Washing soda is a hydrated compound whose formula can be written na2co3 i zh2o, where z is the number of moles of h2o per mole of na2co3. when a 2.123 g sample of washing soda was heated at 130°c, all of the water of hydration was lost, leaving 0.787 g of anhydrous sodium carbonate. calculate the value of z.

The value of z is 10,.

Explanation:

Mass of washing soda =  2.123 g

Mass of sodium carbonate = 0.787 g

Mass of water = 2.123 g-0.787 g =1.336 g

Wasing soda → Sodium carbonate + water

Moles of  sodium carbonate =

Moles of water =

According to reaction , 1 mol of sodium carbonate obtained with z moles of water.

z = 9.99 ≈ 10

the answers are

c and c