Questions: Complete the following table. Round each of your answers to 3 significant digits. food energy content when eaten ------------ cal kcal kJ three ounces of cooked sirloin steak 2.40 × 10^5 240. 100. an ear of cooked corn 8.5 × 10^4 85.0 an ounce of breakfast corn flakes 460.

Complete the following table. Round each of your answers to 3 significant digits.

food energy content when eaten
------------
cal kcal kJ
three ounces of cooked sirloin steak 2.40 × 10^5 240. 100.
an ear of cooked corn 8.5 × 10^4 85.0
an ounce of breakfast corn flakes 460.

Transcript text: Complete the following table. Round each of your answers to 3 significant digits. \begin{tabular}{|l|c|c|c|} \hline \multirow{2}{*}{ food } & \multicolumn{3}{|c|}{ energy content when eaten } \\ \cline { 2 - 4 } & cal & kcal & kJ \\ \hline \begin{tabular}{l} three ounces of cooked sirloin \\ steak \end{tabular} & $2.40 \times 10^{5}$ & 240. & 100. \\ \hline an ear of cooked corn & $8.5 \times 10^{4}$ & 85.0 & $\square$ \\ \hline an ounce of breakfast corn flakes & $\square$ & $\square$ & 460. \\ \hline \end{tabular}

Solution

Solution Steps

Step 1: Convert kcal to kJ for cooked corn

To convert kcal to kJ, we use the conversion factor $1 \text{ kcal} = 4.184 \text{ kJ}$.

Given: \[ 85.0 \text{ kcal} \]

Calculation: \[ 85.0 \text{ kcal} \times 4.184 \text{ kJ/kcal} = 355.64 \text{ kJ} \]

Rounding to 3 significant digits: \[ 355.64 \approx 356 \]

Step 2: Convert kJ to kcal for breakfast corn flakes

To convert kJ to kcal, we use the conversion factor $1 \text{ kJ} = \frac{1}{4.184} \text{ kcal}$.

Given: \[ 460 \text{ kJ} \]

Calculation: \[ 460 \text{ kJ} \times \frac{1 \text{ kcal}}{4.184 \text{ kJ}} = 109.92 \text{ kcal} \]

Rounding to 3 significant digits: \[ 109.92 \approx 110 \]

Step 3: Convert kcal to cal for breakfast corn flakes

To convert kcal to cal, we use the conversion factor $1 \text{ kcal} = 1000 \text{ cal}$.

Given: \[ 110 \text{ kcal} \]

Calculation: \[ 110 \text{ kcal} \times 1000 \text{ cal/kcal} = 110000 \text{ cal} \]

Rounding to 3 significant digits: \[ 110000 \approx 1.10 \times 10^5 \]

Final Answer

\[ \begin{array}{|l|c|c|c|} \hline \multirow{2}{*}{ food } & \multicolumn{3}{|c|}{ energy content when eaten } \\ \cline { 2 - 4 } & \text{cal} & \text{kcal} & \text{kJ} \\ \hline \begin{tabular}{l} three ounces of cooked sirloin \\ steak \end{tabular} & 2.40 \times 10^{5} & 240. & 100. \\ \hline \text{an ear of cooked corn} & 8.5 \times 10^{4} & 85.0 & \boxed{356} \\ \hline \text{an ounce of breakfast corn flakes} & \boxed{1.10 \times 10^5} & \boxed{110} & 460. \\ \hline \end{array} \]

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