Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. Molar atomic mass of magnesium is 24g mol–1.
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The atomic number of an element is 5 and mass number is 11. Find the number of electrons, protons and neutrons present in an atom of it.
Number of electrons (Z = 5) = 5 Number of protons (Z = 5) = 5 Number of neutrons (A = Z) = 11 – 5 = 6 Since the atomic number is...
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(a) Calculate the number of moles in 112 g of iron. (b) Calculate the mass of 0.5 moles of sugar (C12H22O11).
(a) 1 mole of iron (Fe) = 56 g (molar mass) Since 56 g of iron = 1 mol Therefore, 112 g of iron= 1/ 56 ×112 mol = 2 mol (b) Molar...
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Calculate the number of moles present in (a) 60 g of calcium. (b) 3.011 × 1023 number of oxygen atoms.
(a) Number of moles of Ca = Given mass of calcium / Molar mass of calcium = 60 / 40 = 1.5 moles (b) Number of moles = Given number of molecules...
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Calculate the ratio by number of atoms for Magnesium sulphide. [Atomic mass of Mg => 24, S => 32]
Atomic mass of Mg = 24 Atomic mass of S = 32 Ratio of Mg and S in Magnesium sulphide = 24:32 = 3:4 Mass ratio / Atomic mass of Magnesium (Mg) =...
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Calculate the number of moles is 52 g of He (Helium) [Atomic mass: O = 16 u, He = 4 u]
Number of moles = Given mass / Molar mass = 52/ 4 = 13 moles.
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The mass of single atom of an element is 2.65 × 10−23 g. Calculate its atomic mass. [NA= 6.022 × 1023 mol−1 ]
Mass of 1 atom = 2.65 × 10−23 g Therefore, mass of 6.022 × 1023 atoms = 2.65 × 10−23× 6.022 × 1023 g = 15.96 g ≈ 16 g mol−1 Therefore, the atomic...
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Compute the difference in masses of 10^3 moles each of magnesium atoms and magnesium ions. (Mass of an electron = 9.1×10–31 kg)
A Mg2+ ion and Mg atom differ by two electrons. 103 moles of Mg2+ and Mg atoms would differ by 103 × 2 moles of electrons Mass of 2 ×103 moles of electrons...
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Why should a magnesium ribbon be cleaned before burning in air.
When magnesium ribbon is exposed to air, it reacts with oxygen in the air to form magnesium oxide. This oxide layer interferes with the burning of magnesium ribbon. Thus, the...
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What is redox reaction? When a magnesium ribbon burns in air with a dazzling flame and forms a white ash, is magnesium oxidised or reduced? Why?
i. The reaction in which one reactant gets oxidised and the other reactant gets reduced is called redox reaction. ii. When a magnesium ribbon burns in air with a dazzling flame...
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i. What do you see when a magnesium ribbon is burnt? Is magnesium oxidised or reduced in this reaction? ii. Define corrosion.
When magnesium ribbon is burnt, dazzling white flame is observed and there is formation of white ash. Magnesium is said to be oxidised as it is combining with oxygen. ii. The...
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