Journal Entry:

One way to remove potentially toxic substances from a water source is to precipitate out the harmful ions. Consider the removal of copper ions by precipitation. 2NaOH(aq) + Cu(NO₃)(aq) → 2NaNO₃(aq) + Cu(OH)₂(s)

Suppose you add 100 mL of 0.10 M NaOH(aq) to 100 mL of 0.10 M Cu(NO₃)₂(aq).

1. Have you added equal numbers of moles of the two substances? Explain your thinking.

2. Have you added equal numbers of grams of the two substances? Explain your thinking.

3. Have you added enough NaOH (aq) to remove all the copper from the solution? Explain your thinking.

Learning Intentions

• We will learn the definition for a mole ratio
• We will learn how to combine reactants to make the most product from a reaction

Closing Task:

You can determine the best mole ratio to produce the most product.

Content Standards being covered:

Student understands what the letters and numbers stand for in a compound formula, can use those letter and numbers to determine how many of each type of element there are in a formula.

Student can create mathematical representations of chemical reactions and use them to make calculations about products and reactants.

Students can use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction. (HS-PS1-7 and CCC Energy and Matter)