Answer:
Part A
The volume of the gaseous product is 
Part B
The volume of the the engine’s gaseous exhaust is 
Explanation:
Part A
From the question we are told that
The temperature is 
The pressure is 
The of 
The chemical equation for this combustion is
The number of moles of 
that reacted is mathematically represented as
The molar mass of is constant value which is
So 
The gaseous product in the reaction is 
and water vapour
Now from the reaction
2 moles of will react with 25 moles of 
to give (16 + 18) moles of and 
So
1 mole of will react with 12.5 moles of to give 17 moles of and
This implies that
0.8754 moles of will react with (12.5 * 0.8754 ) moles of to give (17 * 0.8754) of and
So the no of moles of gaseous product is
From the ideal gas law
making V the subject
Where R is the gas constant with a value 
Substituting values
Part B
From the reaction the number of moles of oxygen that reacted is
The volume is
No this volume is the 21% oxygen that reacted the 79% of air that did not react are the engine gaseous exhaust and this can be mathematically evaluated as
Substituting values
An element is a pure substance that cannot be separated or divided into simpler substances by any method (physical or chemical). The four common elements in all the living organisms are carbon, oxygen, hydrogen, nitrogen.
Thus, the four elements that make up about 96 % of body matter are carbon, oxygen, hydrogen, nitrogen (c).
A is obviously out because it leads to a volume of 125.0 milliliters of the new solution and gives you a lower concentration than you were aiming for.
D is out because you are adding 75 milliliters of the stock solution, so your concentration would be too high. You only need 25.0 milometers of stock solution per 100 milliliters of the new solution.
C is also out because it leads to 50.0 milliliters stock solution per 100 milliliters of the new solution and hence the wrong concentration.
B is by default the correct answer. It also details the correct technique. First you add the stock solution (This you know from your calculations to be 25 milliliters.) then you add the water up to the volume you needed. (Because the calculations only tell you the total volume of water not what you need to add) You also add the water last so you can rinse the neck of the flask to make sure you also get all the stock solution residue into the stock solution.
I would add the final step of stirring, but B is the only answer that can be correct.
Some examples of malleable materials are gold, silver, iron, aluminum, copper and tin.
