Can anybody example this topic 'Law of chemical combination' - Science - Atoms and Molecules

Question

Can anybody example this topic 'Law of chemical combination'?

Abhishek Ranjan · Accepted Answer

Dear Student,
There are basically four laws of chemical combination -
Law of conservation of mass, Law of
constant proportion, Law of Multiple
Proportions and Law of Reciprocal
Proportions
The law of conservation of mass states
that the mass of a closed system will remain constant in a chemical
reaction In other words, mass can neither be created nor destroyed
in a chemical reaction This law was first formulated by Antoine
Laurent Lavoisier in 1789
For example, 100 g of mercuric oxide, when heated in a
closed test tube, decomposes to produce 92 6 g of mercury and 7 4 g
of oxygen gas
2 HgO (s) → 2Hg (l) + O
2
Total mass of the reactant = 100 g
Total mass of the products = 92 6 + 7 4 g = 100
g
Hence, during the decomposition reaction, matter is
neither created nor destroyed Here, matter is made up of tiny
mercuric (Hg) and oxygen (O) atoms The given reaction shows that
atoms can neither be created nor destroyed in chemical
reactions
According to the law of constant
proportion, a chemical substance always contains the same
elements in a fixed proportion by mass, irrespective of its source
The law of constant proportion is also known as the law of
definite proportion This law, which was introduced by
Proust, stated that ‘in a compound, the elements are always
present in definite proportions by mass’
For example, pure water obtained from any source (well,
river, lake, or sea) and from any country (India, Russia, America,
etc ) will always contain two hydrogen atoms and one oxygen atom
Hydrogen and oxygen respectively combine together in the ratio of
1:8 by mass to form water The ratio by the number of atoms for
water will always be H : O = 2 : 1 Thus, 18 g of water contains 2 g
of hydrogen and 16 g of oxygen Similarly, in ammonia, nitrogen
makes up 14/17 of the mass of ammonia while hydrogen makes up the
remaining 3/17 of the mass Irrespective of the source from which
ammonia is obtained, it will always contain nitrogen and hydrogen
in the ratio of 14: 3 by mass Thus, 17 g of ammonia contains 14 g
of nitrogen and 3 g of hydrogen, and 34 g of ammonia contains 28 g
of nitrogen and 6 g of hydrogen

The law of multiple proportions states that when
two elements form two or more compounds between them, the ratio of
the masses of the second element in each compound can be expressed
in the form of small whole numbers
This law was proposed by John Dalton, and it is a combination of
the previous laws
Example - Carbon combines with oxygen to form two different
compounds (under different circumstances) One is the most common
gas CO2 and the other is CO Do they obey the law of
multiple proportions?

Yes, they do obey the law of multiple proportions Let's verify
it
We know that the mass of carbon is 12 u and the mass of oxygen
is 16 u
So, we can say that 12 g of carbon combines with }32 g of oxygen to
form CO2
Similarly, 12 g of carbon combines with 16 g of oxygen to form
CO
So, the ratio of oxygen in the first and second compound is 2:1 =
32 / 16 = 2, which is a whole number

The law of reciprocal proportions states that when
two different elements combine with the same quantity of the third
element, the ratio in which they will do so will be the same or a
multiple of the proportion in which they combine with each other
This law was proposed by Jeremias Ritcher in 1792
Example :
Oxygen and sulphur react with copper to create copper oxide and
copper sulphide, respectively Sulphur and oxygen also react with
each other to form SO2â€‹
Therefore,
in CuS, Cu : S = 63 5 : 32
in CuO, Cu : O = 63 5:16
S : O = 32 : 16 = 2
: 1

Now in SO2â€‹, we have
S : O = 32 : 32 = 1
: 1
Thus the ratio between the two ratios is the following:
2 / 1 : 1 / 1 = 2 : 1,
which is a simple multiple ratio

Regards