Q. 273.8( 6 Votes )
State the two important laws of chemical combination. How Dalton’s atomic theory explains the two Laws?
The two important laws of chemical combination are:
i) Law of constant proportion:
The law states that “in a chemical substance, the elements are always present in definite proportions by mass.
For example: In ammonia (NH3), nitrogen and hydrogen are always present in the ratio of 14:3 by mass, whatever the method
or source from which it is obtained.
In water, hydrogen and oxygen are always present in the ratio of 1:8 by mass, whatever the method or source from which water is obtained.
ii) Law of conservation of mass:
According to the law of conservation of mass states, atoms are neither created nor destroyed in a chemical reaction. This means that the total mass of the products formed in a chemical reaction must be equal to the mass of reactants consumed.
Sum of mass of reactants = Sum of masses of prodcuts
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With the help of example, explain the law of conservation of mass.Together with Science
What is meant by the law of conservation of mass? If 12 g of C is burnt in the presence of O2, how much CO2 will be formed?
[Atomic mass of C = 12 u, O = 16 u]
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(a) Name (i) liquid X (ii) gas Y, and (iii) gas Z
(b) What is the ratio to the mass of element Z to the mass of element Y in the liquid X?
(c) Which law of chemical combination is illustrated by this example?
(d) Name two sources of liquid X.
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(a) What is (i) solid P (ii) gas Q, and (iii) solid R.
(b) What is the total mass of Q and R obtained from 50 g of P?
(c) How does the total mass of Q and R formed compare with the mass of P taken?
(d) What conclusion do you get from the comparison of masses of products and reactant?
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During an experiment hydrogen (H2) and oxygen (O2) gases reacted in an electric are to produce water as
follows: 2H + O2 2H2O
The experiment is repeated three times and data tabulated as shown below:
During 3rd experiment the researcher forgot to list masses of H2 and O2 used. So, if the law of constant proportion is correct then find mass of O2 used during 3rd experiment.All In One - Science
In a compound such as water, the ratio of the mass of hydrogen to the mass of oxygen is always:Evergreen - Science
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The correct observation is that of student.All In One - Science