How many joules are there in 30.0 kcal? (1 cal = 4.184 J)

• A. 1.26 × 10^5 J
• B. 1.25 × 10^4 J
• C. 8.37 × 10^4 J
• D. 3.60 × 10^5 J

Answer: (A)

Verified step by step guidance

1. Identify the given quantity and the units to convert: you have 30.0 kilocalories (kcal) and want to convert this to joules (J).
2. Recall the conversion factors: 1 kilocalorie (kcal) is equal to 1000 calories (cal), and 1 calorie (cal) is equal to 4.184 joules (J).
3. First, convert kilocalories to calories using the relation: \$30.0\ \text{kcal} \times 1000\ \frac{\text{cal}}{\text{kcal}}$.
4. Next, convert calories to joules using the relation: \(\text{calories} \times 4.184\ \frac{\text{J}}{\text{cal}}\).
5. Multiply the values from the two conversions to find the total energy in joules: \$30.0 \times 1000 \times 4.184$ J.