Chemistry Final Exam

Which statements) regarding electromagnetic radiation are correct? a. electromagnetic radiation consists of oscillating electric and magnetic fields b. electromagnetic radiation has a relationship between energy, frequency, and wavelength. c. not all electromagnetic radiation is visible to the eye d. electromagnetic radiation spans a very wide range of wavelengths, from gamma rays to radio waves e. all statements are correct

e. all statements are correct

Which transition in a hydrogen atom requires the smallest change in energy? E = -2.178 x 10^-18J(1/n2 final - 1/n2intial) a. n1= 1 to n2=2 b.n= 3 to n2=4 c. n1= 2 to n2=3 d. n1= 3 to n2=5 e. n1= 4 to n2=5

e. n1= 4 to n2=5

Oxygen is best described as a(n) a. metalloid. b. transition metal. c. chalcogen. d. alkaline earth metal. e. nonmetal.

e. nonmetal.

How many hydrogen atoms are in a 346 g sample of pure ammonia (NH3)? a. 3.67 × 10^25 atoms b. 1.22 x 10^25 atoms c. 60.9 atoms d. 20.3 atoms e. 4.89 x 10^25 atoms

a. 3.67 × 10^25 atoms

8. The concentration (in % by volume) of methyl tert-butyl ether (MTBE) was determined in four samples of the same gasoline. What is the average value, and which measurement was the most accurate, compared to the average? Sample % (v/v) MTBF 1- 5.01 = 2- 4.95= 3- 5.10= 4- 5.15= a. 5.05, sample 1 b. 5.05, sample 2 c. 5.05, sample 3 d. 5.05, sample 4 e. 5.0525, sample 3

a. 5.05, sample 1

You are a technician in an analytical laboratory and are asked to determine from its density whether an antique coin might be gold. You weigh the coin and find that its mass is 84.6419 g. When you place the coin in a graduated cylinder containing 105.53 mL of water, the water level rises to 114.64 mL. Calculate the density of the coin from your measurements, and determine how many significant figures should be included in the reported result. Which of the following numbers will you put in your report for the density of the coin? a. 9.29 g/mL b. 9.3 g/mL c. 0.73833 g/mL d. 9.2911 g/mL e. 9.29109769 g/mL

a. 9.29 g/mL

If each of the following metals is exposed to light with a wavelength of 240 nm, which willemit photoelecfrons with the greatest kinetic energy? a. iron (Ф=72 x 10^-19J) b. platinum (Ф=9.1 x 10^-19 J) c. nickel (Ф=0.3 × 10^-19 J) d. pattadiam (Ф-8.2x 10^-19 ) e. sodium (Ф=4.4 x 10^-19 J)

e. sodium (Ф=4.4 x 10^-19 J)

Enriched weapons-grade uranium consists of 80% uranium-235 (235.044 amu) and 20% uranium-238 (238.051 amu). What is the average atomic mass of weapons-grade uranium, assuming the percentages are exact? a. 235.044 amu b. 236.547 amu c. 238.051 amu d. 235.645 amu e. 235.754 amu

d. 235.645 amu

{55/25Mn has ___ protons, ___ neutrons, and ___electrons. a. 30: 55; 25 b. 25: 30; 55 c. 30: 25: 25 d. 25: 30; 25 e. 30; 25; 30

d. 25: 30; 25

What is the energy of the photons emitted by an Ar* laser with a wavelength of 1= 488 nm?) a. 2.46 x 10^18 J b. 9.69 × 10^-23 J c. 1.36 x 10^-36 J d. 4.07 x 10^-19 J e. 2.46 x 10^-18 J

d. 4.07 x 10^-19 J

What is the orbital designation for an electron with the quantum numbers n= 4, |= 3? a. 4s b. 4p c. 4d d. 4f e. cannot determine from the given information

d. 4f

Commercial hydrochloric acid is 12.1 M. What volume of commercial HCI solution should we used to prepare 250.0 mL of 3.00 M HCI? a. 139 mL b. 126 mL C. 252 mL d. 62 ml e. 83 mL

d. 62 ml

A mass of 1,60 g of phosphoric ad was produced trom the reacion of 10.00 g of P. Ore with 12.00 g water. What was the percent yield for this reaction? a. 78.62% b. 101.1% c. 92.70% d. 84.00% e. 52.70%

d. 84.00%

What is the molar mass of sulfuric acid (H2SO4)? a. 49.0 g/mol b. 24.5 g/mol c. 101 g/mol d. d. 98.1 g/mol e. 97.0 g/mol

d. 98.1 g/mol

A compound was analyzed and found to contain 25.24% S and 74.76% F. What is the empirical formula for the molecular compound? a. SF b. SF2 c. SF3 d. SF5 e. S2F4

