4.4g x 22.4 litres/44 g = 2.24 liters.

44 g of CO₂ contain 6.023x1023 mol of CO₂ 4.4 g Contains - ?

4.4g x 6.023 x 10²³ / 44g = 6.023 x 10²² mol

Keywords

Reactants, products, exothermic reaction, endothermic reaction Physical and chemical changes Primary or skelton Equation unit forumula, Precipitation, Co-efficient, atomic mass, standard temperature and pressure (STP) molar mass, avagadro’s number, gram molar volume.

What we have learnt

• A Chemical equation is the symbolic representation of a chemical change.
• A balanced chemical equation explains about reactants, products and their physical states during the reaction.
• A chemical equation should always be balanced according to the Law of conservation of mass.
• The chemical reaction in which heat is absorbed are called endothermic reactions and in which heat is evolved are exothermic reactions.
• A chemical equation containing simply symbols of elements and molecular formulae of the substances without balancing is known as primary or skeleton equation.
• The symbols of elements and formulae of the compounds should not be changed but only their co-efficient should be altered while balancing the chemical equation.
• Co-efficient should be least possible whole numbers.

Improve Your Learning

I. Reflections on concepts

1. What information do you get from a balanced chemical equation? (AS₁ )
2. Why should we balance a chemical equation? (AS₁ )
3. Balance the following chemical equations. (AS₁)
   
   (a) NaOH+ H₂ S0 ₄---> Na₂ SO₄ +H₂O

page no.31
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