Question

PLEASE HELP ASAP !!! How to balance equations with brackets? Like Pb(NO3)2? How many of each element is there?

Answer 1

When you have those kind of compounds you have to multiply each element inside the bracket by the subscript outside the bracket. Here you have 1 Pb, 2 N and 6 O.

Step-by-step explanation:

Answer 2

Replace the formulas inside the parentheses with single letters

Step-by-step explanation:

Here's an equation with lots of parentheses.

(NH₄)₃PO₄ + Pb(NO₃)₂ ⟶ NH₄NO₃ + Pb₃(PO₄)₂

It looks impossible to balance, doesn't it?

One way to balance the equation is to recognize that the polyatomic ions (the formulas inside the parentheses) stay together.

Then we can make some substitutions.

Let A = NH₄, X = PO₄, and Y = NO₃

Then the equation becomes

A₃X + PbY₂ ⟶ AY + Pb₃X₂

Here's how to balance it.

1. Start with the most complicated formula, Pb₃X₂, and put a 1 in front of it.

A₃X + PbY₂ ⟶ AY + 1Pb₃X₂

2. Balance Pb

We have fixed three atoms of Pb on the right, so we need three atoms of Pb on the left. Put a 3 in front of PbY₂.

A₃X + 3PbY₂ ⟶ AY + 1Pb₃X₂

3. Balance X

We have fixed two atoms of X on the right, so we need two atoms of X on the left. Put a 2 in front of A₃X.

2A₃X + 3PbY₂ ⟶ AY + 1Pb₃X₂

4. Balance A

We have fixed 6 atoms of A on the left, so we need 6 atoms of A on the right. Put a 6 in front of AY.

2A₃X + 3PbY₂ ⟶ 6AY + 1Pb₃X₂

Every formula has a coefficient, and the equation is now balanced.

Next, we replace the original formulas in the equation.

The balanced equation is

2(NH₄)₃PO₄ + 3Pb(NO₃)₂ ⟶ 6NH₄NO₃ + 1Pb₃(PO₄)₂