Chemical compound of some chemicals - 6th calss

Compound	Elements/ Radicals With Valencies	Formula
Hydrochloric acid	H¹ Cl¹	HCl
Sulphuric acid	H¹(SO₄)²	H₂SO₄
Nitric acid	H¹(NO₃)¹	HNO₃
Sodium Carbonate	Na¹(CO₃)²	Na₂CO₃
Sodium nitrate	Na¹(NO₃)¹	NaNO₃
Calcium Chloride	Ca²Cl¹	CaCl₂
Calcium carbonate	Ca²(CO₃)²[or Ca¹(CO₃)¹]	CaCO₃
Potassium hydroxide	K¹(OH)¹	KOH

Differences between compounds & mixtures

Differences between compounds & mixtures

PROPERTY	COMPOUNDS	MIXTURES
1. combination of constituents	constituents are combined together chemically	constituents are combined together not chemically but physically only
2. ratio of constituents	same constituents are present in a fixed ratio	constituents can be present in any ratio
3. separation of constituents	constituent can be separated only by chemical methods	constituents can be separated by physical methods
4. properties	have properties different from those of their constituents	properties are those of their constituents
5. energy changes	often energy is absorbed or released during the formation of compounds	often no energy is absorbed or released when a mixture is formed

Valencies of some common elements and Radicals

Elements/ Radicals	Symbol	Valency
Hydrogen	H	1
Sodium	Na	1
Potassium	K	1
Copper	Cu	1 or 2
Mercury	Hg	1 or 2
Chlorine	Cl	1
Iodine	I	1
Nitrate	NO₃⁻	1
Calcium	Ca	2
Iron	Fe	2 or 3
Oxygen	O	2
Sulphur	S	2, 4 or 6
Sulphate	SO₄⁻²	2
Carbonate	CO₃⁻²	2
Aluminium	Al	3
Nitrogen	N	3 or 5
Phosphate	PO₄⁻³	3
Carbon	C	4