19. Give the names of the elements and number of atoms of
those elements, present in the following compounds.
(a) Sodium sulphate (b) Quick lime
(c) Baking soda (NaHCO3) (d) Ammonia
(e) Ammonium dichromate
Answers
19. (a) Sodium sulphate:- Na₂SO₄
Elements:- Na S O
No. of atom:- 2 1 4
(b) Quick lime:- CaO
Elements:- Ca O
No. of atoms:- 1 1
(c) Baking soda:- NaHCO₃
Elements:- Na H C O
No. of atoms:- 1 1 1 3
(d) Ammonia:- NH₃
Elements:- N H
No. of atoms:- 1 3
(e) Ammonium dichromate:- (NH₄)₂Cr₂O₇
Elements:- N H Cr O
No. of atoms:- 2 8 2 7
Answer:
(a)Sodium Sulphate - Na2SO4
Elements present: Sodium of 2 atoms, Sulphur of 1 atom & Oxygen of 4 atoms
(b)Quicklime - CaO
Elements present: Calcium of 1 atom & oxygen of 1 atom
(c)Baking Soda - NaCHO3
Elements present: Sodium of 1 atom, Carbon of 1 atom, Hydrogen of 1 atom & Oxygen of 3 atoms
(d)Ammonia - NH3
Elements present: Nitrogen of 1 atom & Hydrogen of 3 atoms
(e)Ammonium dichromate - (NH4)2Cr2O7
Elements present: Nitrogen of 2 atoms, Hydrogen of 8 atoms, Chromium of 2 atoms , Oxygen of 7 atoms
Explanation:
For the (e) part of the Question (NH4)2
So, The no. of atoms of one element in the bracket should be multiplied with the no. outside the bracket. Then you will get the accurate no. of atoms of a particular element.
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