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

Question

134025 views around the world

You can reuse this answer
Creative Commons License

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"#