d. SF5

Which of the following photons has the highest frequency? a. a photon from an Nd:YAG laser with A= 1,064 nm b. a photon from an Ar+ laser with y=514.5 nm c. a photon from a Kr+ laser with y=.647 nm d. a photon from an ArF laser with y= 193 nm e. a photon from an He-Ne laser with y= 693 mm

d. a photon from an ArF laser with y= 193 nm

Which of the transitions in the hydrogen atom energy-level diagram shown here is not possible? a. n=5 b. n=2 c. n=3 d. between n = 2 and n = 3 e. all are possible

d. between n = 2 and n = 3

What is the proper name for Co3P2? a. cobalt(Ill) phosphide b. tricarbon diphosphate c. cobalt diphosphide d. cobalt(lI) phosphide e. tricobalt diphosphide

d. cobalt(lI) phosphide

Which statement best summarizes the Heisenberg uncertainty principle? a. the mass and velocity of an electron in an atom are known precisely b. the mass and momentum of an electron in an atom cannot both be precisely known c. the mass and position of an electron in an atom cannot both be precisely known d. the position and momentum of an electron in an atom cannot both be precisely known e. the position and energy of an electron in an atom cannot both be precisely known

d. the position and momentum of an electron in an atom cannot both be precisely known

Sea water contains roughly 35 g of salts (mostly sodium chloride) per 1 L of water. The solute is: a. water b. the same as the solution c. concentrated d. the salts e. sea water is not a solution

d. the salts

Elements 21-30 are known as a. alkaline earth metals b. chalcogens c. halides d. transition metals e. rare earths

d. transition metals

Aqua regia is a mixture of hydrochloric acid and nitric acid that is capable of dissolving gold. What are the formulas of these acids? a. HCIO, HNO4 b. HCIO4, HNO3 c. HCI, HNO2 d.HCI, HNO3 e. HCI, HNO

d.HCI, HNO3

A sample of Ar gas at 35 °C occupies a volume of 1.50 L at a pressure of 3.2 atm. How many moles of the gas are present in the sample? a. 3.32 mol b. 0.599 mol c. 5.26 mol d.1.67 mol e. 0.190 mol

e. 0.190 mol

Which of the following statements) regarding the quantum numbers that identify an atomic orbital are correct? a. The angular momentum quantum number, I, can have integer values between (-1) and zero b. The magnetic quantum number, mi, can have values that range from -I to +I in integer steps c. an s orbital of any given shell has only one possible mI value d. for p orbitals of any given shell, there are five possible mI values e. all statements are correct

e. all statements are correct

Most chloride salts are soluble. Identify an exception to this generalization. a. AgCl b. CaCl c. MgCl2 d.BaCl2 e. NaCl

AgCl

In the following reaction, which element or ion is reduced? Cl2(g) + 2NaBr(aq) -> 2NaCI(aq) + Br2(g) a. Br2 b. Na+ c. Cl2 d. Br- e. Cl-

Cl2

A barometer measures a pressure of 745 mmHg. What is this pressure in atm? a. 0.980 atm b. 1.02 atm c. 1.03 x 10^5 atm d. 1.00 x 10^4 atm e. 0.556 atm

a. 0.980 atm

Water can be separated into its elements by electrolysis according to the following equation. If 20.0 g of water is decomposed by this method, how much oxygen gas is produced? 2H,0(1) -> 2H,(g) +02(g) a. 17.8 g b. 8.9 g c. 35.6 g d. 16.0 g e. 10.0 g

a. 17.8 g

A sealed gas, initially at 5.00 atm and 5.00 L, expands to a volume of 10.00 L. What is the new pressure of the gas, assuming constant temperature? a. 2.50 atm b. 25.0 atm c. 5.00 atm d. 10.0 atm e. 50.0 atm

a. 2.50 atm

Baking a cake requires 16 teaspoons of vegetable oil. How many fluid ounces is that? (1 cup = 48 teaspoons and 1 cup = 8 fl oz) a. 2.7 fl oz b. 96 fl oz c. 4.1 × 10-2f1 oz d. 0.38 fl oz e. 24 fl oz

a. 2.7 fl oz

What volume is occupied by 1.00 mol of an ideal gas at standard temperature and pressure? a. 22.4 L b. 22.7 L c. 22.1 L d. 15.0 L e. 27.2 L

a. 22.4 L

Which of the following is an alkali metal? a. K b. Mg c. Al d. Cu e. Sc

a. K

Which of the following statements) regarding a strong acid is correct? a. a strong acid ionizes completely in water b. strong acid ionizes in water to produce hydroxide ions c. a strong acid neutralizes only strong bases d. CH3COOH is an example of a strong acid e. acids are only strong at a high concentration

a. a strong acid ionizes completely in water

1. A pure substance: a. cannot be separated into simpler substances by physical means b. can have a composition that varies from sample to sample. c. must be an element d. has different chemical and physical properties depending on its source. e. must be a compound.

