Does every time when H2 and O2 combine, form only water?
Not every time. The product of any reaction depends on the condition the reactions i.e. temperature, pressure, catalyst etc... 2H2+O2→2H2O (water)
Apart from water, H2 and O2 combine to form hydrogen peroxide(H2O2) also.
H2+O2→H2O2 (hydrogen peroxide)
The mass of a particular substance is remain same even 1 mole of atom or 1 molecules of of any substance contains 6.022 ×10 23 atom /molecules justify?
Atomic mass or molecular it is expressed in g mol-1 i.e. it is the mass of 1 mole (6.03x1023) of atoms or molecules which is always a fixed quantity.
Molecular mass of H2O is 18 g
i.e. mass of 1 mole (6.03x1023 ) water molecule = 18g
Mass of 1 water molecule = 18/6.03x1023 = 2.988 x 10-23 g
We know that 1 g = 1/ 1.66 x10-24 amu
2.988 x 10-23 g =(2.988 x 10-23 g) /1.66 x10-24 amu = 18 amu or 18 u
What is atomicity?
Atomicity of ion may be defined as the number of atom present in that ion .
· Al3+ atomicity is 1.
· O2 - atomicity is 2.
Atomicity is the number of atoms of an element present in one molecule of that element.
For example, there are 2 atoms of hydrogen present in H2 molecule. So its atomicity is 2.
The gases can be
Monatomic, example: Helium (He)Carbon (C)
Diatomic, example: hydrogen (H2)
tri atomic , example: ozone (O3)
Polyatomic, example: sulphur (S8).
Give some examples of non ionic compounds?
Non ionic compounds...
CO2, C6H12O6, C6H6, CH4
How does the seventh postulate of Dalton's satisfy laws of constant proportional?
The seventh postulate of Dalton's law states that In a given compound, the relative number and types of atoms are constant.
The above statement means that the number of atoms of different elements in a compound is fixed and does not vary. We can say that the composition of a compound is fixed as same atoms will always combine in the same ratio.
Thus a molecule of water will always have 2 atoms of hydrogen and one atom of oxygen.
Remember: The postulate of Dalton’s atomic theory that “atoms can neither be created nor be destroyed” was a result of the law of conservation of mass.
What is the mass of 0.5 mole of Cl2 gas?
Molecular mass of Cl2 = 2 x atomic mass of Cl = 2 x35.5 =70 u
Mass = molar mass x number of moles= 70u x 0.5 = 35.5 u
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