I think it's D, because theoretical yield is like, the yield you'd get if 100% of the reactants formed to make product. Well that's how I think of it, but it has something to do with limiting reagents and stuff. Sorry this isn't a really detailed explanation.
Answer:
All atoms of the same element have always have the same amount of protons.
Explanation:
Atoms of the same element have always have the same amount of protons but not always the same electrons and neutrons. If an atom gains or loses one of its valance electrons, the electrons on the outermost shell, then it becomes ionized. Also not all atoms of the same element have the same amount of neutron. This is called an isotope. A good example would be Carbon 13. Normally, Carbon atoms have an atomic mass of 12 AMU or 12 atomic mass units. However, Carbon atoms have an atomic mass of 13 AMU, consisting of 7 neutrons instead of 6 neutrons. So the only thing that all atoms of the same element have in common is the amount of protons.
Answer: Th enthalpy of combustion for the given reaction is 594.244 kJ/mol
Explanation: Enthalpy of combustion is defined as the decomposition of a substance in the presence of oxygen gas.
W are given a chemical reaction:
To calculate the enthalpy change, we use the formula:
This is the amount of energy released when 0.1326 grams of sample was burned.
So, energy released when 1 gram of sample was burned is = 
Energy 1 mole of magnesium is being combusted, so to calculate the energy released when 1 mole of magnesium ( that is 24 g/mol of magnesium) is being combusted will be:
Given the percentage composition of HC as C → 81.82 % and H → 18.18 %
So the ratio of number if atoms of C and H in its molecule can will be:
C : H = 81.82 12 : 18.18 1 C : H = 6.82 : 18.18 = 6.82 6.82 : 18.18 6.82 = 1 : 2.66 ≈ 3 : 8
So the Empirical Formula of hydrocarbon is:
C 3 H 8
As the mass of one litre of hydrocarbon is same as that of C O 2 The molar mass of the HC will be same as that of C O 2 i.e 44 g mol
Now let Molecular formula of the HC be ( C 3 H 8 ) n
Using molar mass of C and H the molar mass of the HC from its molecular formula is:
( 3 × 12 + 8 × 1 ) n = 44 n So 44 n = 44 ⇒ n = 1
Hence the molecular formula of HC is C 3 H 8
Does that help?
