A 2.914-g sample of gypsum, a hydrated salt of calcium sulphate, CaSO4, is heated at a temperature
greater than 170 °C in a crucible until a constant mass is reached. The mass of the anhydrous CaSO4
salt is 2.304 g. Calculate the % by mass of water in the hydrated calcium sulphate salt.
www.jiskha.com/questions/776638/A-2-914-gram-sample-of-gypsum-a-hydrated-salt-of-calcium-sulfat-CaSO4-is-heated
To calculate the mass percent of water in the hydrated calcium sulphate salt, we need to find the mass of water lost during the heating process.
First, let's find the mass of water lost:
Mass of hydrated salt = 2.914 g
Mass of anhydrous salt = 2.304 g
Mass of water lost = Mass of hydrated salt - Mass of anhydrous salt
= 2.914 g - 2.304 g
= 0.610 g
Now, to find the mass percent of water, we divide the mass of water lost by the initial mass of the hydrated salt and multiply by 100.
Mass percent of water = (mass of water lost / mass of hydrated salt) × 100
= (0.610 g / 2.914 g) × 100
= 20.94%
Therefore, the mass percent of water in the hydrated calcium sulphate salt is approximately 20.94%.