You have to find the number of moles of water and calcium sulfate.
to find the mass of water you subtract 3.87 by 4.89 to get 1.02g water and we are given taht the mass of calcium sulfate is 3.87g
then find the moles of water and calcium sulfate in the sample
1.02/18=0.05667mol water
3.87/136.2=0.0284 mol water
now you have to find how many moles there are per one mole of calcium sufate.
0.05667/0.0284=1.994 which can be rounded to 2 mol water for ever 1 mol calcium sulfate
therefore the formula for this CaSO₄·2H₂O and is called calcium sulfate dihydrate.
I hope this helps
<span>The electron configuration of lead is [Xe] 6s2, 4f14, 5d10, 6p2 according to the Aufbau principle.</span>
•Saturated Solution: A solution in which no more solute can be dissolved in a definite amount of solvent at a given temperature is called a saturated solution.
Example: A soda is a saturated solution of carbon dioxide in water. This is why, when the pressure is released, carbon dioxide gas forms bubbles.
•Unsaturated solution: It is a solution in which more of solute can be dissolved at a given temperature. In this, addition of solute is possible till the solution reaches the point of saturation.
Example: Salt dissolved in water even sugar dissolved in water is an Unsaturated solution if the quantity of dissolved Salt/Sugar is below the saturation point.
Mg(NO3)2 => <span>Magnesium nitrate
hope this helps!</span>
Answer
Manganese II oxide
Thank you
