Calcium carbonate, CaCO_{3}, in antacids reacts with HCl in the stomach to reduce acid reflux.
2HCl(aq) + CaCO_{3}(s) \longrightarrow CO_{2}(g) +H_{2}O(l) +CaCl_{2}(aq)
How many liters of CO_{2} are produced at 752 mmHg and 24 °C from a 25.0-g sample of calcium carbonate?
STEP 1 State the given and needed quantities.
Table 1
STEP 2 Write a plan to convert the given quantity to the needed moles.
grams of CaCO_{3} \boxed{Molar Mass} → moles of CaCO_{3} \boxed{Mole-mole factor } → moles of CO_{2}
STEP 3 Write the equalities and conversion factors for molar mass and mole–mole factors.
1 mole of CaCO_{3} = 100.09 g of CaCO_{3} 1 mole of CaCO_{3} = 1 mole of CO_{2}
\frac{100.09 \space g \space CaCO_{3}}{1 \space mole \space CaCO_{3}} and \frac{1 \space mole \space CaCO_{3}}{100.09 \space g \space CaCO_{3}} \frac{1 \space mole \space CaCO_{3}}{1 \space mole \space CO_{2}} and \frac{1 \space mole \space CO_{2}}{1 \space mole \space CaCO_{3}}
STEP 4 Set up the problem to calculate moles of needed quantity.
25.0 \space \cancel {g \space CaCO_{3}} \times \frac{1 \space \cancel{mole \space CaCO_{3}}}{100.09 \space \cancel {g \space CaCO_{3}}} \times \frac{1 \space mole \space CO_{2}}{1 \space \cancel{mole \space CaCO_{3}}} = 0.250 \space mole \space of \space CO_{2}
STEP 5 Convert the moles of needed quantity to volume using the ideal gas law equation.
V =\frac{nRT}{P}
V =\frac{0.250 \space \cancel{mole} \space \times \space \frac{62.4 \space L · \cancel{mmHg}}{\cancel{mole} · \cancel K} \space \times \space 297 \space \cancel K}{752 \space \cancel {mmHg}}=6.16 \space L \space of \space CO_{2}
Table 1 :
ANALYZE THE PROBLEM |
Given | Need | Connect |
25.0 g of CaCO_{3} P = 752 mmHg T = 24 °C + 273 = 297 K |
V of CO_{2}(g) | ideal gas law, PV = nRT molar mass |
|
Equation | |||
2HCl(aq) + CaCO_{3}(s) \longrightarrow CO_{2}(g) +H_{2}O(l) +CaCl_{2}(aq) |