The sum total of the number of protons and neutrons present in the nucleus of an atom is called atomic weight.
Molecular weight: The sum total of the atomic weights of various atoms present in a substance is called molecular weight. For example:
Molecular weight of CaCO_{3} = ( 40 + 12 + 16×3)
= (40 + 12+ 48)
= 100
Similarly,
Molecular weight of water = H_{2}O
= (1×2 + 16)
= 18
The molecular weight of a substance which is expressed in terms of gram is called gram molecular weight. For example:
The gram molecular weight of CaCO_{3} is 100 gm.
Each mole of any substance contains 6.023 x 10^{23} particles or ions or atoms or molecules and this number is called Avogrado number.
The collection of 6.023 x 10^{23} particles or ions or atoms of a substance is called its one mole. Mole is equal to the gram molecular weight of a substance. For example:
Gram molecular weight of CaCO_{3} = 100 gm.
1 mole of CaCO_{3} = 100 gm.
100 gram of CaCO_{3} = 6.023 x 10^{23} particles
It is defined as the change in concentration of any one of the reactants or products per unit time to complete the reaction.
Factors affecting rate of reaction:
2KClO_{3} = 2KCl + 3O_{2} (Balanced chemical equation)
or, 2(39 + 35 + 3 × 16) = 2 (39 + 35) + 3(2 × 16)
or, 2 × 122 = 148 + 96
or, 244 = 148 + 96
244 gms of potassium chlorate on strongly heating gives 148 gms of potassium chloride and 96 gms of oxygen.
∵ 244 gms of KClO_{3} will yield 148 gms of KCl
1 gm of KClO_{3} will yield 148/244 gms of KCl
∴ 10 gms of KClO_{3 }will yield (10 × 148) / 244 = 6.06 gms of KCl
∵ 244 gms of KClO_{3} will yield 96 gms of O_{2}
1 gm of KClO_{3} will yield 96 / 244 gms of O_{2}
∴ 10 gms of KClO_{3 }will yield (10 × 96 ) / 244 = 3.93 gms of O_{2 }
Balanced chemical equation: CaCO_{3} → CO_{2} + CaO
Molecular weight: 40 + 12 + (3 × 16) = [12 + (2 × 16)] + (40 + 16)
or, 100 = 44 + 56
100 gms of CaCO_{3} gives 44 gms of CO_{2} and 56 gms of CaO
1 gm of CaCO_{3} gives 44/100 gms of CO_{2} and 56/100gms of CaO
10 gms of CaCO_{3} gives 44/100 ×10 gms of CO_{2} and 56/100 ×10 gms of CaO
So, 10 gms of CaCO_{3} gives 4.4 gms of CO_{2} and 5.6 gms of CaO.
Balanced chemical equation: 2Mg + O_{2} → 2MgO
Molecular weight: (2 × 24) + (2 × 16) = 2 (24 + 16)
or, 48 + 32 = 80
48 gm of Mg gives 80 gm of MgO
or, 1 gm of Mg gives 80/48 gm of MgO
or, 10 gm of Mg gives 80/48 × 10 gm of MgO
So, 10 gm of Mg gives 16.66 gm of MgO.
Here, balanced chemical equation: 2KOH + H_{2}SO_{4} → K_{2}SO_{4} + 2H_{2}O
Molecular weight:
2 (39 + 16+ 1) + [(2 × 1) + 32 + (4 × 16)] = [(39 × 2) + 32 + (4 × 16)] + 2 [(2 × 1) + 16]
or, 112 + 98 = 174 + 36
112 gm of KOH gives 174 gm of K_{2}SO_{4}
1 gm of KOH gives 174/112 gm of K_{2}SO_{4}
10 gm of KOH gives 174/112 × 10 gm of K_{2}SO_{4}
So, 10 gm of KOH gives 15.32 gm of K_{2}SO_{4 }
When the concentration of reacting compounds is increased, the reacting molecules become close together due to increase of the number of reacting molecules. As the result, the reacting molecules collide together to increase the rate of chemical reaction.
The amount of the reactant that is converted into the product in per unit time is called the rate of chemical reaction.
When the temperature of the reactants increases, the kinetic energy of the molecules of the reactants also increases. As the result, the molecules of the reactants collide together faster to increase the rate of chemical reaction.
The sum total of the number of protons and neutrons present in the nucleus of an atom is called _______.
_______ is the collection of 6.023 x 10^{23} particles or ions or atoms of a substance.
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Shikshya
What is 4 mile of carbon dioxide?
Jan 29, 2017
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Anzila
How many moles is there in 110gm of co2 ?
Dec 31, 2016
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