When a 3.22 g sample of an unknown hydrate of sodium sulfate, na2so4 . x h2o (s), is heated, h2o (molar mass 18 g) is driven off. the mass of the anhydrous na2so4 (s) (molar mass 142 g) that remains is 1.42g. the value of x in the hydrate is

Explanation:

This is like an empirical formula question, except that you are finding the molar ratio of compounds instead of atoms.

Step 1. Gather the information in one place.

M_r:                                            142             18

           Na₂SO₄·xH₂O(s) ⟶ Na₂SO₄(s) + xH₂O(g)

m/g:              3.22                      1.42

Step 2. Calculate the mass of the water

Mass of H₂O = mass of Na₂SO₄·xH₂O – mass of Na₂SO₄

= 3.22 – 1.42 = 1.80 g

Step 3. Calculate the moles of each product

Na₂SO₄:

     H₂O:

Step 4. Calculate the molar ratios

, so the formula of the compound is Na₂SO₄·10H₂O

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.