90年上 周必泰 普通化學甲上期中考part B
B-4 單選題 (3%*20=60%)
1.The empirical formula of sugar is CH2O and its molar mass is 180.2g /mole. If
one teaspoom of sugar weighs 3.50grams, how many moles and molecules of
sugar are present?
2.A solution contains the ions Ag+, Pb2+, and Ni2+. Dilute solutions of NaCl,
Na2SO4,and Na2S are available to separate the positive ions from each other
. To separate the ions, in which order should the solytions be added?
a)Na2SO4, NaCl, Na2S
b)Na2SO4, Na2S, NaCl
c)Na2S, NaCl, Na2SO4
d)NaCl, Na2S, Na2SO4
e)NaCl, Na2SO4, Na2S
3.Which of the following statements is true for ideal gases?
a)The temperature of the gas sample is directly related to the average
velocity of the gas particles.
b)At STP, 1.0L of Ar(g) contains about twice the number of atoms as 1.0L of
Ne(g) because the molar mass of Ar is about twice that of Ne.
c)A gas exerts pressure because its molecules collide with the walls of the
container to release the energy.
d)The gas particles in a sample attract each other.
e)None of the above.
4.Which element does not belong to the family or classification indicated?
b)He, noble gas
c)Fe, transition metal
d)K, alkali metal
5.Identify the strongest base.
6.Iron(II) sulfate reacts with potassium hydroxide in aqueous solution to form
a precipitate. What is the net ionic equation for this reaction?
a)Fe2+(aq) + SO4 2-(aq) → FeSO2(s)
b)2K+(aq) + SO4 2-(aq) → K2SO4(s)
c)2Fe3+(aq) + 3SO4 2-(aq) → Fe2(SO4)3(s)
d)Fe2+(aq) + 2OH-(aq) → Fe(OH)2(s)
e)K+(aq) + Fe2+(aq) → Fe3+(aq)
7.According to the equation 2KClO3(s) → 2KCl(s) + O2(g)
3.00-g sample of KClO3 decomposes and the oxygen at 24.0度C and 0.982atm is
collected. What volume of oxygen gas will be collected, assuming 100% yield
? Atomic mass, K:39, Cl:35
e)none of these
8.An aqueous solution of barium nitrate reacts with an aqueous solution of
sodium sulfate. Identify the solid and indicate its coefficient in the
e)None of these
9.The Claus reactions, shown below, are used to generate elemental sulfur from
hydrogen sulfide. (atomic mass:S=32)
H2S + O2 → SO2 + H2O (unbalanced)
SO2 + H2S → S + H2O (unbalanced)
How much sulfur(in grams) is produced from 48.0grams of O2?
a) 16.0g , b) 32.1g , c) 48.1g , d) 96.2g , e)none of those
10.Which of the following is true?
a) O and F have the same number of neutrons.
b) C and N are isotopes of each other because their mass numbers are the
18 2- 20
c) O has different number of electrons as Ne.
d)The radius of a nucleus is ~ 10^ -8 cm
e)None of the above