Title: Double Displacement Reaction Lab

Ability: 7^th and 8^th Grade

Time: One class Period

Discipline: Physical Science

NJ Core Curriculum Content Standards:

Science: 5.1, 5.6

Mathematics: 4.1,

Purpose:

To demonstrate double displacement reactions, and how to write balanced chemical reactions.

Materials:

1 spot plate

6 pipets

6 chemical solutions

Write solution name below:

Solution 1:_____________________

Solution 2:_____________________

Solution 3:_____________________

Solution 4:_____________________

Procedure:

On the table below, write down whether the combination of the solutions in each row and column is a clear solution, or if it is a precipitate (solid). Don’t forget to write down the color of the precipitates. A list of solubility rules and charges of cations (positively charged ions) and polyatomic anions (negatively charged ions) will be handed out to aid in identification of the precipitates and to aid in proper charge balancing of the compounds.

In the final section a properly balanced equation must be written out for each reaction.

Ex: Reaction of Column 1 and row 2 if known #1 BaSO₄ (barium sulfate) and known #2 is NaOH (sodium hydroxide)

1. Write down the compounds reacting on the right hand side.

BaSO₄ + NaOH

2. Look up the charges for the ions in each compound. (Hint: the positive and negative charges must equal 0 in each compound)

Ba²⁺SO₄^2- (+2)+(-2) = 0

Na¹⁺OH^1- (+1) +(-1) = 0

These compounds are properly charge balanced

3. Rearrange ions

A B + C D → A D + C B

Ba²⁺SO₄^2- + Na1⁺OH^1- → Ba²⁺OH^1- + Na1⁺SO₄^2-

(+2) + (-2) = 0 (+1) + (-1) = 0 (+2) +(-1) = 1 (+1) + (-2) = -1

Note that the charges on AC and BD do not add to zero. The charges must be balanced.

3. Balance charges on products if necessary.

Ba2+SO4-2 (aq) + Na1+OH1- (aq) → Ba2+ (OH1-)2 (s) SO42- (aq)

(+2) + (-2) = 0 (+1) + (-1) =0 (+2) + (-1*2) = 0 (+1*2) + (-2) =0

Data [ Write in Clear Solution or Precipitate(solid)]

	Compound 1	Compound 2	Compound 3	Compound 4
Compound 1	No reaction
Compound 2		No reaction
Compound 3			No reaction
Compound 4				No reaction