Unit 3 Chemistry 3.5

What is the formula to calculate the efficiency of energy transformation during combustion?

If a fuel has a chemical energy of 5000 kJ and produces 1500 kJ of useful energy, what is the efficiency of the energy transformation?

• 30%

• 40%

• 50%

• 60%

Which macronutrient provides the highest energy value per gram?

• Carbohydrates

• Proteins

• Fats and oils

• Vitamins

Calculate the energy value of 10 grams of carbohydrates, given that carbohydrates provide 17 kJ per gram.

• 170 kJ

• 1700 kJ

• 17 kJ

• 1.7 kJ

If a food item contains 5 grams of protein, how much energy does it provide, considering proteins provide 17 kJ per gram?

• 85 kJ

• 50 kJ

• 25 kJ

• 100 kJ

How much energy is provided by 8 grams of fats, given that fats provide 37 kJ per gram?

• 296 kJ

• 370 kJ

• 2960 kJ

• 37 kJ

Which of the following is NOT a factor affecting the efficiency of energy transformation during combustion?

• Type of fuel

• Temperature

• Colour of the flame

• Combustion conditions

What is the primary reason fats provide more energy per gram compared to carbohydrates and proteins?

• Fats have a higher density

• Fats contain more carbon-hydrogen bonds

• Fats are more easily digested

• Fats are stored in larger quantities

If a food item contains 10 grams of carbohydrates, 5 grams of protein, and 2 grams of fat, what is the total energy content?

• 319 kJ

• 3740 kJ

• 37.4 kJ

• 37400 kJ

Which of the following statements is true regarding energy transformation in the human body?

• All consumed energy is converted to useful work

• Some energy is lost as heat during metabolism

• Energy from food is stored indefinitely

• The body can only use energy from carbohydrates