How many milliliters of 0.150 M BaCl₂ are needed to react completely with 35.0 mL of 0.200 M Na₂SO₄? How many grams of BaSO₄ will be formed?

Verified step by step guidance

1. Write the balanced chemical equation for the reaction: \[ \text{BaCl}_2 (aq) + \text{Na}_2\text{SO}_4 (aq) \rightarrow \text{BaSO}_4 (s) + 2\text{NaCl} (aq) \]
2. Determine the moles of \( \text{Na}_2\text{SO}_4 \) using its concentration and volume: \[ \text{moles of } \text{Na}_2\text{SO}_4 = 0.200 \text{ M} \times 0.035 \text{ L} \]
3. Use the stoichiometry of the balanced equation to find the moles of \( \text{BaCl}_2 \) needed, which is a 1:1 ratio with \( \text{Na}_2\text{SO}_4 \).
4. Calculate the volume of \( 0.150 \text{ M} \) \( \text{BaCl}_2 \) solution required using the moles of \( \text{BaCl}_2 \) and its concentration: \[ \text{Volume} = \frac{\text{moles of } \text{BaCl}_2}{0.150 \text{ M}} \]
5. Calculate the mass of \( \text{BaSO}_4 \) formed using the moles of \( \text{BaSO}_4 \) (same as moles of \( \text{Na}_2\text{SO}_4 \)) and its molar mass: \[ \text{mass of } \text{BaSO}_4 = \text{moles of } \text{BaSO}_4 \times \text{molar mass of } \text{BaSO}_4 \]

Key Concepts

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. It allows us to calculate the amounts of substances consumed and produced in a reaction based on balanced chemical equations. Understanding stoichiometry is essential for determining how much of one reactant is needed to completely react with another.

Molarity

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution. It is expressed in moles per liter (M). In this question, the molarity of BaCl₂ and Na₂SO₄ solutions is crucial for calculating the volume of BaCl₂ needed to react with a given volume of Na₂SO₄, as it directly relates to the number of moles present in each solution.

Precipitation Reaction

A precipitation reaction occurs when two soluble salts react in solution to form an insoluble product, known as a precipitate. In this case, the reaction between BaCl₂ and Na₂SO₄ produces BaSO₄, which is insoluble in water. Understanding this concept is important for predicting the formation of BaSO₄ and calculating its mass based on the stoichiometry of the reaction.