SBVC CHEM 101 Dr. Lemieux
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.Name:______________________________________________
CHEMISTRY 101 Practice Exam #2 – 100 points
#1: Multiple Choice __________/ 60
#2: Free Response __________/ 40
TOTAL: __________/100
Instructions:
1. Cell phones must be put away and bags punt on the floor.
2. Once we begin the exam, you must ask Dr. Lemieux if you wish to leave and return. 3. Anyone caught cheating in any fashion will be disciplined, as indicated in the syllabus. 4. You will have 1 hr 15 min to complete this exam individually.
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intentionally
Page 3 Multiple Choice Section (3 points each, 60 points total)
1. Diatomic O2 can react with the element magnesium to form magnesium oxide (MgO). The balanced chemical equation is:
If 4 moles of magnesium totally reacted with more than enough O2, how many moles of MgO would be expected to form?
A) 1 mole B) 2 moles C) 4 moles D) 8 moles
E) not enough information
2. Which of the following statements is not a part of kinetic molecular theory? A) Matter is composed of particles that are in constant motion.
B) Particle velocity increases as the temperature decreases. C) Particles in a system can transfer energy to each other.
D) Particle interactions involve electrostatic attractions and repulsions.
3. A gas mixture contains each gas at the indicated partial pressure: N2 217 torr, O2 106 torr, He 248 torr. What is the total pressure of the mixture?
A) 382 torr B) 760 torr C) 571 torr
D) none of the above
4. Which among the following statements is TRUE?
A) The wavelength of light is inversely related to its energy. B) As the energy increases, the frequency of radiation decreases. C) As the wavelength increases, the frequency also increases. D) Red light has a shorter wavelength than violet light. E) none of the above
5. The boiling point of a liquid is
A) the temperature at which the rate of evaporation and sublimation are equal B) always 32.0ºC or greater
C) the temperature at which the pressure over the liquid equals the vapor pressure of the liquid
6. In which of the following pairs of state changes is the final state (solid, liquid, gas) the same for both members of the pair?
A) sublimation and evaporation B) condensation and freezing C) deposition and freezing
D) more than one correct response E) no correct response
7. Which of the following is not a factor in determining the magnitude of the vapor pressure of a liquid?
A) the temperature of the liquid
B) the strength of the attractive forces between molecules of the liquid C) the size of the container for the liquid
D) the type of forces between molecules within the liquid
8. Which form of electromagnetic radiation has the longest wavelength? A) Radio Waves
B) Microwaves C) X-rays D) Gamma Rays E) Infrared Radiation
9. How many moles are there in 82.5 grams of iron? A) 4.97 × 1025
B) 55.85 C) 0.677 D) 1.48
E) none of the above
10. Which of the following descriptions apply to matter in the solid state? A) solids have definite shape and high density
B) particles vibrate and do not move significantly
C) forces of motion in particles dominate over attractive forces D) more than one correct response
Page 5 11. What is the mass of a O.650 mol sample of Na?
A) 18.6 g B) 35.4 g C) 15.0 g D) 23.0 g
12. How many calories of energy are required to heat 150.0 g of coffee from 20.0 0C to 30.0 0C? Assume that the specific heat of coffee is 1.00 cal/g 0C like water.
A) 15.0 cal B) 150.0 cal C) 1.5 x 104 cal D) none of the above
13. Which of the following is a molecular compound that contains 5 moles of atoms per mole of the molecule?
A) germanium tetrafluoride B) dinitrogen monosulfide C) diarsenic pentasulfide D) silicon disulfide
14.Which of the following aqueous reactants would form an insoluble precipitate when reacting with aqueous sodium chloride:
A) potassium fluoride B) silver bromide C) calcium oxide D) iron (I) chloride
15. The formula mass of ammonium sulfite is A) 98.1 amu
B) 112.1 amu C) 116.14 amu D) 136.16 amu
16. In which of the following molar quantities of sulfur would 24
1.49 10 atoms of sulfur be present?
17. Which of the following samples contains the greatest number of atoms? A) 15 moles of CSe2
B) 16 moles of Ne C) 17 moles of N2O D) 18 moles of CS
18 An air sample is held in a closed container at pressure 1.0 atm at 27 0C. What is the pressure if the temperature is raised to 127 0C?[4 points]
A) 1.0 atm B) 1.3 atm C) 2.2 atm D) 4.7 atm
19. Which of the following is the correct "set-up" for the problem "How many grams of S are present in 74.9 g of S4N4?
A)
4 4
4 4
4 4 4 4
1 mole S N 4 moles S 32.07 g S
74.9 g S N × × ×
184.32 g S N 1 mole S N 4 moles S
B) 4 4 4 4
4 4 4 4
1 mole S N 4 moles S 32.07 g S
74.9 g S N × × ×
184.32 g S N 1 mole S N 1 mole S
C) 4 4 4 4
4 4 4 4
1 mole S N 1 moles S 32.07 g S
74.9 g S N × × ×
184.32 g S N 1 mole S N 1 mole S
D) 4 4 4 4
4 4 4 4
1 mole S N 1 mole S 32.07 g S
74.9 g S N × × ×
184.32 g S N 4 moles S N 1 mole S
20.The volume of a container containing gas at 8.0 atm pressure is decreased from 4.0 L to 2.0 L. What is the final pressure? [4 points]
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Name________________________ Student ID #__________________________
Free Answer Section (40 points total)
1. At constant pressure, the temperature of a 3.5 L sample of O2 at 20.0 0C is increased until the
temperature reaches 110.0 0C. What is the new volume in liters? (6 points)
2. What is the temperature of a 14.0 g sample of Ar in a 4.0L tank at 6.00 atm? (7 points)
3. What is the %O2 in a mixture of O2 and N2, with partial pressures 386 mmHg for oxygen and
4. Balance the following reaction and determine how many grams of MgO could be formed
using 15.7g of SiO2? (7 points)
____ Mg + ____ SiO2 ____ MgO + ____ Si
5. If the actual yield in the reaction above (question #4) was 2.42g of MgO, what is the percent
yield? (6 points)
6. How many kilojoules of energy are given off when 17.8 mol of CH4(g) is burned? (7 points) ___ CH4(g) + ___O2(g) → ___ CO2(g) + ___H2O(ℓ) ΔH = −890.1 kJ/mol
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Important Constants
1 atm = 760 mmHg = 760 torr R = 0.0821 (L*atm) / (mol * K)
1 mole gas has volume 22.4 L at STP (00C and 1 atm pressure)
K = 0C + 273.15
