Chemistry Reference
In-Depth Information
EXAMPLE 21.18
When a positron and an electron meet, the matter in both is totally converted
to energy. (They annihilate each other.) The mass of each of these particles is
Calculate the number of joules of energy released in each
annihilation reaction
10
31
kg.
9.10
1 kg
#
m
2
/s
2
).
(1 J
Solution
The total mass of a positron and an electron involved in the annihilation reaction
is
10
31
kg)
10
31
kg)
10
30
kg.
(9.10
(9.10
1.820
The energy is
given by Einstein's equation:
mc
2
10
30
kg) (3.00
10
8
m/s)
2
E
(1.820
10
13
J
1.64
Snapshot Review
❒
Combination of smaller nuclei into larger ones is called nuclear
fusion. The reactions of the Sun and stars are fusion reactions.
A. Complete the following equation:
1
1
1
H £
1
H
1
H
?
Key Terms
Key terms are defined in the Glossary.
alpha particle (21.1)
atomic bomb (21.3)
beta particle (21.1)
chain reaction (21.3)
control rod (21.3)
critical mass (21.3)
daughter isotope (21.1)
deuterium (21.4)
deuteron (21.4)
disintegration (21.1)
Einstein's equation (21.3)
electromagnetic radiation (21.1)
event (21.1)
gamma particle (21.1)
Geiger counter (21.1)
half-life (21.2)
hydrogen bomb (21.4)
isotopes (21.1)
nuclear fission (21.3)
nuclear fusion (21.4)
nuclear radiation (21.1)
parent isotope (21.1)
particle accelerator (21.3)
positron (21.3)
radioactive dating (21.2)
radioactive decay (21.1)
radioactive series (21.1)
radioactivity (21.1)
tracer (21.1)
transmutation (21.3)
tritium (21.4)
Symbols
a
(alpha particle) (21.1)
(beta particle) (21.1)
or (positron) (21.3)
d (deuteron) (21.4)
g
(gamma particle) (21.1)
n (neutron) (21.3)
N
(number of nuclei) (21.2)
(original number of nuclei) (21.2)
p (proton) (21.3)
(half-life) (21.2)
N
o
b
0
0
b
1
b
t
1/2
