<span>Answer:
Enthalpy is delta-H-
We need to look at the molecule and determine which bonds are broken adn which bonds are formed.
Bonds that are broken are H-H (from the H2 molecule) and the C=O from acetone.
their energies add up like this: 436 kJ + 745 kJ = 1181 kJ
looking at the bonds formed, these are C-O, O-H, and C-H. these add up to 1229 kJ
solving for delta H by taking the sum of the broken bonds and subtracting the sum of the formed bonds, like so:
1181 - 1229 = -48 kJ</span>
Answer:

Explanation:
Assume the reaction is the combustion of propane.
Word equation: propane plus oxygen produces carbon dioxide and water
Chemical eqn: C₃H₈(g) + O₂(g) ⟶ CO₂(g) + H₂O(g)
Balanced eqn: C₃H₈(g) + 5O₂(g) ⟶ 3CO₂(g) + 4H₂O(g)
(a) Table of enthalpies of formation of reactants and products

(b)Total enthalpies of reactants and products

ΔᵣH° is negative, so the reaction is exothermic.
It wont melt like gold and copper would at that temperature
Mercury (ii) oxide is made up of mercury and oxygen. The total mass of mercury (ii) oxide is 14.2 g, after decomposition 13.2 g of mercury were formed, therefore the mass of oxygen 1 g (14.2 g -13.2 g).
Percentage of oxygen = (1/14.2)×100 = 7.04%
Percentage of mercury = (13.2/14.2) × 100 = 92.96%
Therefore, percentage composition of the compound, oxygen is 7.04% and mercury is 92.96%.
Answer:
D.
Double replacement, CaO + Cl2O
Explanation: