Answer:
A) Exothermic
B) (1) -410.5 kJ (2) -98.1 kcal
C) -976.44 kJ
Explanation:
A) By the value of ΔH (-1236 kJ), we can see that it's negative, it means that the heat is being lost by the reaction, and, because of that, the reaction is exothermic.
B) The molar mass of ethanol is 46.07 g/mol, so, at 15.3 grams, the number of moles is:
n = mass/molar mass
n = 15.3/46.07
n = 0.3321 mol
By the equation
1 mol of ethanol ----------------------- -1236 kJ
0.3321 mol of ethanol ----------------------- x
By a simple direct three rule:
x = -410.5 kJ
1 kJ --------------- 0.2390 kcal
-410 kJ ---------- y
y = -98.10 kcal
C) The molar mass of water is 18 g/mol, so the number of moles at 42.7 g is:
n = 42.7/18
n = 2.37 moles
By the equation
3 moles of water ----------------------- -1236 kJ
2.37 moles of water --------------------- x
By a simple direct three rule:
3x = -2929.32
x = -976.44 kJ
