UESTION 1 A 156gsample of sodium bicarbonate NalHCo3 is deco

UESTION 1 A 15.6gsample of sodium bicarbonate (NalHCo3) is decomposed by heating How many grams of Nazcog remains? 2NaHCOs (6)NaC(6) Co2 (g)+ H20() 15.6g 5.8g 9.89 10.0g

Solution

Molar mass of NaHCO3,
MM = 1*MM(Na) + 1*MM(H) + 1*MM(C) + 3*MM(O)
= 1*22.99 + 1*1.008 + 1*12.01 + 3*16.0
= 84.008 g/mol

mass of NaHCO3 = 15.6 g
mol of NaHCO3 = (mass)/(molar mass)
= 15.6/84.008
= 0.1857 mol

According to balanced equation
mol of Na2CO3 formed = (1/2)* moles of NaHCO3
= (1/2)*0.1857
= 0.0928 mol


Molar mass of Na2CO3,
MM = 2*MM(Na) + 1*MM(C) + 3*MM(O)
= 2*22.99 + 1*12.01 + 3*16.0
= 105.99 g/mol


mass of Na2CO3 = number of mol * molar mass
= 0.0928*105.99
= 9.8 g
Answer: 9.8 g