Question 22.2: Energy from ATP Hydrolysis A person might burn 2600 kcal run......

STEP 1 State the given and needed quantities.

STEP 2 Write a plan to convert the given unit to the needed unit.

\text{kilocalories}\ \ \xrightarrow[]{\begin{array}{l}\text{Molar energy}\\\text{factor}\end{array}}\ \ \text{moles of ATP}\ \ \xrightarrow[]{\begin{array}{l}\text{Molar}\\\text{mass}\end{array}}\ \ \text{grams of ATP}

STEP 3 State the equalities and conversion factors.

\begin{aligned} & 1\ mole \text { of ATP }=7.3\ kcal \\ & \frac{7.3\ kcal }{1\ mole \text { ATP }} \text { and } \frac{1\ mole \text { ATP }}{7.3\ kcal } \end{aligned}

\begin{aligned} & 1 \text { mole of ATP }=507\ g \text { of ATP } \\ & \frac{507\ g\ ATP }{1\ mole \text { ATP }} \text { and } \frac{1\ mole \text { ATP }}{507\ g\ ATP } \end{aligned}

STEP 4 Set up the problem to calculate the needed quantity.

2600 \cancel{\text { kcal }} \times \frac{1 \cancel{\text { mole ATP }}}{7.3 \cancel{\text { kcal }}} \times \frac{507 g \text { ATP }}{1 \cancel{\text { mole ATP }}}=1.8 \times 10^5 g \text { of ATP }