b A hardworking human brain operates at about 25 Js What mas

(b) A hardworking human brain operates at about 25 J/s. What mass of glucose must be consumed to sustain that metabolic rate for an hour?

Q1)

a) The reaction occuring will be

C6H12O6 + 9O2 -------- 6CO2 + 6H2O

Delta H(rxn) = Delta H(products) - Delta H(Reactants)

=> 6 * Delta H(CO2(f)) + 6 * Delta H(H2O(l)) - Delta H (C6H12O6)

=> 6(-393.51) + 6(-285.83) + 1268

=> -2808 kJ

For human brain to work for 1 hour = 25 J/s * 1 hr * 60 min/1hr * 60 seconds/1 min

=> 25 * 3600

=> 9 * 10^4 Joules

Number of moles of glucose = 9 * 10^4/2.828 * 10^6 = 3.1824 * 10^(-2) moles

Molar mass of glucose (C6H12O6) = 6 * 12 + 12 * 1 + 6 * 16 = 180 gm/mol

Mass of glucose = 3.1824 * 10^(-2) mol * 180 gm/mol

=> 5.728 grams of glucose