Question

An impure sample of lime weighing 0.150 g was reacted with 50.00 cm³:

a. Determine the limiting reactant.
b. Calculate the percentage purity of the lime sample.
c. Find the volume of gas evolved at standard temperature and pressure (STP).
d. Identify the type of reaction that occurred.

Answer 1

To determine the limiting reactant, convert quantities to moles and compare ratios. Calculate percentage purity by relating moles of product to the pure reactant. The volume of gas at STP can be found using the ideal gas law.

Step-by-step explanation:

Determining the Limiting Reactant and Percentage Purity

To find the limiting reactant in a chemical reaction, follow these steps:

1. Convert all reactant quantities (mass or volume) to moles using their molar masses or given densities.
2. Divide the number of moles of each reactant by its stoichiometric coefficient from the balanced equation to find the mole ratio.
3. The reactant with the lowest mole ratio is the limiting reactant.

For percentage purity, use the following steps:

1. React the impure sample and find the amount of product formed.
2. Convert the number of moles of product back to the moles of the pure reactant using the stoichiometry of the balanced equation.
3. Calculate the mass of the pure reactant that would form the determined moles of product.
4. Divide the mass of the pure reactant by the mass of the impure sample and multiply by 100 to get the percentage purity.

To find the volume of gas evolved at STP, use the ideal gas law with the volume formula V = nRT/P, where 'n' is the moles of gas, 'R' is the ideal gas constant, and 'T' is the temperature in Kelvin. The pressure 'P' should be 1 atm as that's the standard pressure.

The type of reaction can be determined by analyzing the reactants and products. Common types include synthesis, decomposition, single-replacement, double-replacement, and combustion reactions.