Answer:
Single molecule of methane (\[C{{H}_{4}}\]) contains 10
electrons
\[\therefore \] Number of electrons in 1 mole of \[C{{H}_{4}}\]
\[=6.023\times {{10}^{23}}\times
10\]
\[=6.023\times {{10}^{24}}\]
\[\therefore \] 1 mole of methane contains \[6.023\times
{{10}^{24}}\] electrons.
(ii) Find (a) the total number and (b) total
mass of neutrons in 7 mg of \[_{6}^{14}C\] (Assume that mass of neutron \[=1.675\times
{{10}^{-27}}kg)\]
Sol: Total number of carbon atom
\[=\frac{W}{Atomic\,Weight}\times
6.022\times {{10}^{23}}\]
\[=\frac{7\times
{{10}^{-3}}}{14}\times 6.022\times {{10}^{23}}=3.011\times {{10}^{20}}\]
(a) Each atom of \[_{6}^{14}C\] contains
8 neutrons
\[\therefore \]Total number of
neutrons in given sample
\[=3.011\times {{10}^{20}}\times
8\]
\[=2.4088\times {{10}^{21}}\]
(b) Mass of total neutrons
\[=2.4088\times
{{10}^{21}}\times 1.675\times {{10}^{-27}}kg\]
\[=4.0347\times {{10}^{-6}}kg\]
(iii) Find (a) total number (b) the
total mass of protons in 34 mg of \[N{{H}_{3}}\] at STP. Will the answer change
if the temperature and pressure are changed?
Sol: Number of molecules of
\[\text{N}{{\text{H}}_{\text{3}}}\frac{\text{Mass}}{\text{Atomic}\,\text{mass}}\text{
}\!\!\times\!\!\text{ Avogadro }\!\!'\!\!\text{
s}\,\text{number}\]\[=\frac{(34\times {{10}^{-3}})}{17}\times 6.023\times
{{10}^{23}}\]
\[=1.2046\times {{10}^{21}}\]
Each molecule of ammonia (\[N{{H}_{3}}\])
contains ten protons
\[\therefore \] Total number of
protons = \[1.2046\times {{10}^{21}}\times 10\]
\[=1.2046\times {{10}^{22}}\]
Mass of protons = Number of
protons x Mass of one proton
\[=1.2046\times {{10}^{22}}\times
1.672\times {{10}^{-24}}g\]
\[=0.0201g\]
Answer will not change with temperature and pressure because
mass of ammonia will remain the same.
You need to login to perform this action.
You will be redirected in
3 sec
