Chem 131 Exam 1 UPDATED
QUESTIONS AND CORRECT ANSWERS
Which of the following are combination reactions?
1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l)
2) CaO (s) + CO2 (g) → CaCO3 (s)
3) Mg (s) + O2(g) → MgO (s)
4) PbCO3 (s) → PbO (s) + CO2 (g) - CORRECT ANSWER 2 and 3
Of the following, only ________ is an extensive property. - CORRECT ANSWER volume
A small amount of salt, completely dissolved in water is an example of a ________ - CORRECT
ANSWER homogeneous mixture
A common English set of units for expressing velocity is miles/hour. The SI unit for velocity is
________. - CORRECT ANSWER m/s
Which one of the following molecular formulas is also an empirical formula?
A) H2O2
B) H2P4O6
C) C6H6
D) C2H6SO
E) C6H6O2 - CORRECT ANSWER D) C2H6SO
________ significant figures should be retained in the result of the following calculation.
(11.13-2.6)x(3.8x10^4)/
(103.05+16.9)x(1.2x10^-6) - CORRECT ANSWER 2
A compound contains 40.0% C, 6.71% H, and 53.29% O by mass. The molecular weight of the
compound is 60.05 amu. The molecular formula of this compound is ________. - CORRECT
ANSWER C2H4O2
QUESTIONS AND CORRECT ANSWERS
Which of the following are combination reactions?
1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l)
2) CaO (s) + CO2 (g) → CaCO3 (s)
3) Mg (s) + O2(g) → MgO (s)
4) PbCO3 (s) → PbO (s) + CO2 (g) - CORRECT ANSWER 2 and 3
Of the following, only ________ is an extensive property. - CORRECT ANSWER volume
A small amount of salt, completely dissolved in water is an example of a ________ - CORRECT
ANSWER homogeneous mixture
A common English set of units for expressing velocity is miles/hour. The SI unit for velocity is
________. - CORRECT ANSWER m/s
Which one of the following molecular formulas is also an empirical formula?
A) H2O2
B) H2P4O6
C) C6H6
D) C2H6SO
E) C6H6O2 - CORRECT ANSWER D) C2H6SO
________ significant figures should be retained in the result of the following calculation.
(11.13-2.6)x(3.8x10^4)/
(103.05+16.9)x(1.2x10^-6) - CORRECT ANSWER 2
A compound contains 40.0% C, 6.71% H, and 53.29% O by mass. The molecular weight of the
compound is 60.05 amu. The molecular formula of this compound is ________. - CORRECT
ANSWER C2H4O2
