Quantitative Relationships in Chemistry
是非題
(1)
( ) The formula of a compound that expresses the smallest whole-number
ratio of the atoms present is called the molecular formula.
( ) 1 amu = 1.66 x 10-24 kg
( ) The mass percentage of a given element in a compound must always be
less than 100%.
( ) The reactant that is consumed first limits the amounts of products that
can form.
( ) The process of using a chemical equation to calculate the relative masses
(2)
(3)
(4)
(5)
of reactants and products involved in a reaction is called stoichiometry.
( ) The limiting reactant in a reaction is the reactant for which there is the
fewest number of moles.
(6)
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選擇題
(1)
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(2)
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(5)
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(7)
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Which of the following pairs of compounds have the same empirical
formula? (A) C2H6 and C4H10 (B) NO2 and N2O4 (C) C12H10O and
C6H5OH (D) H2SO4 and H2S2O8
1 amu = (A) 1.38 x 10-23 (B) 1.66 x 10-24 (C) 9.11 x 10-31 (D) 6.626 x
10-34 g
Which of the following has the highest mass percentage of nitrogen?
(A) NH3 (B) N2H4 (C) NO (D) NH4NO3
Which of the following has the largest percent by mass of carbon? (A)
CH4 (B) CH2O (C) CO (D) HCN
Avogadro’s number is 6.022 x (A) 1023 (B) 1024 (C ) 1025 (D) 1026.
The limiting reactant in a reaction is (A) the reactant for which there is
the least amount in grams (B) the reactant which has the lowest
coefficient in a balanced equation (C) the reactant for which there is
the fewest number of moles (D) none of the above
The process of using a chemical equation to calculate the relative
masses of reactants and products involved in a reaction is called (A)
balancing (B) quantization (C).stoichiometry (D) VSEPR.
2A + B → 3C + D
3.0 mol A and 2.0 mol B react to form 4.0 mol C. What is the percent
yield of this reaction? (A) 50 (B) 67 (C) 75 (D) 89 %
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問答或計算題
Symbol
H
C
Cl
N
O
Mg
Na
S
Si
V
Atomic 1.008 12.01 35.45 14.01 16.00 24.31 22.99 32.07 28.09 50.94
Mass
(1)
(2)
(a) Calculate the molar mass for Na2S2O3.
(b) Calculate the number of moles of sulfur atoms present in 2.01 g of
Na2S2O3.
A silicon chip has a mass of 5.68 mg. How many silicon (Si) atoms are present
(3)
in this chip?
(a) Calculate the molar mass for C7H14O2.
(4)
(5)
(6)
(7)
(8)
(b) Calculate the number of hydrogen atoms present in 1.0 g of C7H14O2.
A compound shows the following percent composition: 71.65% Cl, 24.27% C,
4.07% H.
The molar mass is known to be 98.96 g. Determine the empirical formula and
the molecular formula for this compound.
(a) Calculate the molar mass for carvone (C10H14O).
(b) Compute the mass percent of each element in carvone.
A very toxic sodium compound consists of 46.91% Na, 24.51% C, and 28.59%
N on a mass basis and has a molar mass of approximately 50 g/mol. Determine
the empirical and molecular formulas of the compound.
A compound with empirical formula CH was found by experiment to have a
molar mass of approximately 78 g, What is the molecular formula of the
compound?
Nylon-6 is 63.68% C, 12.38% N, 9.80% H, and 14.14% O. Calculate the
empirical formula for Nylon-6.
(9) When a 0.3546-g sample of vanadium metal is heated in air, it reacts with
oxygen to achieve a final mass of 0.6330 g. Calculate the empirical formula for
this vanadium oxide.
(10) 2 Mg(s) + O2(g) → 2 MgO(s)
How many grams of MgO(s) are produced by complete reaction of 1.25 g of
Mg?
(11) 2NH3(g) + 3CuO(g) → N2(g) + 3Cu(s) + 3H2O(l)
18.1 g of NH3 is reacted with 90.4 g of CuO.
(a) Which is the limiting reagent?
(b) What is the theoretical yield of N2?
(c) The reaction actually gave 6.63 g of N2, calculate the percent yield.
(12) 2H2(g) + CO(g) → CH3OH(l)
68.5 kg of CO is reacted with 8.60 kg of H2.
(a) Which is the limiting reagent?
(b) What is the theoretical yield of CH3OH?
(c) The reaction actually gave 35.7 kg of CH3OH, calculate the percent yield.
(1)
(a) 158.1 g/mol
(b) 0.0254 mol
(2)
1.22×1020 Si atms
(3)
(a) 130.18 g/mol
(b) 3.2×1016
(4)
Empirical formula: ClCH2
Molecular formula: Cl2C2H4
(5)
(a) 174.1 g/mol
(b) 68.98 % C, 3.474 % H, and 27.57 % O
(6)
Empirical formula: NaCN
Molecular formulas: NaCN
(7)
C6H6
(8)
C6NH11O
(9)
V2O5
(10) 2.07 g
(11) (a) CuO is the limiting reagent.
(b) 10.6 g
(c) 62.5%.
(12) (a) H2 is the limiting reagent.
(b) 6.86×104 g
(c) 52.0%