Here's how to write the molecular equation for the reaction between aqueous barium nitrate and lithium sulfate:

1. Identify the reactants:

* Barium nitrate: Ba(NO₃)₂ (aq)

* Lithium sulfate: Li₂SO₄ (aq)

2. Determine the products:

This reaction is a double displacement reaction, where the cations and anions switch partners. The products will be:

* Barium sulfate: BaSO₄ (s) (Barium sulfate is insoluble in water, so it forms a precipitate)

* Lithium nitrate: LiNO₃ (aq)

3. Write the unbalanced equation:

Ba(NO₃)₂ (aq) + Li₂SO₄ (aq) → BaSO₄ (s) + LiNO₃ (aq)

4. Balance the equation:

To balance the equation, we need to make sure the number of each type of atom is the same on both sides.

* Ba: Already balanced (1 on each side)

* NO₃: 2 on the left, 1 on the right. Place a coefficient of 2 in front of LiNO₃

* Li: 2 on the left, 2 on the right.

* SO₄: Already balanced (1 on each side)

The balanced molecular equation is:

Ba(NO₃)₂ (aq) + Li₂SO₄ (aq) → BaSO₄ (s) + 2LiNO₃ (aq)