Plants use CO2 (g) and H2O (l) and energy from the sun to create glucose (C6H12O
ID: 718566 • Letter: P
Question
Plants use CO2 (g) and H2O (l) and energy from the sun to create glucose (C6H12O6) and oxygen gas. What is the minimum amount of energy from the sun required to produce 5 g of glucose in this way? ?Hf of glucose is -1260 kJ/mol.Explanation / Answer
Plants use CO2 (g) and H2O (l) and energy from the sun to create glucose (C6H12O6) and oxygen gas. What is the minimum amount of energy from the sun required to produce 5 g of glucose in this way? ?Hf of glucose is -1260 kJ/mol ANSWER: 6CO2(g) +6 H2O (l) + Sunlight---------> 6 O2 (g) + C6H12O6 (s) Delta Hf og glucose = -1260 KJ/mol Delta Hf of CO2 is -395.5 KJ/mol Delta Hf of H2O is -285.5 KJ/mol Delta Hf of O2 is 0KJ/mol. Step 1: Delta H of the reaction = (sum of delta Hf of product - sum of delta Hf reactants). = ((-1260 KJ/mol)+ 0) -((6*(-395.5 KJ/mol)+6*(-285.5 KJ/mol)) = ((-1260 KJ/mol) -(-2373-1713)KJ/mol = +2826 KJ/mol. Step 2: Convert Mass to moles. Moles = 5g/180g/mol = 0.0278 moles of C6H12O6. Step 3: Energy required for 0.0278 moles of C6H12O6= (0.0278 moles) x(+2826 KJ/mol) = +78.563 KJ the minimum amount of energy from the sun required to produce 5 g of glucose is +78.563 KJ