Option d: copper.
Because copper is an element, not a mixture.
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 × ![\frac{1 mole (dimethylphthalate)}{194.184g(dimethylphthalate)}](https://tex.z-dn.net/?f=%5Cfrac%7B1%20mole%20%28dimethylphthalate%29%7D%7B194.184g%28dimethylphthalate%29%7D)
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 =
![(T_f-T_i} )](https://tex.z-dn.net/?f=%28T_f-T_i%7D%20%29)
21.84 kJ =6.15 kJ/°C ![* (T_f-21,5^0C)](https://tex.z-dn.net/?f=%2A%20%28T_f-21%2C5%5E0C%29)
21.84 KJ = ![(6.15 kJ/^0C * T_f) - (6.15 kJ/^0C*21.5^0C)](https://tex.z-dn.net/?f=%286.15%20kJ%2F%5E0C%20%2A%20T_f%29%20-%20%286.15%20kJ%2F%5E0C%2A21.5%5E0C%29)
21.84 KJ =
- 132.225 kJ
21.84 KJ + 132.225 kJ = ![(6.15 kJ/^0C * T_f)](https://tex.z-dn.net/?f=%286.15%20kJ%2F%5E0C%20%2A%20T_f%29)
154.065 kJ = ![(6.15 kJ/^0C * T_f)](https://tex.z-dn.net/?f=%286.15%20kJ%2F%5E0C%20%2A%20T_f%29)
= ![\frac{154.065kJ}{6.15kJ/^0C}](https://tex.z-dn.net/?f=%5Cfrac%7B154.065kJ%7D%7B6.15kJ%2F%5E0C%7D)
=25.05°C