The Periodic Table
1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Atomic number
1
H
1.01
2
He
4.00
Element
4
Be
9.01
3
11
Na
22.99
12
Mg
24.31
4
19
K
39.10
20
Ca
40.08
21
Sc
44.96
22
Ti
47.87
23
V
50.94
24
Cr
52.00
25
Mn
54.94
5
37
Rb
85.47
38
Sr
87.62
39
Y
88.91
40
Zr
91.22
41
Nb
92.91
42
Mo
95.96
43
Tc
(98)
6
56
57 †
72
55
Ba
La
Cs
Hf
132.91 137.33 138.91 178.49
73
Ta
180.95
74
W
183.84
7
87
Fr
(223)
104
Rf
(267)
105
Db
(268)
106
Sg
(269)
107
Bh
(270)
58
Ce
140.12
59
Pr
140.91
60
Nd
144.24
61
Pm
(145)
90
Th
232.04
91
Pa
231.04
92
U
238.03
93
Np
(237)
Relative atomic mass
89 ‡
Ac
(227)
†
‡
26
Fe
55.85
27
Co
58.93
28
Ni
58.69
29
Cu
63.55
30
Zn
65.38
5
B
10.81
6
C
12.01
7
N
14.01
8
O
16.00
9
F
19.00
10
Ne
20.18
13
Al
26.98
14
Si
28.09
15
P
30.97
16
S
32.07
17
Cl
35.45
18
Ar
39.95
31
Ga
69.72
32
Ge
72.63
33
As
74.92
34
Se
78.96
35
Br
79.90
36
Kr
83.90
45
48
54
50
46
44
49
51
47
52
53
In
I
Rh
Cd
Xe
Sn
Pd
Ru
Sb
Ag
Te
101.07 102.91 106.42 107.87 112.41 114.82 118.71 121.76 127.60 126.90 131.29
75
80
78
76
81
79
77
Re
Pt
Os
Tl
Au
Ir
Hg
186.21 190.23 192.22 195.08 196.97 200.59 204.38
108
Hs
(269)
109
Mt
(278)
110
Ds
(281)
111
Rg
(281)
112
Cn
(285)
113
Unt
(286)
82
Pb
207.2
83
Bi
208.98
84
Po
(209)
85
At
(210)
86
Rn
(222)
114
Uug
(289)
115
Uup
(288)
116
Uuh
(293)
117
Uus
(294)
118
Uuo
(294)
66
68
64
62
67
69
65
63
70
71
Dy
Sm
Tm
Tb
Lu
Er
Gd
Ho
Eu
Yb
150.36 151.96 157.25 158.93 162.50 164.93 167.26 168.93 173.05 174.97
94
Pu
(244)
95
Am
(243)
96
Cm
(247)
97
Bk
(247)
98
Cf
(251)
99
Es
(252)
100
Fm
(257)
101
Md
(258)
102
No
(259)
103
Lr
(262)
N19/4/CHEMI/HPM/ENG/TZ0/XX
3
Li
6.94
–2–
2
88
Ra
(226)
18
Ionic formulae
The other type of formulae you need to be able to write are those of ionic
compounds. Compounds made up of positive cations and negative anions.
To write these you need to know or have access to a table of ions.
Table of Ions for Yr10 Chemistry
Cations (metal ions)
1±
H±
2±
hydrogen
3±
Mg2+ magnesium
Al‹± aluminium
Na± sodium
Ca2+ calcium
Fe‹± iron(III)
K± potassium
Ba2+ barium
NH¢± ammonium
Fe2+ iron(II)
Ag± silver
Cu2+ copper
Li± lithium
Zn2+ zinc
Sn2+ tin
Pb2+ lead
Note other names, Fe"± ferrous, Fe‹± ferric, Cu"± cupric.
Anions (non-metal ions)
1—
2—
3—
OH— hydroxide
O2- oxide
PO¢‹— phosphate
F— fluoride
S2- sulphide
N‹— nitride
Cl— chloride
CO£2- carbonate
P‹— phosphide
Br— bromide
SO¢2- sulphate
I— iodide
SO£2- sulphite
NO£— nitrate
HCO£— hydrogencarbonate
CH£COO— ethanoate
Yr 10 booklet 2013, page 42
Name______________________________________
3.
0.487 g sample of quinine 324g/mol is combusted and found to produce 1.321 g carbon
dioxide 0.325 g water and 0.0421 g nitrogen. Determine in empirical and molecular formula
(hint there is one element missing!)
4. After combustion with excess oxygen, a 12.501 g of a petroleum compound produced
38.130 g of carbon dioxide and 18.732 of water. A previous analysis determined that the
compound does not contain oxygen. Establish the empirical formula of the compound
5. A hydrocarbon fuel is fully combusted with 22.000 g of oxygen to yield 23.118 g of carbon
dioxide and 4.729 g of water. Find the empirical formula for the hydrocarbon.
6. 12.915 g of a biochemical substance was burned in an atmosphere of 50.123 g of oxygen.
Subsequent analysis of the gaseous result yielded 18.942 g carbon dioxide, 7.749 g of water
and 36.347 g of oxygen. Determine the empirical formula of the substance.
7. A 12.00 gram sample of a smelly compound was tested by combustion analysis. The
products were 21.41 grams of CO2, 14.59 grams of H2O, and 17.51 grams of N2O5. Further
analysis showed that oxygen was NOT present in the molecule. What is the empirical
formula of the compound?
8. When a 10.0 g sample of an unknown organic acid is subjected to combustion analysis 21.2
grams of CO2 and 3.25 g of H2O are produced. What is the empirical formula of the acid?
Answers:
3. C10H12NO, C20H24N2O2
4. C5H12 when I re-did the answer, I noticed that the ratio was off. The answer is not C3H7
5. CH, there is no oxygen in the compound and the amount of oxygen reacted is excess.
6. CH2O, oxygen is in excess. You can’t use it to find the amount of oxygen in the compound.
7. C3H10N
8. C4H3O2
Empirical formula and combustion analysis worksheet
Page 8 of 8
3/4/18
–3–
1.
2.
M10/4/CHEMI/HPM/ENG/TZ2/XX+
What is the mass, in g, of one molecule of ethane, C2H6?
A.
3.0 10
23
B.
5.0 10
23
C.
30
D.
1.8 1025
6.0 mol of aluminium reacts with oxygen to form aluminium oxide. What is the amount of oxygen,
in mol, needed for complete reaction?
4Al (s) + 3O2 (g) → 2Al2O3 (s)
3.
A.
1.5
B.
3.0
C.
4.5
D.
6.0
Which of the following is consistent with Avogadro’s law?
A.
B.
4.
P
T
V
T
C.
Vn
D.
V
n
constant (V, n constant)
constant (P, n constant)
constant (P, T constant)
constant (P, T constant)
A sample of element X contains 69 % of 63X and 31 % of 65X. What is the relative atomic mass of X
in this sample?
A.
63.0
B.
63.6
C.
65.0
D.
69.0
2210-6113
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