp of the sample increased from 20 to 40 C A. It would double B. It would increase C. It would decrease D. It would become half E. two of these
B
Which gas has the highest density A. He B. Cl2 C. Ch4 D. NH3 E. All same
B
You have a certain mass of He in a steel container, you add the same mass of Ne to this container. WHich of the following best describes what happened? Assume temp is constant A. The pressure dfoubles B. The pressure increases but does not double C. The pressure more than doubles D. The volume doubles E. The volume more than doubles
B
The valve between a 5L tank containing a gas at 9 atm and a 10L tank containing a gas at 6 atm is opened. Calculate the final pressure in the tanks A. 3 atm B. 4 atm C. 7 atm D. 15 atm E. None
C
The valve between the 2.00L bulb in which the gas pressure is 1.80 atm, and the 3.00L bulb, in which the gas pressure is 3.00 atm is opened. What is the final pressure in the two bulbs, the temperature is constant A. 0.720 atm B. 2.88 atm C. 2.52 atm D. 1.80 atm E. 2.40 atm
C
A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilizes at a height of 729mm above the pool of mercury. What is the pressure in the atmosphere A. 1.04 B. 0.729 C. 0.959 D. 456 E. 0.639
C
All of the following are postulates of the kinetic-molecular theory of gases except: A. the collisions between molecules are elastic B. the gas molecules are in constant motion C. at a constant temp each molecule has the same kinetic energy D. the volumes of the molecules are negligible compared with the volume of the container E. the gas molecules are in rapid motion
C
At 200K the molecules or atoms of an unknown gas X, have an average velocity equal to that of Ar atoms at 400K. What is X? A. He B. CO C. HF D. HBr E. F2
C
C2H4 + 3 O2 —> 2Co2 + H2O What volume of oxygen gas at STP is needed to react with 5.75 mol of C2h4 A. 17.3 B. 42.9 C. 3.86 x 10^2 D. 1.29 x 10^2 E. Not enough info
C
Consider a sample of gas in a containers on a comfy spring day. The C temp suddently doubles and you transfer the gas to a container with twice the volume of the first container. If the original pressure was 12 atm, what is the new pressure A. 3 atm B. 5.5 atm C. 6.4 atm D. 12 atm E. 15 atm
C
Consider the following containers, one with helioum at 27C and the other with argon at 27C, which of the following statements is true A. The speed of each atom of helium is 926 m/s B. The rms speed of the He and the Ar atoms are the same C. The average kinetic energy of the two samples are equal D. All of the above are true E. None of the above are true
C
For an ideal gas which pairs of variables are inverselt proportional to each other 1. V and t 2. T and n 3. N adn v 4. P and T A. 1 and 2 only B. 3 and 4 only C. 2 only D. 1 and 3 only E. 1 3 and 4
C
Given 2NH3 + 3CL2 -> N2 + 6HCl you react 5.0 L of Nh3 with 5.0L of Cl2 measured at the same conditions in a closed container. Calculate the ratio of the pressures A. 0.75 B. 1.00 C. 1.33 D. 1.50 E. None
C
In which flask are the molecules least polar and therefore most ideal in behavior? A. A B. B C. C D. All the same E. More info needed
C
Oxygen gas generated by the reaction 2KCLO3 —> 2KCL + 3O2 is collected over water at 27C in a 1.55L vessel at a total pressure of 1.0 atm. How many mols of KClO3 were consumed in this reaction A. 0.0608 B. 0.0912 C. 0.0405 D. 0.0434 E. 1.5
C
The mass of 1.12 L of gas Y at stp is found to be 6.23 g. The molar mass of gas Y is A. 56 B. 89 C. 125 D. 140 E. 157
C
Which of the following statements is true concerning ideal gases? A. The temp of the gas sample is directly related to the average velocity of the gas particles B. At STP 1.0L of Ar contains about twice the numbers of atoms as 1.0 L of Ne since the molar mass of Ar is about twice od that of Ne C. A gas exerts pressure as a result of the collision of the gas molecules with walls of the container D. The gas particles in a sample exert attraction forces for one another E. All of the above are false
C
You have 41.6 g of O2 gas in a container with twice the volume as one with Co2 gas. The pressure and temp of both containers are the same. Calculate the mass of Co2 A. 57.2 g B. 0.650 g C. 28.6 g D. 2.60 g E. None of these
C
A gaseous mixture contaoining 1.5 mol Ar and 3.5 mol Co2 has a total pressure of 7.3 atm. What is the partial pressure of CO2 A. 2.2 atm B. 1.4 atm C. 17 atm D. 5.1 atm E. 7.3 atm
D
A physics experiment is conducted at a pressure of 14.4 kPa What is the pressure in mmHg A. 18.9 B. 1.92 C. 1.44 x 10^4 D. 108 E. 1.89 x 10^-2
D
A vessel with a volume of 26.9L contains 2.8g of nitrogen gas, 0.605 g of hydrogen gas, and 79.9 of argon gas. At 25C what is the pressure in the vessel A. 75.5 B. 0.183 C. 2.55 D. 2.18 E. 58.7
D
Dalton's law of partial pressure states that: A. Equal amounts of gases occupy the same volume at a constant temp and pressure B. The volume of a fixed amount of gas is inversely proprotional to its pressure at constant temp C. The volume of a fixed amount of gas is directly proportional to its temp in K D. The total pressure of a mixture of gases is the sum of the partial pressure of all the gaseous compounds E. The rates of effusion of gases are inversely proportional to the square toor of their molar masses
D
Pressure is A. Defined as the mass that an object exerts when at rest B. Measured in newtons C. Defined as the number of moles of susbtance divided by the mass of the substance D. Defined as force per unit area E. Measured in grams
D
A 142 mL sample of gas is collected over water at 22C and 753 torr. What is the volume of the dry gas at STP? A. 122mL B. 162mL C. 136mL D. 111mL E. None
E
For a gas which two variables are directly proportional to each other 1. T and n 2. V and n 3. V and T A. 1 only B. 2 only C. 3 only D. 1 and 2 only E. 2 and 3 only
E
For which gas are the collisions elastic? A. He B. Cl2 C. Ch4 D. Nh3 E. All same
E
For which gas do the molecules have the smallest average kinetic energy A. He B. Cl2 C. Ch4 D. Nh3 E. All same
E
Grahams law states that A. equal amounts of gases occupy the same volume at constant temperature and pressure B. the volume of a fixed amount of gas is inversely proportional to its pressure at constant temp C. the volume of a fixed amount of gas is directly proportional to its temp in K D. the total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds E. the rates of effusion of gases are inversely proportional to the square roots of their molar masses
E
The SI unit of pressure is the A. Ampere B. Kilojoule C. Newton D. Gram E. Pascal
E
Which conditions of P T and n respectively are most ideal? A. High P high T high n B. Low P low T low n C. High p low T high n D. Low P high T high n E. Low p high T low n
E
Which gas sample has the greatest number of molecules A. He B. Cl2 C. CH4 D. Nh3 E. All same
E
T/F At the same temperature, lighter molecules have a higher average kinetic energy than heavier molecules
False
T/F The pressure a gas would exert under ideal conditions is always greater than the observed pressure of a real gas
False
T/F the diffusion of a gas is faster than the effusion of a gas
False
t/f in the kinetic molecular theory we assume an ideal gas has no mass
False
