Which of the following elements is incorrectly labeled as a metal, metalloid, or nonmetal?
a. Sulfur (S) is a metalloid
b. Silicon (Si) is a metalloid
c. Nitrogen (N) is a nonmetal
d. Lead (Pb) is a metal
a. Sulfur (S) is a metalloid
Technetium-99 used for medial diagnostic tests and has a half life of 6.0 hrs. How long does it take 120 mg of technetium-99 to decay to 7.5 mg?
a. 24 hrs
b. 18 hrs
c. 12 hrs
d. 30 hrs
a. 24 hrs
How many total lone pairs of electrons are in the ion BrO2?
a. 2
b. 7
c. 6
d. 4
e. 8
e. 8
What is the molarity of a KCl solution made by diluting 75.0 mL of a 0.200 M solution to a final volume of 100. mL?
a. 0.100 M
b. 0.125 M
c. 6.67 M
d. 0.150 M
d. 0.150 M
Which of the pairs below represents an acid followed by its conjugate base?
a. CN-/ HCN
b. NH4+ / NH3
c. Na2CO3 / CO32-
d. HCl / NaOH
b. NH4+ / NH3
Which of the following are chemical changes?
a. rusting of a nail
b. freezing of water
c. decomposition of water into hydrogen and oxygen gases
d. compression of oxygen gas
a & c
Which isotope, when bombarded with nitrogen-15, produces dubnium-260 and 4 neutrons?
157 N + _____ --> 260105 Db + 4 10 n
a. 24698 Cf
b. 246113 Cf
c. 24694 Pu
d. 24998 Cf
d. 24998 Cf
a. carbon chloride CCl4
b.oxygen difluoride OF2
c. quadphosphorous trisulfide P4S3
d. nitrogen nitrate NO2
b.oxygen difluoride OF2
What is the pressure, in atm, of a 4.00 g sample of O2 gas, which has a temp of 303.2 K and a volume of 3.00 L?
a. 0.103 atm
b. 3.11 atm
c. 33.2 atm
d. 1.04 atm
d. 1.04 atm
Which of the statements below is true concerning the solutions A and B?
solution A: 0.10 M HNO2 that has a Ka of 4.5 x 10-4
solution B: 0.10 M H2S that has a Ka of 9.8 x 10-8
a. both solutions are equally acidic
b. solution A and B are both strong acids
c. solution A and B are not acids
d. solution A is more acidic than solution B
d. solution A is more acidic than solution B
The typical human heart pumps approximately 75 mL of blood per beat. Assuming an average pulse of 73 bpm, how many hours will it take the heart to pump 5.20 x 105 mL?
a. 95 h
b. 8400 h
c. 1.6 h
d. 5.7 h
c. 1.6 h
What type of radiation is generated from the following decay reaction?
9942 Mo --> 9943 Te + 0-1 e
a. alpha
b. neutron
c. positron
d. gamma
e. beta
e. beta
When is the following unbalanced chemical equation is balanced, what is the coefficient associated with water?
P4O10 (s) + H2O (l) --> H3PO4 (aq)
a. 6
b. 4
c. 12
d. 2
a. 6
Which combination of aq will form a precipitate when mixed together?
a. NaOH & KNO3
b. NaCl & Zn(NO3)2
c. NaNO3 & ZnCl2
d. NaOH & Zn(NO3)2
d. NaOH & Zn(NO3)2
Which of the following is not true about a buffer solution?
a. solution that can contain both a weak base and its conjugate acid
b. solution that resists changes in pH when an acid is added
c. solution that regulates pH bc it is such a strong acid or strong base
d. solution that resists changes in pH when a base is added
c. solution that regulates pH bc it is such a strong acid or strong base
Which of the following statements is false?
a. Energy level 4 has 4 sublevels
b. The 3p & 4p orbitals have different energy
c. All 5 d orbitals each have the same energy level
d. All 5 d orbitals have the same 3-D shape
d. All 5 d orbitals have the same 3-D shape
Which of the statements best describes medical radioisotopes?
a. medical radioisotopes typically have relatively long half lives
b. medical radioisotopes typically have relatively short half lives
c. different radioisotopes are used to diagnose and treat a number of diseases
a. c only
b. b & c only
c. a & c only
d. b only
e. a only
b. b & c only
the heat of reaction is -196 kJ. Which of the follwoing statements is true about this reaction?
a. reaction is exothermic and heat is absorbed
b. reaction is exothermic and heat is released
c. reaction is endothermic and heat is absorbed
d. reaction is endothermic and heat is released
b. reaction is exothermic and heat is released
Which of the follwoign substances will produce the largest number of ions or molecules when dissolved in water?
a. 3 mole of C6H12O6
b. 1 mole K2SO4
c. 1 mole Al(NO3)3
d. 2 mole CH4O
c. 1 mole Al(NO3)3
What is the concentration of the aq OH- ion given that the concentration of the aq H3O+ ion is 1.5 x 10-5 M?
a. 1.0 x 10-7 M
b. 6.7 x 10-10 M
c. 1.5 x 109 M
d. 4.0 x 10-13 M
b. 6.7 x 10-10 M
A 20 g piece of metallic iron at room temp (25.0˚C) was exposed to 681 J of heat energy. What is the final temp of this metal? (SH of Fe = 0.452 J/ g ˚C)
a. 2.0 ˚C
b. 50.1 ˚C
c. 100.3 ˚C
d. 19.1 ˚C
c. 100.3 ˚C
A 120 mg sample of technetium-99 is used for a diagnostic test. If technetium-99 has a half-life of 6.0 h, how many mg of the technetium-99 sample remains active 24 h after the test?
a. 10. mg
b. 7.5 mg
c. 3.2 mg
d. 6.4 mg
b. 7.5 mg
Which are all the intermolecular forces exist between molecules of hydrogen bromide?
a. only dispersion
b. only dispersion, dipole-dipole and hydrogen bonding
c. only ion-dipole
d. only dispersion and dipole-dipole
d. only dispersion and dipole-dipole
An equilibrium mixture of SO2, O2 and SO3 at a certain temp contains 1.50 M SO2 and 0.0751 M O2. At this temp, Kc, equals 429 for this reaction:
2SO2 (g) + O2 (g) --> 2SO3 (g)
What is the equilibrium concentration of SO3?
a. 4.83 M
b. 0.735 M
c. 0.362 M
d. 0.851 M
d. 0.851 M
The pH of a solution is 5.00 at 25˚C. Which of the following is true about the solution?
a. [H3O+] is 1.0 x 10-9 M
b. [OH] is 1.0 x 10-5 M
c. solution is neutral
d. [H3O+] is 1.0 x 10-5 M
d. [H3O+] is 1.0 x 10-5 M