Answer:
= 25.05°C
Explanation:
Given:
the value of ΔHcomb (heat of combustion) for dimethylphthalate (C10H10O4) is = 4685 kJ/mol.
mass = 0.905g of dimethylphthalate
molar mass = 194.18g dimethylphthalate
number of moles of dimethylphthalate = ???
= 21.5°C
= 6.15 kJ/°C
= ???
since we have our molar mass and mass of dimethylphthalate ;we can determine the number of moles as;
0.905g of dimethylphthalate × 
number of moles of dimethylphthalate = 0.000466 moles
Heat released = moles of dimethylphthalate × heat of combustion
= 0.000466 moles × 4685 kJ
= 21.84 kJ
∴ Heat absorbed by the calorimeter =

21.84 kJ =6.15 kJ/°C 
21.84 KJ = 
21.84 KJ =
- 132.225 kJ
21.84 KJ + 132.225 kJ = 
154.065 kJ = 
= 
=25.05°C
True. Covalent bonds involve sharing electrons to create a full valence shell.
Answer:
Explanation:
We can only talk about resonance hybrid for a compound in which more than one structure is possible based on its observed chemical properties.
There are compounds whose chemical properties can not be satisfactorily explained on the basis of a single chemical structure. In the case of such compounds, we invoke the idea of resonance.
A resonance hybrid is a single structure drawn to represent a given chemical specie which exhibits resonance behaviour and can otherwise be represented on paper in the form of an average of two or more chemical structures separated each from the next by a double-headed arrow.