How can I balance this chemical equation? Sodium phosphate and calcium chloride react to form calcium phosphate and sodium chloride

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Answer 1 · 2014-07-23T18:26:55

This is a double replacement reaction. Here's how to balance double replacement equations

Your unbalanced equation is

#"Na"_3"PO"_4 + "CaCl"_2 → "Ca"_3("PO"_4)_2 + "NaCl"#

1. Start with the most complicated formula, #"Ca"_3("PO"_4)_2#.

Put a 1 in front of it. We have now fixed the number of #"Ca"# atoms and #"PO"_4# groups.

#"Na"_3"PO"_4 + "CaCl"_2 →color(red)(1)"Ca"_3("PO"_4)_2 + "NaCl"#

2. Balance #"Ca"#. Put a 3 in front of #"CaCl"_2#.

#"Na"_3"PO"_4 + color(blue)(3)"CaCl"_2 → color(red)(1)"Ca"_3("PO"_4)_2 + "NaCl"#

.

3. Balance #"PO"_4#. Put a 2 in front of #"Na"_3"PO"_4#.

#color(orange)(2)"Na"_3"PO"_4 + color(blue)(3)"CaCl"_2 → color(red)(1) "Ca"_3("PO"_4)_2 + "NaCl"#

4. Balance #"Na"#. Put a 6 in front of #"NaCl"#.

#color(orange)(2) "Na"_3"PO"_4 + color(blue)(3) "CaCl"_2 → color(red)(1)"Ca"_3("PO"_4)_2 + color(teal)(6) "NaCl"#

5. Every formula has a coefficient.

The equation should be balanced. Let's check.

Left hand side: #"6 Na; 2 PO"_4"; 3 Ca; 6 Cl"#
Right hand side: #"3 Ca; 2 PO"_4"; 6 Na; 6 Cl"#.

Everything checks. the balanced equation is

#"2Na"_3"PO"_4 + "3CaCl"_2 → "Ca"_3("PO"_4)_2 + "6NaCl"#