Calculate the change in energy when 92.6 g sodium bicarbonate breaks down in the

Question

Calculate the change in energy when 92.6 g sodium bicarbonate breaks down in the following reaction: 2 NaHCO_3 (s) + 129 kJ rightarrow Na_2CO_3 (s) + H_2O (g) + CO_2 (g) Calculate the energy released when 24.8 g Na_2O reacts in the following reaction: Na_2O (s) + 2 HI (g) rightarrow 2 NaI (s) + H_2O (l) Delta H = -502.08 kJ The following equation shows the reaction that occurs when hydrogen peroxide decomposes: 2 H_2O_2 (l) rightarrow 2 H_2O(l) + O_2 (g) + 196.0 kJ a. Is this an endothermic or exothermic reaction? Why? b. Calculate the energy transfer involved in the decomposition of 250.0 mL of hydrogen peroxide (Density H O_2: = 1.4 g/mL).

Explanation / Answer

(4) Number o moles of nitroglyceerin used = 454 / 227.1 = 2.40 mol

From the balanced equation,

4 mol of nitro glycerin produces 7217.4 kJ of heat

then, 2.40 mol of nitroglycerin produces 7217.4 * 2.40 / 4 = 4330.44 kJ of heat

(5) moles of NaHCO3 = 92.6 / 84.01 = 1.102 mol

Form balanced equation provided,

2 mol of NaHCO3 absorbs 129 kJ of energy

then, 1.102 mol of NaHCo3 absorbs 1.102 * 129 /2 = 71.08 kJ of heat

(6) Moles of Na2O = 24.8 / 62 = 0.400 mol

From the balanced equation ,

1 mol of Na2O liberates 502.8 kJ of heat

then, 0.400 mol of Na2O produces 0.400 * 502.8 = 201.12 kJ of heat.

(7) (a) Since energy is released it is exothermic reaction

(b) mass of H2O2 = 1.4 * 250.0 = 350 g.

moles of H2O2 = 350 / 34 = 10.29 mol

from the balanced eqaution,

2 mol of H2O2 can produce 196.0 kJ of heat

then, 10.29 mol of H2O2 can produce 10.29 * 196.0 / 2 = 1008.42 kJ of heat

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.