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Multiple Choice
If you have 9 moles of CaCl2 and an excess of Na3PO4, how many moles of NaCl can be produced according to the following reaction?CaCl2 + Na3PO4 → Ca3(PO4)2 + NaCl
A
3 moles
B
18 moles
C
27 moles
D
9 moles
Verified step by step guidance
1
Write the balanced chemical equation for the reaction. Start by balancing the number of atoms for each element on both sides. The unbalanced equation is: \(\mathrm{CaCl_2 + Na_3PO_4 \rightarrow Ca_3(PO_4)_2 + NaCl}\).
Balance calcium (Ca) atoms first. Since there are 3 Ca atoms in \(\mathrm{Ca_3(PO_4)_2}\), place a coefficient of 3 in front of \(\mathrm{CaCl_2}\): \$3\ \mathrm{CaCl_2 + Na_3PO_4 \rightarrow Ca_3(PO_4)_2 + NaCl}$.
Balance phosphate (\(\mathrm{PO_4}\)) groups next. There are 2 phosphate groups in \(\mathrm{Ca_3(PO_4)_2}\), so place a coefficient of 2 in front of \(\mathrm{Na_3PO_4}\): \$3\ \mathrm{CaCl_2 + 2\ Na_3PO_4 \rightarrow Ca_3(PO_4)_2 + NaCl}$.
Balance sodium (Na) atoms. On the left, there are \$2 \times 3 = 6\( Na atoms from \)2\ \mathrm{Na_3PO_4}\(. Therefore, place a coefficient of 6 in front of \)\mathrm{NaCl}\( on the right: \)3\ \mathrm{CaCl_2 + 2\ Na_3PO_4 \rightarrow Ca_3(PO_4)_2 + 6\ NaCl}$.
Use the mole ratio from the balanced equation to find moles of \(\mathrm{NaCl}\) produced. For every 3 moles of \(\mathrm{CaCl_2}\), 6 moles of \(\mathrm{NaCl}\) are produced. Set up the proportion: \(\frac{6\ \mathrm{mol\ NaCl}}{3\ \mathrm{mol\ CaCl_2}} = \frac{x\ \mathrm{mol\ NaCl}}{9\ \mathrm{mol\ CaCl_2}}\). Solve for \(x\) to find the moles of \(\mathrm{NaCl}\) produced.