Question

1. Calculate the atomic masses (u or amu)
Formula Calculations /Formula mass

KBr

CaCl2

Na2CO3

(NH4)3PO4  

2.Balance the following chemical equations?

1. H2 +Cl2àHCl

2. AgNO3 + H2SàAg2S + HNO3

3. P + O2àP2O3

4. HCl + Ba(OH)2 à BaCl2 + H2O

5. H2O2àO2+H2O

Answer 1

Sol"=> ?) calculate the atomic masses cu or amu) Formula calculations formula mass as KBV 3 atomic mass of K = 39 u = 39X1 = 394: atomic mass of Br = 80 u = 80x1 = 80 U. i. Formule mass of KBr = 39+80=ligu. b) cache =) atomic mass of ca = 40 u. atomic mass of .cl .= 35.5 u x 2 = 71u. .: Formula mass of Callz = 40+7) = 111 u. C) Na2CO3 =) atomic mass of pla = 23 x2 = 46 . s t ole atomic mass of c = 12 x1 = 12 u. Cutomic mass of o. 16X3 = 48 u . Formula mass of dachz = 46+12+48 = 106u. d) (NH4)₂ POL =) atomic muss of N = 14*3 =42 u. atomic mass of H = 1x 12 = 12 u altomic mess of p = 31*1 = 31 u e atomic mass of 0 3 16 X4 - 64 u ... Formula mass of (NH4)2PO4 = 42+12+31+64 = 149u. u .

Gol"=> 2) Balance the following chemical equation as H₂ t cl₂ Hel. =) Hydrogen reacts with chlorine to form hydrogen chloride. This is a synthesis reaction =) Balance enucetion- no balance this cluation use 2 coefficient in Brodvet side Hel. Hence balance equation is 1 H₂ t cle > 2 HCl b) Agro, + H₂S Ag₂ S + HNO3 => silver nitruda recets with hydrogen sulfide to form silver sulfide and nitric acid. This receton is double displacement recetion. -) Balunce equation TO bulunce this equation in recetant side use 2 coefficient on Agrlo, and in product side use a coefficient on HNO3. Hence balance equation is 2 AgNO3 + H₂S - Ag2S + 2 HNO3 c) pt 02 - P2O3 =) Phosphorus reuets with oxygen to form phosphorus trioscide. This revelion is called synthesis receliun.

=) Bulunee equation's to balance this equcetion, in recetant side use 4 coefficient on P & 3 coefficient on O2, and in product side use 2 coefficient on P203. Hence beelance quation is 4P.+ 302 - 2 P202 d) Helt Bacola Baelt H2o => Hydrogen chloride receets with banum hydroscide to form barium chloride and water. This is double displacement recution, =) Buluinee equation :- In recetant side use 2 cuefficient and in Product side use a coefficient on the. Hence balance. equation is . | 2HCl + Bacon), - Buela +2120 . e) H202 - Ozt the o Decomposition of hydrogen peroxide gives oxygen and waiter This is decomposition reaction. 5) Bulance equation. In reuetunt side use 2 coefficient on H202 f in Product side use 2 coefficient on the Hence balance equation is 2 H₂O2 - Ozt2H2O