Last seen: Jan 25, 2021
The valency of nitrogen in NH3 is 3.
The symbol of cadmium is Cd.
The formula for quick lime is CaO.
The atomicity of K2Cr2O7 is 11.
Molar mass of Al2O3 = 2 × 27 + 3 × 16 = 54 + 48 = 102 g ∵ 102 g of Al2O3 contains = 2 x 6.022 x 1023 Al3+ions ∴ 0.051 g of Al2O3 contains = ...
Mass of 1 mole of S8 = 8 × 32 = 256 ∵ 256 g of S8 contains = 6.022 x 1023 molecules ∴ 16 g of S8 contains = 6.022 x 1023/256 x 16 = 3.76 x 1022 mo...
(a) Mass of 1 mole of oxygen atom = 16 u Mass of 0.2 mole of oxygen atoms = (16 × 0.2) u = 3.2 u (b) Mass of 1 mole of H2O molecule = (1 x 2 + 16)...
(a) Molar mass of O2 = 2 x 16 = 32 g ∴ Number of moles in 12 g of O2 = Given mass/Molar mass = 12/32 = 0.375 mole (b) Molar mass of H2O =...
(a) Mass of nitrogen atom = number of moles x atomic mass = 1 x 14 = 4 g (b) Mass of aluminium atom = 4 x atomic mass = 4 x 27 = 108 g (c) Mas...
(a) Molar mass of C2H2 = 2 x atomic mass of C + 2 x atomic mass of H = (2 x 12 + 2 x 1)u = (24 + 2)u = 26u (b) Molar mass of S = 8 × atomic mass...
(a) Quick lime is CaO. Elements present are calcium and oxygen. (b) Hydrogen bromide is HBr. Elements present are hydrogen and bromine. (c) Baking...
A polyatomic ion is a group of atoms carrying positive or negative charge. e.g., Polyatomic ions - Symbol Ammonium - NH4+ Hydroxide - OH- Nit...
C(3 g) + O2(8 g) → CO2(11 g) Total mass of reactants = mass of C + mass of O2 = 3 + 8 = 11g Total mass of reactants = total mass of products Hen...
We know that, % of any element in a Compound = Mass of element/Mass of Compound x 100 % of boron = 0.096/0.24 x 100 = 40% % of oxygen = 0.144/0....
100 g of sodium Number of sodium atoms = given mass/molar x 6.022 x 1023 = 100/23 x 6.022 x 1023 = 2.62 x 1024 100 g of iron: Number of ...
Atomic mass of carbon = 12g ∵ 1 mole of C atoms weights = 12 g ∵ 6.022 x 1023 atoms of carbon have mass = 12 g ∴ 1 atom of carbon has mass = 1...
Formula unit mass of ZnO = atomic mass of Zn + atomic mass of O = (65 + 16)u = 81 u Formula unit mass of Na2O = 2 x atomic mass of Na + atomic mas...
Molecular mass of H2 = 2x atomic mass of H = 2 x 1 u = 2 u Molecular mass of O2 = 2x atomic mass of O = 2 x 16 u = 32 u Molecular mass of Cl2 ...
(i) 3 atoms because H2S molecule has two atoms of hydrogen and one atom of sulphur. (ii) 5 atoms because PO3-4 ion has one atom of phosphorus and fo...
The chemical formula of a compound is a symbolic representation of its composition. e.g., formula of calcium oxide. Thus, chemical formula of calciu...