Chemistry Reference
In-Depth Information
7.49
Calculate the percent chlorine in DDT, an
insecticide that has been discontinued because it does
not biodegrade.
C
14
H
9
Cl
5
,
7.69
(a) Calculate the number of moles of
C
2
H
4
in 44.7 g of
C
2
H
4
.
(b) Calculate the number of moles of carbon atoms in
44.7 g of
(c) Calculate the number of individual carbon atoms in
44.7 g of
C
2
H
4
.
7.50
Calculate the percent composition of niacin, a B-complex
vitamin,
C
6
H
5
NO
2
.
C
2
H
4
.
7.51
Calculate the percent composition of vitamin E,
C
29
H
50
O
2
.
7.70
Calculate the number of carbon atoms in 1.77 mol of
butene,
C
4
H
8
.
7.71
Calculate the number of hydrogen atoms in 1.11 mol of
acetaldehyde,
7.3 The Mole
C
2
H
4
O.
7.52
Calculate the formula mass and the molar mass of each
of the following compounds to three significant figures:
(a)
7.72
Calculate the number of grams of hydrogen in 4.11 mol
of ammonia.
(NH
4
)
2
CO
3
(b)
Ba(ClO
3
)
2
(c)
CaC
2
O
4
7.73
Calculate the mass of hydrogen in 6.92 g of
methane (natural gas).
CH
4
,
7.53
Calculate the number of grams of acetic acid,
in 1.76 mol of acetic acid.
HC
2
H
3
O
2
,
7.74
Calculate the number of grams of oxygen in 7.42 mol
of
7.54
Calculate the number of moles of butane,
C
4
H
10
,
in 151 g
Na
3
BO
3
.
of butane.
7.75
Calculate the number of hydrogen atoms in 41.4 g of
ethyl alcohol,
7.55
Calculate the mass of 1.25 mol of (a) unbonded oxygen
atoms, (b) oxygen atoms bonded into
C
2
H
6
O.
O
2
molecules,
7.76
Calculate the number of moles of
H
3
PO
4
that contains
and (c)
O
2
molecules.
10
24
6.78
oxygen atoms.
7.56
Calculate the number of moles of glucose, a simple
sugar,
7.77
Calculate the number of moles of ammonium chloride
that contains
C
6
H
12
O
6
,
in 283.5 g (10.00 oz).
10
24
1.37
hydrogen atoms.
7.57
Calculate the number of grams of acetaldehyde,
in 0.848 mol of acetaldehyde.
7.78
Calculate the mass of aluminum chloride that contains
chlorine atoms.
C
2
H
4
O,
2.22
10
23
7.58
Calculate the number of moles of methane (natural
gas),
7.79
Calculate the number of grams of oxygen in 1.63 mol
of
CH
4
,
in 175 g of methane.
Al(ClO
4
)
3
.
7.59
Calculate the number of moles in 12.9 g of a compound
with a molar mass of 62.0 g/mol.
7.80
Calculate the number of hydrogen atoms in 125 g of
benzene,
C
6
H
6
.
7.60
Calculate the number of moles in 1.93 g of a compound
with a molar mass of 98.0 g/mol.
7.81
Calculate the mass of
Cr(ClO
2
)
2
that contains
10
22
5.57
chlorine atoms.
7.61
Calculate the mass in grams of (a) one oxygen atom.
(b) one oxygen molecule.
7.82
Calculate the number of molecules of
C
5
H
12
containing
1.44
10
25
C
atoms.
7.62
Calculate the number of molecules in 12.9 g of a com-
pound with a molar mass of 64.0 g/mol.
10
23
7.83
Calculate the mass of N in
4.75
formula units
of
Mg
3
N
2
.
7.63
Calculate the mass of a sample of fruit sugar, fructose,
containing
7.84
Calculate the number of chlorine atoms in (a) 1.77 g of
and (b) 1.77 g of
2.65
10
20
C
6
H
12
O
6
,
molecules.
SCl
2
SOCl
2
.
7.64
Calculate the number of grams in 2.76 mol of ethyl al-
cohol,
C
2
H
5
OH.
7.4 Empirical Formulas
7.65
Calculate the number of molecules in 6.50 mol of
CH
4
.
7.85
Decide whether each of the following is an empirical
formula:
(a)
7.66
(a) Calculate the number of moles that contain
formula units of
(b) Calculate the number of molecules in 1.67 mol of
trinitrotoluene, TNT,
9.25
10
20
(NH
4
)
2
SO
4
.
C
2
H
8
N
2
(b)
K
2
S
2
O
8
(c)
Na
2
Cr
2
O
7
(d)
S
4
N
4
(e)
C
12
H
21
C
7
H
5
N
3
O
6
.
7.86
Decide whether each of the following is an empirical
formula:
(a)
7.67
Calculate the mass of a sample of table sugar, sucrose,
containing
1.91
10
24
C
12
H
22
O
11
,
molecules.
K
4
P
2
O
7
(b)
C
3
F
6
(c)
C
6
H
10
O
3
6.68
10
23
7.68
Calculate the mass of
molecules of PCl
3
.
(d)
Hg
2
Br
2
(e) H
2
C
2
O
4
