Chemistry Test Key 2022

Exam Name___________________________________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A sample of gas (24.2 g) initially at 4.00 atm was compressed from 8.00 L to 2.00 L at constant temperature. After the compression, the gas pressure was __________ atm. D 4.00 A) 8.00 B) 16.0 C) 2.00 E) 1.00 1) 2) The pressure exerted by a column of liquid is equal to the product of the height of the column times the gravitational constant times the density of the liquid, P = ghd. How high a column of water (d = 1.0 g/mL) would be supported by a pressure that supports a 713 mm column of mercury (d = 13.6 g/mL)? A) 52 mm B) 9.7 × 103 mm C) 14 mm D 713 mm E) 1.2 × 104 mm 2) 3) Large intermolecular forces in a substance are manifested by __________. A) low vapor pressure B) high heats of fusion and vaporization C) high critical temperatures and pressures D high boiling point E) all of the above 3) 4) A sample of O 2 gas (2.0 mmol) effused through a pinhole in 5.0 s. It will take __________ s for the same amount of CO2 to effuse under the same conditions. D 3.6 A) 0.23 B) 5.9 C) 6.9 E) 4.3 4) 5) In which of the following molecules is hydrogen bonding likely to be the most significant component of the total intermolecular forces? A) CO2 B) CH3OH C) C5H 11OH D CH4 E)) C6H 13NH 2 5) 1 6) The heating curve shown was generated by measuring the heat flow and temperature of a solid as it was heated. The heat flow into the sample in the segment __________ will yield the value of the Hfusion of this substance. D DE A) AB B) BC C) CD E) EF 2 6) 7) Which one of the following substances will not have hydrogen bonding as one of its intermolecular forces? A) Answer 7) B) C) D ) E) 8) Arrange the following gases in order of increasing average molecular speed at 25°C. He, O 2, CO2, N2 A) He < O2 < N2 < CO 2 B) CO2 < N2 < O2 < He C) CO2 < He < N2 < O 2 D He < N2 < O2 < CO 2 E)) CO 2 < O 2 < N2 < He 3 8) 9) The shape of a liquid's meniscus is determined by __________. A) the volume of the liquid B) the amount of hydrogen bonding in the liquid C) the relative magnitudes of cohesive forces in the liquid and adhesive forces between the liquid and its container D the type of material the container is made of E) the viscosity of the liquid 9) 10) Of the following substances, only __________ has London dispersion forces as the only intermolecular force. D H2S A) NH 3 B) HCl C) CH3OH E) Kr ) 10) 11) Which statement is true about liquids but not true about solids? A) They flow and are compressible. B) They assume both the volume and the shape of their containers. C) They are highly ordered and not compressible. D They flow and are not compressible. E) They flow and are highly ordered. 11) 12) __________ are particularly polarizable. A) Small nonpolar molecules B) Small polar molecules C) Large polar molecules D Large nonpolar molecules E) Large molecules, regardless of their polarity, 12) ESSAY. Write your answer in the space provided or on a separate sheet of paper. 13) Acetylene gas C2H 2 can be prepared by the reaction of calcium carbide with water by the following reaction: CaC2 (s) + 2H2O (l) Ca(OH)2 (s) + C2H 2(g) Calculate the volume of C 2H2 that is collected over water at 23 o C by the reaction of 1.524g of CaC2 if the total pressure of gas is 753 torr. The vapor pressure of water at 23oC is 21.07torr. 4 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 14) Four identical 1.0-L flasks contain the gases He, Cl2, CH4, and NH3, each at 0°C and 1 atm pressure. Which gas sample has the greatest number of molecules? A) B) C) D E) 14) All the gases have the same number of molecules CH4 NH3 He Cl2 ESSAY. Write your answer in the space provided or on a separate sheet of paper. 15) How much heat is required to heat 55.0 g of ice at -10o C to become liquid water at +17 o C? In this temperature range, the specific heat of ice is 37.7 J/mol.K, and the specific of water is 75.8 J/mol.K. The molar heat of fusion of ice is 6.01 kJ/mol. 5 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 16) Standard temperature and pressure (STP), in the context of gases, refers to __________. A) 273 K and 1 torr B) 273 K and 1 pascal C) 298 K and 1 torr D 298 K and 1 atm E) 273 K and 1 atm 6 16)