There are 4 significant figures! Start counting after the first non-zero digit :)
Hope this helps.
Answer: 8.30 g of calcium sulfate are produced from 10 grams of lithium sulfate.
Explanation:
To calculate the moles :
According to stoichiometry :
1 mole of 
require = 1 mole of 
Thus 0.061 moles of will require=
of 
Thus is the limiting reagent as it limits the formation of product and is the excess reagent.
As 1 mole of give = 1 mole of 
Thus 0.061 moles of give = of
Mass of 
Thus 8.30 g of calcium sulfate are produced from 10 grams of lithium sulfate.
Answer: A supersaturated solution will not contain undissolved solute because the undissolved solute will be indicative of saturated solution.
Explanation:
A supersaturated solution is the one that consists of more than the maximum concentration of the solute in the solvent that is being dissolved at a given temperature. A saturated solution is the one in which the maximum concentration of solute has been dissolved in the solvent and no additional solute can be dissolved further.
According to the given statement, a solution with undissolved solute is a saturated solution rather a supersaturated solution.
