Answer:
(a) boiling point
(d) density at a given temperature and pressure.
Explanation:
Isomers are compounds that have the same molecular formula but different structural formulas. They differ in chemical and physical properties depending on the type of isomerism displayed by the compounds.
The compounds stated here are structural or constitutional isomers hence they possess different boiling points and densities at a given temperature and pressure owing to structural differences in the molecules.
Since they have the same molecular formula, they must yield the same result during combustion analysis and they must have the same molecular weight.
Star clusters is the only thing i can think of that would apply.
Magnesium in hydrochloric acid forms H2 (hydrogen) gas according to the balanced chemical equation:
Mg + 2HCl→H2 + MgCl2
I think it’s A but I’m not sure.
Answer:
ΔH =
Explanation:
In a calorimeter, when there is a complete combustion within the calorimeter, the heat given off in the combustion is used to raise the thermal energy of the water and the calorimeter.
The heat transfer is represented by
= 
where
= the internal heat gained by the whole calorimeter mass system, which is the water, as well as the calorimeter itself.
= the heat of combustion
Also, we know that the total heat change of the any system is
ΔH = ΔQ + ΔW
where
ΔH = the total heat absorbed by the system
ΔQ = the internal heat absorbed by the system which in this case is 
ΔW = work done on the system due to a change in volume. Since the volume of the calorimeter system does not change, then ΔW = 0
substituting into the heat change equation
ΔH =
+ 0
==> ΔH =