Answer:
Note that melting and vaporization are endothermic processes in that they absorb or require energy, while freezing and condensation are exothermic process as they release energy.
Answer:
True => ΔH°f for C₆H₆ = 49 Kj/mole
Explanation:
See Thermodynamic Properties Table in appendix of most college level general chemistry texts. The values shown are for the standard heat of formation of substances at 25°C. The Standard Heat of Formation of a substance - by definition - is the amount of heat energy gained or lost on formation of the substance from its basic elements in their standard state. C₆H₆(l) is formed from Carbon and Hydrogen in their basic standard states. All elements in their basic standard states have ΔH°f values equal to zero Kj/mole.
The answer is: the mass of oxygen is 16.95 grams.
The overall balanced photosynthesis reaction:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
m(C₆H₁₂O₆) = 15.90 g; mass of glucose.
n(C₆H₁₂O₆) = m(C₆H₁₂O₆) ÷ M(C₆H₁₂O₆).
n(C₆H₁₂O₆) = 15.9 g ÷ 180.18 g/mol.
n(C₆H₁₂O₆) = 0.088 mol; amount of glucose.
From chemical reaction: n(C₆H₁₂O₆) : n(O₂) = 1 : 6.
n(O₂) = 6 · 0.088 mol.
n(O₂) = 0.53 mol; amount of oxygen.
m(O₂) = 0.53 mol · 32.00 g/mol.
m(O₂) = 16.95 g; mass of oxygen.
