For each precipitation reaction, calculate how many grams of the first reactant are necessary to completely react with 55.8 g of the second reactant. a. 2 KI(aq) + Pb(NO3)2(aq) → PbI2(s) + 2 KNO3(aq) b. Na2CO3(aq) + CuCl2(aq) → CuCO3(s) + 2 NaCl(aq) c. K2SO4(aq) + Sr(NO3)2(aq) → SrSO4(s) + 2 KNO3(aq)

Verified step by step guidance

1. Identify the balanced chemical equation for each reaction to determine the stoichiometry between the reactants.
2. Calculate the molar mass of the second reactant (55.8 g) for each reaction.
3. Convert the mass of the second reactant to moles using its molar mass.
4. Use the stoichiometry from the balanced equation to find the moles of the first reactant needed to completely react with the moles of the second reactant.
5. Convert the moles of the first reactant to grams using its molar mass.

Key Concepts

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation. It involves using mole ratios derived from the coefficients of the balanced equation to determine how much of each substance is needed or produced. Understanding stoichiometry is essential for solving problems related to the amounts of reactants and products in a reaction.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all atoms in a molecule. Knowing the molar mass of reactants allows for the conversion between grams and moles, which is crucial for stoichiometric calculations in precipitation reactions.

Precipitation Reactions

Precipitation reactions occur when two aqueous solutions react to form an insoluble solid, known as a precipitate. These reactions can be represented by balanced chemical equations, which show the reactants and products involved. Understanding the formation of precipitates helps in predicting the outcome of reactions and calculating the amounts of reactants needed for complete reactions.