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प्रश्न
Explain with examples what is meant by a 'mole' of a substance.
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उत्तर
A mole is the quantity of a substance whose mass in grams is equal in magnitude to the molecular mass of that substance in Daltons. Thus, the molecular mass of oxygen is 32 u, and therefore 32g oxygen is 1 mole of oxygen. The molecular mass of water is 18u. Therefore, 18g of water makes 1 mole of water.
1 mole of a compound is the mass of that substance in grams equal in magnitude to its molecular mass. The SI unit is mol.
Number of moles of substances (n) = `"Mass of substance in grams"/"Molecular mass of substance"`
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संबंधित प्रश्न
Which has more number of atoms, 100 grams of sodium or 100 grams of iron (given, atomic mass of Na = 23 u, Fe = 56 u)?
Calculate the molar mass of the following substance:
Nitric acid, HNO3
What is the mass of 1 mole of nitrogen atoms?
What is the mass of 10 moles of sodium sulphite (Na2SO3)?
Convert into mole.
12 g of oxygen gas
Convert into mole.
22 g of carbon dioxide
What is the mass of 0.5 mole of water molecules?
Fill in the following blanks :
0.5 mole of calcium element has a mass of ............... .
How many moles of O2 are there in 1.20 × 1022 oxygen molecules ?
If 0.2 mol of the following substance is required how many grams of that substance should be taken?
Sodium chloride
Fill in the blank.
One a.m.u. is the mass of ______ atom of C12.
Correct the following statement :
Equal masses of all gases under identical conditions contain the same number of molecules.
Find the number of molecules in 1.8 g of H2O.
Calculate the mass of 0.1 mole of the following:
Na2SO4.10H2O
(Ca = 40, Na = 23, Mg = 24, S = 32, C = 12, Cl = 35.5, O = 16, H = 1)
Calculate the mass of 0.1 mole of the following:
Mg
(Ca = 40, Na = 23, Mg = 24, S = 32, C = 12, Cl = 35.5, O = 16, H = 1)
Determine the number of molecules in a drop of water which weighs 0.09 g.
Correct the statement, if required.
Under the same conditions of temperature and pressure, equal volumes of all gases contain the same number of atoms.
Match the following.
| 1. | 8 g of O2 | - | 4 moles |
| 2. | 4 g of H2 | - | 0.25 moles |
| 3. | 52 g of He | - | 2 moles |
| 4. | 112 g of N2 | - | 0.5 moles |
| 5. | 35.5 g of Cl2 | - | 13 moles |
Compute the difference in masses of 103 moles each of magnesium atoms and magnesium ions.
(Mass of an electron = 9.1×10–31 kg)
If 0.2 mol of the following substance is required how many grams of that substance should be taken?
Calcium carbonate
