# Q3 the molar enthalpy of combustion of sucrose r h o

• Essay
• 6
• 100% (5) 5 out of 5 people found this document helpful

This preview shows page 2 - 4 out of 6 pages.

Q3. The molar enthalpy of combustion of sucrose,rHo= is -5645 kJ mol-1. What term (one word) is used to describe a chemical reaction with a negative change in enthalpy?
Q4. Calculate the molecular weights of both sucrose and palmitic acid, by summing the contributions from C, H and O atoms and enter your data in the table below. (Useful data: relative atomic masses C12.01, H 1.01, O 16.00).Q5. Calculate the number of moles in 1.00 g of sucrose and of palmitic acid. Enter your answers in the table below. (Hint: n = m/MW).
Q6. Calculate the energy released by respiration of 1.00 g of sucrose and of palmitic acid. Enter your answers in the table below. (hint: use the number of mol from the previous Q, along with the molar enthalpy of combustion)Q7. Based on the energy released in respiration per gram, which is the more potent fuel source, sugaror fat? Is this consistent with the notion that each new CO bond made via oxidation releases energy?
Latrobe.edu.auCHEM101 - CHEMISTRY ESSENTIALS Scenario-Based Problem2
Summary Table. Fill in all the shaded table cells.QuantityUnitsSucrose (sugar)Palmitic Acid (fat)Molecular formula-C12H22O11C16H32O2Molar enthalpy of combustion,rHokJ mol-1-5645-9978Q4) molecular weight
Q5) moles in 1.00 g
Q8) O2required for daily energy quota of 8700 kJ(a) number of O2molecules inbalanced reaction-12 O2molecules(b) n O2mol18.494 mol(c) Volume O2L458.202 LGasesRespiration requires oxygen, but how much do we need in a day, or each minute? This is more than just a matter of curiosity for environments where air is in limited supply (e.g. in a submarine or space vessel, scuba diving, climbing in the Himalayas or trapped in an air pocket). You can get a rough estimate of this as follows by considering the oxygen required to produce the recommended daily energy quota for an adult of 8700 kJ (as seen on food labels). Q8. (a) According to the stoichiometry (molar ratios) of the balanced reaction, how many oxygen molecules are required for each sucrose molecule in respiration? Enter your answer in the table.(b) How many mole of O2are required to generate 8700 kJ of energy from sucrose? (The appendix provides examples of this type of calculation.)