a. cannot be separated into simpler substances by physical means

What are the units of molarity, M? a. mol/L b. g/L C. mol/kg d. ppm e.mol/mL

a. mol/L

Which of the following is unimportant when using the ideal gas law? a. the chemical identity of the gas sample b. the temperature of the gas sample c. the pressure of the gas sample d. the volume of the container holding the gas sample e. the amount of gas

a. the chemical identity of the gas sample

When 10.0 mL of a 0.10 M solution of HCI are diluted to a volume of 20.0 mL, what remains unchanged? a. the moles of HCI in the solution b. the concentration of the HCI solution C. the volume of the HCI solution d. the mass of the HCI solution e. the moles, concentration, volume, and mass of the solution all change

a. the moles of HCI in the solution

A 25.0 L balloon is filled with 2.75 mol of helium. If the helium leaks out at the rate of 0.105 mol/hr, what is the volume of the balloon after 12.0 hr? Assume pressure and temperature don't change. a. 111.5 L b. 13.5 L c. 23.7 L d. 1.26 L e. 17.4 L

b. 13.5 L

What is the wavelength of a radio station operating at a frequency of 99.6 Hz? a. 3.01 m b. 3.01 x 10^8 m c. 3.32 x 10^-7 m d. 0.332 m e. 3.32 m

b. 3.01 x 10^8 m

Which statement is correct? a. Electrons, protons, and neutrons have about the same mass. b. Electrons have a much smaller mass than protons and neutrons, c. Neutrons are much more massive than protons. d. Protons are much more massive than neutrons. e. Electrons have a much larger mass than protons and neutrons.

b. Electrons have a much smaller mass than protons and neutrons,

In which compound does chlorine have an oxidation number of +5? a. HCIO4. b. HCIO3 c. HClO2 d. HCIO e.HCl

b. HClO3

Identify the base in the following acid-base reaction. NaNO2(aq) + HI(aq) -> Nal(aq) + HNO2(aq) A. Na+ b. NO2 c. I- d. HI e. HNO2

b. NO2

Which of the following molecular compounds is named correctly? a. PCIs, phosphorus(IlI) chloride b. Na2Br4, dinitrogen tetrabromide c. P2N5, phosphorus pentanitride d. NO, nitrogen oxide monoxide e. SO2, sulfur(lI) oxide

b. Na2Br4, dinitrogen tetrabromide

Based on the element's position in the periodic table, which statement is correct? a. The charge on an ion of sodium is 1-. b. The charge on an ion of magnesium is 2+. c. The charge on an ion of oxygen is 2+ d. The charge on an ion of chlorine is 2- e. Ca2+ has more electrons than Ar.

b. The charge on an ion of magnesium is 2+.

When are an empirical formula and a molecular formula the same? a. always b. when the mass of the empirical formula unit is equal to the molecular mass c. when the mass percentages of all the elements in the two formulas are the same d.never e. when the molecular mass is an integer multiple of formula unit mass

b. when the mass of the empirical formula unit is equal to the molecular mass

How many grams of solid magnesium chloride, MgCk, are needed to make 250 mL of 0.50 M solution? a. 9.5 g b. 48 g c. 12 g d. 12.5 g e. 4.8 g

c. 12g

Phosphorus trichloride reacts with water to form phosphorous acid, H3PO4, and hydrochloric acid in the following unbalanced reaction. For each mole of phosphorous acid produced by this reaction, how many moles of HCI are produced? _ PCI3+ _ H20 -> _ Н3PO3 + _ HCl a. 1 b. 2 c. 3 d. 4 e. 5

c. 3

A sample of water (H20) contains 1.81 x 1024 molecules. How many total moles are in this sample? a. 1.00 b. 2.00 c. 3.00 d. 6.00 e. 9.00

c. 3.00

The I= 2 subshell contains how many total orbitals? a. 1 b. 3 c. 5 d. 7 e. 9

c. 5

Even though lead is toxic, lead compounds were used in ancient times as white pigments in cosmetics. What is the percentage of lead by mass in lead(IV) carbonate, Pb(CO3)2? a. 32.7% b. 20.7% c. 63.3% d. 77.5% e. 81.4%

c. 63.3%

Magnesium hydroxide is insoluble. Write the net ionic equation for the reaction that takes place between a solution of magnesium chloride and a solution of sodium hydroxide. a. MgCl2(aq) + NaOH(aq) -> MgOH(s) + NaCl2(aq) b. MgCl2(aq) + 2NaOH(aq) -> Mg(OH)2(s) + 2NaCI(aq) c. Mg2+(aq) + 20H-(aq) -> Mg(OH)2(s) d. Mg2+(aq) + 2Cl-(aq) + 2Na*(aq) + 20H-(aq) -> Mg(OH)2(s) + 2NaC|(aq) e. Mg2+(aq) + OH-(aq) -> MgOH(s)

c. Mg2+(aq) + 20H-(aq) -> Mg(OH)2(s)

