the total kilojoules for one cup of orange juice that contains 24 g of carbohydrate, no fat, and 3 g of protein
Express your answer to two significant figures and include the appropriate units.
To calculate the total kilojoules for one cup of orange juice, we need to know the energy content of the carbohydrates and proteins.
Carbohydrates have 4 kilocalories per gram (kcal/g), which is equivalent to 16.7 kilojoules per gram (kJ/g). Therefore, 24 g of carbohydrates provide:
24 g * 16.7 kJ/g = 400.8 kJ
Proteins also have 4 kilocalories per gram (kcal/g), which is equivalent to 16.7 kilojoules per gram (kJ/g). Therefore, 3 g of protein provide:
3 g * 16.7 kJ/g = 50.1 kJ
Since fat is not mentioned in the question, we assume it is not present. Hence, there is no additional energy contribution from fat.
Adding the energy contributions from carbohydrates and proteins, the total kilojoules for one cup of orange juice is:
400.8 kJ + 50.1 kJ = 450.9 kJ
Expressed to two significant figures, the total kilojoules for one cup of orange juice is approximately 450 kJ.
To determine the total kilojoules for one cup of orange juice, we need to calculate the energy contributed by each macronutrient (carbohydrate, fat, and protein) separately and then sum them up.
1. Carbohydrates:
Carbohydrates provide approximately 4 kilocalories (kcal) per gram. To convert kilocalories to kilojoules, we multiply by 4.184.
Total energy from carbohydrates = 24 g * 4 kcal/g * 4.184 kJ/kcal.
2. Fat:
Since the orange juice contains no fat, it does not contribute any calories or kilojoules.
3. Protein:
Protein also provides approximately 4 kilocalories (kcal) per gram.
Total energy from protein = 3 g * 4 kcal/g * 4.184 kJ/kcal.
To find the total energy, we add the energy contributions from carbohydrates and protein:
Total energy = energy from carbohydrates + energy from protein.
Now, let's compute the total energy:
Total energy from carbohydrates = 24 g * 4 kcal/g * 4.184 kJ/kcal = 402.816 kilojoules.
Total energy from protein = 3 g * 4 kcal/g * 4.184 kJ/kcal = 50.208 kilojoules.
Total energy = 402.816 kJ + 50.208 kJ.
Rounding to two significant figures, the total energy for one cup of orange juice is approximately 453 kilojoules or 450 kJ.
Therefore, the total kilojoules for one cup of orange juice is 450 kJ (to two significant figures).