CHEMISTRY EXAM

The Maxwell Boltzmann distributions of molecular speed examples of two different gases at the same temperature as shown above. Which gas has the greater molar mass?

gas A

Which of the following most likely describes the solid represented in the diagram above?

it is a brittle, water soluble electrolyte that is a poor thermal and electrical conductor as a solid.

compared to the equilibrium vapor pressure of CH30H at 300 K, the equilibrium vapor pressure of C2 H50H at 300 K is?

lower, because London dispersion forces among C2 H5 OH molecules are greater than those among CH30H molecules.

The massive see you produced in step three was slightly more than the mass protected from the 3.8Grams of CU three recovered from step one. Which of the following could account for the discrepancy in the yield of Cu from step three?

some unreacted ZN was mixed in the Cu

In an experiment a student makes us 50 mL sample of .1 M AgNO3 with a 15 mL sample of .1 MNACL at 20°C in a coffee cup calorie meter. Which of the following is the end will be change of the precipitation reaction to represent it above the final temperature of the make sure it's 21° C?

-84 kj

The temperature of CH3OH Is increased from 300 K to 400 K to vaporize all the liquid which increases the pressure in the vessel to .3 ATM. The experiment is repeated under identical conditions but this time using half the mass of CH30H that was used originally. What will the pressure in the vessel at 400 K

.15 ATM

The value of K for the evaporation of CH3OH at 300k is closet to ?

.2

if 3.8 g of CU three was recovered from step one, what was the approximate see you too in the original solution?

.3 M

The pH of a solution made by combining 150 mL of .10 mL of .10 M KOH with 50 mL of .2 M HBr is closest to which of the following?

12

On the basis of information above, what is the approximate percent ionization of HNO2 in 1.0 M HNO2 solution?

2.0%

Which of the following best describes the change that takes place immediately after the CH3OH is introduced into the previously evacuated vessel?

A physical change takes place because intermolecular attractions are overcome.

dissolution of the slightly soluble salts is shown by the equation above which of the following changes would decrease CA in a saturated solution of CIP three and why?

Adding an AF because the reaction will proceed toward reactants.

A 1.0 L sample of a pure gas is found to have a lower pressure than that predicted by the ideal gas law. The best explanation for the observations is that the molecules of the gas.

Are attracted to each other and do not exert as much force on the container walls as they would if they had no mutual attractions.

when a small amount of 12 MHNO3 is added to a buffer solution made by mixing CH3NH2 and CH3NH3, The pH of the buffer solution changes from 10.64 to 10.62. Which of the following equations represents the reaction that accounts for the fact that the pH does not change significantly when the HNO3 is added?

CH3NH2 + H = CH3NH3

Equal volumes of solutions in two different vessels are represented above. If the solution represented in vessel 1 is KCL, then the solution represented in vessel 2 could be an aqueous solution of

CaCl2 with twice the molarity of the solution in vessel 1

The standard reproduction potentials for half-reaction related to the galvanic cell represented above are listed in the table below...

E= =.002 V

A 20 mL sample of .5 M HC2H3O2 is titrated with .5 M NaOH. Which of the following best represents the species that react and the species produced in the reaction?

HC2H3O2 + OH = C2H3O2 + H2O

Three substances were studied in the laboratory, and the data in the table above were collected. Based on the date, which of the following shows the type of bonding in each substance?

Network covalent, Metallic, Ionic

For which of the equilibrium systems represented below with the amount of products at equilibrium increase of the volume of the reaction vessel is increased at a constant temperature?

PCl5

The values of the disassociation Constance for the H3 PO four are given in the table above. Given that the solution in the beaker at the end of step two had a pH of approximately one, which of the following chemical species has the lowest concentration among the products of step two?

PO4 3

Equal more samples of PB, PBI to, and PDF to you, are placed in three separate bakers, each containing 250 mL of water at 25°C. After the solutions are sturdy, salad remains in the bottom of each beaker. Based on the K values for the compound was it on the table above, a solution of which of the compounds will have the lowest PB?

Pb(OH)2

Based on the information in the table above, which of the compounds has the highest boiling point, and why?

Propanoic acid, because it can form intermolecular hydrogen bonds

The equation above represents an elementary step in a chemical reaction. Which of the following is the correct expression for the rate law of the elementary step?

Rate = k[NOBr]2

Based on coulombs law the information in the table above, which of the following anions is most likely to have the strongest interactions with nearby water molecules in aqueous solution?

S2

The masses of carbon dioxide and hydrogen in samples of four pure hydrocarbons are given above. The hydrocarbon in which samples has the same empirical formula as propene, C3H6?

Sample B

which of the following best helps explain why CCL for is a liquid were a seal for is a salad when both are at 25°C?

The London dispersion forces are stronger in CI4 than in CCI4 because CI4 has a more polarizable electron cloud and CCI4.

Which of the following correctly compares periodic properties of two elements and provide an accurate explanation for that difference?

The atomic radius of Cl is smaller than than that of S because Cl has a larger nucleus than S does.

A balloon filled with .25 mol of He at 273 K and 1 atm is allowed to rise through the atmosphere. Which of the following explains what happened to the volume of the balloon as it rises from ground level to an altitude where the air temperature 220K and the air pressure is .1 atm?

The volume will decrease because the decrease in air pressure will have a greater effect than the decrease in temperature.

The ionization energies of an unknown element, X, are listed in the table above. Which of the following is the most likely empirical formula of a compound formed from element X and phosphorus P?

X3P2