Answer:
a) An exothermic reaction, will release heat. No heat will be absorbed.
b) 903.71 J of heat released
c) reaction is exothermic and ∆H will be negative.
d) ΔHreaction = 818.6 J/g
e) ΔHreaction = 45.6 kJ/mol
f) ΔHreaction = 91.2 kJ
Explanation:
<u>Step 1:</u> Data given
Mass of iron = 1.104 grams
Mass of hydrochloric acid = 26.023 grams
Initial temperature = 25.2°C
Final temperature = 33.5 °C
Temperature change = 8.3 °C
<u>Step 2:</u> The balanced equation
2Fe(s)+6HCl(aq) → 2FeCl3 (aq)+3H2 (g)
(A) Determine the amount of heat (in J) absorbed by the reaction mixture.
Since we have a rise of temperature, this means the reaction is exothermic.
An exothermic reaction, will release heat. No heat will be absorbed.
(B) How much heat (in J) was released by the reaction that occurred?
q = mC∆T
with q = heat released (in J)
with m = the mass (in grams)
with c = the specific heat capacity (in J/g°C)
with ∆T = The change in temperature (in °C)
q = (26.023g)*(4.184 J/g°C)*(8.3 °C) = 903.71 J of heat released
(C) Is this reaction exothermic or endothermic? Is ΔHreaction positive or negative?
Since we have a rise of temperature, this means the reaction is exothermic.
There is heat released so ∆H will be negative.
(D) Under constant pressure conditions (as used in this experiment), the heat released by the reaction equals the reaction enthalpy, qreleased = ΔHreaction. Determine ΔHreaction in Joules per gram of metal used (J/g).
ΔHreaction = 903.71 J/1.104 g = 818.6 J/g
(E) Determine ΔHreaction in kilojoules per mole of metal used (kJ/mol)
Number of moles of iron =1.104 grams / 55.845 g/mol = 0.0198 moles
ΔHreaction = 903.71 J / 0.0198 moles = 45641.9 J/mol = 45.6 kJ/mol
(F) Determine ΔHreaction in kilojoules per mole for the balanced reaction equation provided
Since we have 2moles of Fe in the balanced reaction;
ΔHreaction = 45.6 kJ/mol * 2 mol = 91.2 kJ
