4. Suppose a student performed a precipitation reaction and isolated his precipitate. Given the

data in the table below, what was the mass of the reactants before the reaction? Assume no

mass loss during the isolation of the precipitate.

mass of empty flask

54.275 g

mass of precipitate

1.240 g

mass of flask and contents after isolating precipitate

122.488 g

Mass of reactant = 69.453 g

Explanation:

Given dа ta:

Mass of empty flask = 54.275 g

Mass of precipitates = 1.240 g

Mass of flask and content after isolating the precipitates = 122.488 g

Mass of reactants = ?

Solution:

Mass of reactants must be equal to the mass of precipitates and content in flask after isolating the precipitates.

Mass of reactant = mass of precipitates+content in flask after isolating the precipitates

Mass of content in flask = Mass of flask and content after isolating the precipitates - mass of flask

Mass of content in flask = 122.488 g - 54.275 g

Mass of content in flask = 68.213 g

Mass of reactant:

Mass of reactant = mass of precipitates+content in flask after isolating the precipitates

Mass of reactant = 1.240 g + 68.213 g

Mass of reactant = 69.453 g