3. Matter and Energy

Is the total enthalpy (H) of the reactants for an endothermic reaction greater than or less than the total enthalpy of the products?

Classify each of the following as exothermic or endothermic: c. The metabolism of glucose in the body provides energy.

Hydrogen chloride can be made from the reaction of chlorine and hydrogen: Cl2(g) + H2(g) → 2 HCl(g) For this reaction, K = 26 x 10^33 and ∆H = -44 kcal/mol(-184 kJ/mol) at 25 °C. Is the reaction endothermic or exothermic?

The vaporization of Br2 from the liquid to the gas state requires 7.4 kcal/mol (31.0 kJ/mol). What is the sign of ∆H for this process? Write a reaction showing heat as a product or reactant.

Classify each of the following as exothermic or endothermic: b. In the body, the synthesis of proteins requires energy.

Classify each of the following as exothermic or endothermic: b. The energy level of the products is higher than that of the reactants.

a. What is measured by the heat of reaction?

Classify each of the following as exothermic or endothermic: a. CH₄(g) + 2O₂(g) →∆ CO₂(g) + 2H₂O(g) + 802kJ

The equation for the formation of silicon tetrachloride from silicon and chlorine is (7.9) Si(s) + 2Cl₂(g) → SiCl₄(g) + 157 kcal b. Is the energy of the product higher or lower than the energy of the reactants?

Oxygen can be converted into ozone by the action of lightning or electric sparks: 3 O2(g) ⇌ 2 O3(g) For this reaction, ∆H = +69kcal/mol (+285 kj/mol) and K = 2.68 x 10^-29 at 25 °C. Is the reaction exothermic or endothermic?

In photosynthesis, green plants convert carbon dioxide and water into glucose (C6H12O6) according to the following equation: 6 CO2(g) + 6 H2O(l) → C6H12O6(aq) + 6 O2(g) Is the reaction endothermic or exothermic?