Answer to Question #49936 in Inorganic Chemistry for Danny

Question

Question 1:

A compound A reacts according to the following hypothetical equation and has a molecular weight of 48.36 g/mol.

3 A (s) +B (aq) ––> 2 C (aq) ∆H° = ?

A sample of A, weighing 0.152 g reacts in a flask containing 250.00 g of water and the water temperature increases from 24.85 °C to a temperature of 26.26 °C. Calculate ∆H° for the reaction as written in the equation.

Answer: -1408 kJ

Question 2:

For which of the following reactions is ∆H° = ∆H°f, the heat of formation?
i. C (s) + 2 F2(g) ––> CF4 (g) ∆H° = – 221.0 kJ
ii. H(g) + Br (g) ––> HBr (g) ∆H° = –366.2 kJ
iii. 2 C(s) + H2(g) + 3 Cl2(g) ––> 2 CHCl3 (g) ∆H° = –268.2

Could you also explain exactly what Delta H means.