Answer:
The correct answer is option A.
Explanation:
Initial volume of the gas =
Final volume of the gas = 
Initial pressure of the gas =
Final volume of the gas = 
Using Boyle's law:



Hence,the correct answer is option A.
It should be A)It lost a neutron.
Answer:

Explanation:
Given that:
The Half-life of
=
is less than that of 
Although we are not given any value about the present weight of
.
So, consider the present weight in the percentage of
to be y%
Then, the time elapsed to get the present weight of
= 
Therefore;

here;
= Number of radioactive atoms relating to the weight of y of 
Thus:

--- (1)
However, Suppose the time elapsed from the initial stage to arrive at the weight of the percentage of
to be = 
Then:
---- (2)
here;
= Number of radioactive atoms of
relating to 3.0 a/o weight
Now, equating equation (1) and (2) together, we have:

replacing the half-life of
=
( since
)
∴

The time elapsed signifies how long the isotopic abundance of 235U equal to 3.0 a/o
Thus, The time elapsed is 
Answers:
Human activities badly affect carbon cycle. Activities such as burning fossil fuel and deforestation have begun to effect on carbon cycle and the rise of carbon dioxide in atmosphere.
Explanation:
The carbon cycle can be affect when carbon dioxide is either released into atmosphere or remove from atmosphere. When fossil are burnt , carbon is release to the atmosphere at faster rate then it is removed. Natural gas, oil, coal, and other industrial products all are affecting carbon cycle in atmosphere.
Deforestation means permanent removal of trees from forest which cause increase in level of carbon dioxide because no trees longer to absorb carbon dioxide from atmosphere. Which result affect on carbon cycle.
Answer:
a) The relationship at equivalence is that 1 mole of phosphoric acid will need three moles of sodium hydroxide.
b) 0.0035 mole
c) 0.166 M
Explanation:
Phosphoric acid is tripotic because it has 3 acidic hydrogen atom surrounding it.
The equation of the reaction is expressed as:

1 mole 3 mole
The relationship at equivalence is that 1 mole of phosphoric acid will need three moles of sodium hydroxide.
b) if 10.00 mL of a phosphoric acid solution required the addition of 17.50 mL of a 0.200 M NaOH(aq) to reach the endpoint; Then the molarity of the solution is calculated as follows

10 ml 17.50 ml
(x) M 0.200 M
Molarity = 
= 0.0035 mole
c) What was the molar concentration of phosphoric acid in the original stock solution?
By stoichiometry, converting moles of NaOH to H₃PO₄; we have
= 
= 0.00166 mole of H₃PO₄
Using the molarity equation to determine the molar concentration of phosphoric acid in the original stock solution; we have:
Molar Concentration = 
Molar Concentration = 
Molar Concentration = 0.166 M
∴ the molar concentration of phosphoric acid in the original stock solution = 0.166 M