Answer:
The percent composition is 21% N, 6% H, 24% S and 49% O.
Explanation:
1st) The molar mass of (NH4)2SO4 is 132g/mol, and it represents the 100% of the mass composition.
In 1 mole of (NH4)2SO4, there are:
- 2 moles of N.
- 8 moles of H.
- 1 mole of S.
- 4 moles of O.
2nd) It is necessary to calculate the mass of each element, multiplying its molar mass by the number of moles:
- 2 moles of N (14g/mol) = 28g
- 8 moles of H (1g/mol) = 8g
- 1 mole of S (32g/mol) = 32g
- 4 moles of O (16g/mol) = 64g
3rd) With a mathematical rule of three we can calculate the percent composition of each element in the molecule of (NH4)2SO4:




In this case, we can calculate the percent composition of Oxygen by subtracting the other percentages, since the total must be 100%.
So, the percent composition is 21% N, 6% H, 24% S and 49% O.
It means it’s neutrally charged! Protons are positive while electrons are negative, so they balance each other out. Neutrons are neutral so they don’t weigh in.
Answer : The value of
for this reaction is 36.18 kJ
Explanation :
First law of thermodynamic : It states that the energy can not be created or destroyed, it can only change or transfer from one state to another state.
As per first law of thermodynamic,

where,
= internal energy of the system
q = heat added or rejected by the system
w = work done
As we are given that:
q = 38.65 kJ
w = -2.47 kJ (system work done on surrounding)
Now put all the given values in the above expression, we get:


Therefore, the value of
for this reaction is 36.18 kJ