Transcript Document

pg 335
34. Determine the molar mass of each ionic compound.
a) NaOH
b) CaCl2
c) KC2H3O2
a)
1 mol Na*
22.99g Na
=22.99g Na
1 mol Na
1 mol O*
16.00g O
=16.00g O
1 mol O
1.008g H
=1.008g H
1 mol H
Molar mass=40.08 g/mol
b)
40.08g Ca = 40.08 g Ca
1 mol Ca*
1 mol Ca
1 mol H*
2 mol Cl*
35.45g Cl
1 mol Cl
=70.90 g Cl
Molar mass= 110.98 g/mol
c)
1 mol K* 39.10g K = 39.10g K
1 mol K
2 mol C* 12.01g C = 24.02 C
1 mol C
1.008g H
3 mol H* 1 mol H = 3.024g H
2 mol O*
16.00g O
1 mol O = 32.00 O
Molar mass= 98.14 g/mol
pg 335
35. Calculate the molar mass of each molecular
compound.
a) C2H5OH
b) HCN
c) CCl4
a) 2 𝑚𝑜𝑙 𝐶 𝑥
12.01 𝑔 𝐶
1 𝑚𝑜𝑙 𝐶
= 24.0 g/mol
1.008 𝑔 𝐻
6 𝑚𝑜𝑙 𝐻 𝑥
= 6.0 g/mol
1 𝑚𝑜𝑙 𝐻
16.00 𝑔 𝑂
= 16.0 g/mol
1 𝑚𝑜𝑙 𝑂 𝑥
1 𝑚𝑜𝑙 𝑂
Molar mass = 46.0 g/mol
c)
1 mol* 12.01g C =12.01 g C
1 mol C
4 mol Cl*
35.45g Cl
= 141.80 g Cl
1 mol Cl
Molar mass CCl4= 153.81 g/mol
b)
1 mol H*
1.008g H
=1.008g H
1 mol H
1 mol C* 12.01g C = 12.01g C
1 mol C
14.01g N
1 mol N*
= 14.01g
1 mol N
Molar mass HCl=27.03 g/mol
pg 336
37. The United States chemical industry produces
more sulfuric acid (H2SO4), in terms of mass, than
any other chemical. What is the mass of 3.25 mol of
H2SO4
1.008 𝑔 𝐻
= 2.016 𝑔 𝐻
2 𝑚𝑜𝑙 𝐻 𝑥
1 𝑚𝑜𝑙 𝐻
32.07 𝑔 𝑆
= 32.07 𝑔 𝑆
1 𝑚𝑜𝑙 𝑆 𝑥
1 𝑚𝑜𝑙 𝑆
16.00 𝑔 𝑂
4 𝑚𝑜𝑙 𝑂 𝑥
= 64.00 𝑔 𝑂
1 𝑚𝑜𝑙 𝑂
𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝐻2 𝑆𝑂4 = 98.09 𝑔/𝑚𝑜𝑙
98.09 𝑔 𝐻2 𝑆𝑂4
= 𝟑𝟏𝟗 𝒈 𝐻2 𝑆𝑂4
3.25 𝑚𝑜𝑙 𝐻2 𝑆𝑂4 𝑥
1 𝑚𝑜𝑙 𝐻2 𝑆𝑂4
pg 336
38. What is the mass of 4.35*10^-2 mol
of zinc chloride (ZnCl2).
65.38 𝑔 𝑍𝑛
1 𝑚𝑜𝑙 𝑍𝑛 𝑥
= 65.38 𝑔 𝑍𝑛
1 𝑚𝑜𝑙 𝑍𝑛
35.45 𝑔 𝐶𝑙 = 70.90 𝑔 𝐶𝑙
2 𝑚𝑜𝑙 𝐶𝑙 𝑥
1 𝑚𝑜𝑙 𝐶𝑙
𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑍𝑛𝐶𝑙2 = 136.28 𝑔/𝑚𝑜𝑙
4.35 𝑥
10−2 𝑚𝑜𝑙
𝑍𝑛𝐶𝑙2 𝑥
136.28 𝑔
1 𝑚𝑜𝑙 𝑍𝑛𝐶𝑙2
= 5.93 g 𝑍𝑛𝐶𝑙2
pg 337
40. Determine the number of moles present in
each compound.
= 0.133 mol
a) 22.6 g AgNO3 1 mole
169.9 g AgNO3
= 0.0403 mol
a) 6.50 g ZnSO4 1 mole
161.5 g ZnSO4
a) 35.0 g HCl
1 mole
36.5 g HCl
= 0.960 mol
pg 339
42. Ethanol (C2H5OH), a domestically produced fuel
source, is often blended with gasoline. A sample of
ethanol has a mass of 45.6g.
a) How many carbon atoms does the sample contain?
b) How many hydrogen atoms are present?
c) How many oxygen atoms are present
45.6 g 1 mol = .990 mol
46.07 g
a)
x
b)
x
c)
x
2 atoms C
1 molecule C2H5OH
6 atoms C
1 molecule C2H5OH
1 atom O
1 molecule C2H5OH
6.02*10^23
1 mol
= 1.19*1024 C atoms
= 3.59*1024 H atoms
= 5.96*1023 O atoms
pg 339
43. A sample of sodium sulfite (Na2SO3) has a mass of
2.25g.
a) How many Na+ ions are present?
b)How many SO3(2-) ions are present?
c) What is the mass in grams of one formula unit of
Na2So3
2.25 g Na2SO3 x 1 mol = 0.0178 mol
126.1 g
a)2.15*1022 Na+ ions
b)1.07*1022 So3 (2-) ions
c)2.09 * 10-22 g Na2So3/ formula unit
pg 339
44. A sample of carbon dioxide (CO2) has a mas of 52.0g.
a) How many carbon atoms are present?
b) How many oxygen atoms are present?
c) What is the mass in grams of one molecule of CO2?
52.0 g CO2 x 1 mol = 1.18 mol
44.0 g
a) x NA = 7.11*1023 C atoms
b) x NA x 2 = 1.42*1024 O atoms
c) 44.0 / NA = 7.31*10-23 g CO2/ molecule