14.1.3b Balanced Diet and Calorific Value (MCQ-Hard)

A 1.5 g sample of dried carbohydrate (calorific value 16.7 kJ g⁻¹) is completely combusted in a calorimeter to heat 100 g of water. If the specific heat capacity of water is 4.2 J g⁻¹ °C⁻¹, what is the theoretical temperature increase of the water?

During a polar expedition in sub-zero temperatures, an explorer requires 18000 kJ per day. If they consume a meal containing 200 g of fats and 400 g of carbohydrates, what percentage of their daily energy requirement does this single meal provide?

Two people live in a cold climate: Person A is a tall, thin teenager, and Person B is a shorter, muscular adult of the same weight. Why might Person A require a higher calorie intake despite having less muscle mass?

An athlete’s target daily intake is 3500 kcal. To optimize long-term energy, they want 25% of their energy to come from fats (37.6 kJ g⁻¹). How many grams of fat should they consume? (Use 1 kcal = 4.2 kJ)

In a school laboratory experiment using a simple calorimeter (a test tube of water over a spirit burner), students consistently find that their calculated calorific values for food are lower than the official values on food labels. What is the most scientifically sound explanation?