Which of the following gases has nearly the same density as COz at room temperature and atmospheric pressure? a. N2 b. O2 c. N2O d. Ar e. CO

c. N2O

2. A heterogeneous mixture: a. can only be separated into its components by chemical methods. b. involves substances solely in the gas phase. c. has non-uniform sample composition. d. exclusively refers to substances in the same phase. e. is also called a solution.

c. has non-uniform sample composition.

In a mixture of gases, the gas with the largest mole fraction will have the: a. largest molar mass b. smallest molar mass c. largest number of molecules present d. smallest number of molecules present e. highest kinetic energy

c. largest number of molecules present

The temperature of a gas is directly proportional to a. the number of moles of the gas b. the identity of the gas c. the volume of the gas d. the density of the gas e. the mass of the gas

c. the volume of the gas

Which of the following quantities has two significant figures? a. 0.4 b. 101. c. 1.10 × 103 d. 0.0092 e. 0.520

d. 0.0092

Medicines usually are dispensed in units of mg. What is the mass (in grams) of a 50 mg tablet? a. 50 g- b. 5.0 g c. 0.50 g d. 0.050 g e. 0.0050 g

d. 0.050 g

A gas mixture has partial pressures of 120 torr N2, 350 torr Ar, and 480 torr SF6. What is the mole fraction of sulfur hexafluoride in the mixture? a. 0.13 b. 0.37 c. 0.45 d. 0.51 e. 0.55

d. 0.51

Identify the set of stoichionhetric coerficients that balances the equation for the following combustion reaction: _ Cr10H20 + _ 02 -> __ CO2 + __ H20 a. 1, 7.5,5, 10 b. 2, 30, 20, 20 c. 1, 30, 10, 20 d. 1, 15, 10, 10 e. None of these coefficients balance the reaction equation.

d. 1, 15, 10, 10

The following measurements of the mass of an aspirin tablet were made by different students in a lab. Which set is the most precise? a. 1.513 g, 1.503 g, 1.522 g b. 1.513 g, 1.511 g, 1.450 g c. 1.513 g, 1.459 g, 1.533 g d. 1.513 g, 1.517 g. 1.512 g e. 1.513 g, 1.510 g, 1.523 g

d. 1.513 g, 1.517 g. 1.512 g

Automobile air bags inflate during a crash or sudden stop by the rapid generation of nitrogen gas from sodium azide. 2 NaNa(s) -> 2 Na(s) + 3 N2(g) How many moles of sodium azide are needed to produce enough nitrogen to fill a 50.0 L air bag to a pressure of 1.25 atm at 25 °C?) a. 2.56 mol b. 3.83 mol c. 5.31 mol d. 1.70 mol e. 4.92 mol

d. 1.70 mol

Liquid nitrogen boils at 77 K. What is this temperature in °F? a. -196°F b. -321°F c. -256°F d 77°F- e. -352°F

b. -321°F

What mass of phosphoric acid (HyPO4, 98.00 g/mol) is produced from the reaction of 10.00 g of P4010 (283.89 g/mol) with 12.00 g water? a. 10.90 g b. 0.14 g c. 43.52 g d. 13.81 g e. 14.52 g

d. 13.81 g

Children's pinewood derby cars race on 45 ft tracks. If a car takes 3.25s to travel down the track, how many miles per hour (mph) is the car racing? (1 mi = 5280sq ft) a. 0.00852 mph b. 9.44 mph c. 30.7 mph d. 13.8 mph e. 0.315 mph

b. 9.44 mph

16O, 17O, and 18O are all examples of..... because they have different numbers of a. isotopes; protons b. isotopes; neutrons c. isotopes; electrons d. allotropes; neutrons e. allotropes; protons

b. isotopes; neutrons

3. An example of a physical property of formaldehyde (CH20) is: a. it has a density of 1.09 g/mL. b. it is colorless. c. it dissolves in water. d. it is a gas at room temperature. e. all of the above are physical properties.

e. all of the above are physical properties.