a. Elemental percent composition is the mass percent of each element in the compound.
The formula for mass elemental percent composition =
(1)
The molecular formula of cisplatin is
.
The atomic weight of the elements in cisplatin is:
Platinum, 
Nitrogen, 
Hydrogen, 
Chlorine, 
The molar mass of
=
= 
The mass of each element calculated using formula (1):
- Platinum,
%
%.
- Nitrogen,
%
%
- Hydrogen,
%
%
- Chlorine,
%
%
b. The given reaction of cisplatin is:

According to the balanced reaction, 1 mole of
gives 1 mole of
.
Now, calculating the number of moles of
in 100.0 g.
Number of moles = 
Molar mass of
= 
Number of moles of
=
.
Since, 1 mole of
gives 1 mole of
. Therefore, mass of cisplatin is:

For mass of
:
Molar mass of
= 
Since, 1 mole of
gives 2 mole of
. Therefore, mass of
is:

I can help, pm me and i will help you on there if that's alright?
The answer is C because you don’t have to worry about the number in front of the decimal unless it is something greater than zero. A- Doesn’t have there sig figs. B- The zero after the 5 doesn’t change it. D- The three at the end doesn’t matter because it does not round it up.
In order for you to calculate
for the mass of ammonium carbonate, you need to know the molar mass of it and
the nitrogen atoms in the compound. Ammonium carbonate has a molar mass of
96.08 grams per mole. There are two nitrogen atoms in ammonium carbonate which
is equal to 28.02 grams per mole. Divide the molar mass of nitrogen to the
ammonium carbonate, 28.02/96.08 x 100, we get 29.16wt% nitrogen.
It's an exciting and interesting process but those 5 points aren't worth a decent answer. The whole process is called fractioned distillation where different temperatures are reached, transforming the crude oil in gas. After being hit by a cold source it colds becoming different hydrocarbons depending on the temperatures.