Answer : The partial pressure of
and
are, 84 torr and 778 torr respectively.
Explanation : Given,
Mass of
= 15.0 g
Mass of
= 22.6 g
Molar mass of
= 197.4 g/mole
Molar mass of
= 32 g/mole
First we have to calculate the moles of
and
.

and,

Now we have to calculate the mole fraction of
and
.

and,

Now we have to partial pressure of
and
.
According to the Raoult's law,

where,
= partial pressure of gas
= total pressure of gas
= mole fraction of gas


and,


Therefore, the partial pressure of
and
are, 84 torr and 778 torr respectively.
Answer:
Half life = 1600 years
Explanation:
Given data:
Total mass of sample = 45.00 g
Mass remain = 5.625 g
Time period = 4800 years
Half life of radium-226 = ?
Solution:
First of all we will calculate the number of half lives passes,
At time zero 45.00 g
At first half life = 45.00 g/ 2= 22.5 g
At 2nd half life = 22.5 g/ 2 = 11.25 g
At 3rd half life = 11.25 g/ 2= 5.625 g
Half life:
Half life = Time elapsed / number of half lives
Half life = 4800 years / 3
Half life = 1600 years
Answer:
Age of rock = 722 million years old
Explanation:
Using the formula; <em>fraction remaining = 0.5ⁿ</em>
where n = number of half lives elapsed.
However, from the given values, fraction remaining = 1.000 - 0.0105
fraction remaining = 0.9895
Substituting in the formula to determine the number of half-lives:
0.9895 = 0.5ⁿ
log 0.9895 = n log 0.5
-0.0045842 = -0.30103 n
number of half lives elapsed, n = 0.0152
Therefore age of rock = 0.0152 x 4.75 x 10¹⁰ years = 7.22 x10⁸ years
Age of rock = 722 million years old