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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:
Ethyne, C2H2
Calculate the molar mass of the following substance:
Hydrochloric acid, HCl
What is the mass of 0.5 mole of water molecules?
Choose the correct answer from the options given below:
The ratio between the number of molecules in 2g of hydrogen and 32g of oxygen is:
[Given that H = 1, O = 16]
What is a group of 6.022 × 1023 particles known as ?
What is the mass of 5 moles of sodium carbonate (Na2CO3) ?
(Atomic masses : Na = 23 u ; C = 12 u ; O = 16 u)
What weight of each element is present in 1.5 moles of sodium sulphite, Na2SO3 ?
(Atomic masses : Na = 23 u ; S = 32 u ; O = 16 u)
Which of the following correctly represents 360 g of water ?
- 2 moles of H2O
- 20 moles of water
- 6.022 × 1023 molecules of water
- 1.2044 × 1025 molecules of water
Fill in the blank
One gram atom of an element contains ______ atoms.
Fill in the blank
Avogadro's number is equal to ______
Calculate the weight of one molecule of oxygen.
[Avogadro’s number = 6 × 1023, O = 16 ]
Calculate the number of molecules in one Kg of calcium chloride.
How many grams of Al are present in 0.2 mole of it?
How many grams of H2O are present in 0.2 mole of it?
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)
Calculate the number of atoms in the following:
52 g of He
Solid ammonium dichromate decomposes as:
\[\ce{(NH4)2Cr2O7 -> N2 + Cr2O3 + 4H2O}\]
If 63 g of ammonium dichromate decomposes. Calculate the quantity in moles of nitrogen formed.
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 |
How many grams are there in the following?
4 moles of the phosphorous molecule, P4
