1、When the following equation is balanced, the coefficients are __________. NH3 (g) + O2 (g) → NO2 (g) + H2O (g)
A、4, 7, 4, 6
B、2, 3, 2, 3
C、4, 3, 4, 3
D、1, 1, 1, 1
E、1, 3, 1, 2
2、When the following equation is balanced, the coefficient of Al is __________. Al (s) + H2O (l) → Al(OH)3 (s) + H2 (g)
A、3
B、4
C、5
D、2
E、1
3、When the following equation is balanced, the coefficient of O2 is __________. C2H4O (g) + O2 (g) → CO2 (g) + H2O (g)
A、2
B、1
C、3
D、5
E、4
4、Write the balanced equation for the reaction that occurs when methanol, CH3CH (l) is burned in air. What is the coefficient of methanol in the balanced equation?
A、3
B、2
C、1
D、4
E、1.5
5、The balanced equation for the decomposition of sodium azide is __________.
A、2NaN3 (s) → 2Na (s) + 2N2 (g)
B、2NaN3 (s) → 2Na (s) + 3N2 (g)
C、NaN3 (s) → Na (s) + N2 (g) + N (g)
D、2NaN3 (s) → Na2 (s) + 3N2 (g)
E、NaN3 (s) → Na (s) + N2 (g)
6、The solubility of manganese (II) hydroxide (Mn(OH)2) is 2.2 × 10-5 M. What is the Ksp of Mn(OH)2?
A、4.8 × 10-10
B、2.2 × 10-5
C、4.3 × 10-14
D、2.1 × 10-14
E、1.1 × 10-14
7、What is the empirical formula of a compound that contains 49.4 % K, 20.3 % S, and 30.3 % O by mass?
A、KSO3
B、K2SO3
C、KSO4
D、KSO2
E、K2SO4
8、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 __________.
A、C2H2O4
B、CHO2
C、C2H4O2
D、CH2O
E、C2H3O4
9、Magnesium and nitrogen react in a combination reaction to produce magnesium nitride: 3 Mg + N2 → Mg3N2 In a particular experiment, a 9.27 g sample of N2 reacts completely. The mass of Mg consumed is __________ g.
A、16.1
B、0.92
C、24.1
D、13.9
E、8.04
10、Which of the following reactions is a redox reaction? (a) K2CrO4 + BaCl2 → BaCrO4 + 2KCl (b) Pb22+ + 2Br- → PbBr (c) Cu + S → CuS
A、(b) and (c)
B、(a) and (c)
C、(a) only
D、(b) only
E、(c) only
