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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
Convert into mole.
20 g of water
- The percentage composition of a gas is:
Nitrogen 82.35%, Hydrogen 17.64%. - Find the empirical formula of the gas. [N = 14, H = 1]
One of the following elements has an atomicity of ‘one’. This element is :
What is the mass of 0.2 mole of oxygen atoms ?
Fill in the following blanks :
60 g of carbon element are .............. moles of carbon atoms.
Fill in the following blanks :
0.5 mole of calcium element has a mass of ............... .
If 16 g of oxygen contains 1 mole of oxygen atoms, calculate the mass of one atom of oxygen.
What is the mass of 5 moles of sodium carbonate (Na2CO3) ?
(Atomic masses : Na = 23 u ; C = 12 u ; O = 16 u)
How many moles are represented by 100 g of glucose, C6H12O6 ? (C = 12 u, H = 1 u, O = 16 u)
Prove the Following :
One mole of any gas contains th e same number of molecules.
Given that the relative molecular mass of copper oxide is 80, what volume of ammonia (measured at STP) is required to completely reduce 120g of copper oxide? The equation for the reaction is :
3CuO + 2NH3 → 3Cu + 3H2O + N2
Calculate the number of moles and number of molecules present in 1.4 g of ethylene gas. What is the volume occupied by the same amount of ethylene?
Calculate the mass of 0.1 mole of carbon dioxide.
[Atomic mass: S = 32, C = 12 and O = 16 and Avogadro's number = 6 × 1023]
A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure.
(a) Find the number of moles of hydrogen present
(b) What weight of CO2can the cylinder hold under similar conditions of temperature and pressure? (H = 1 C = 12, O = 16)
(c) If the number of molecules of hydrogen in the cylinder is X, calculate the number of CO2 molecules in the cylinder with the same conditions of temperature and pressure.
(d) State the law that helped you to arrive at the above result.
Define the term:
Gram atom
Find the number of molecules in 3.2 g of SO2.
What mass of Ca will contain the same number of atoms as are present in 3.2 g of S?
Calculate the number of atoms in the following:
52 moles of He
Correct the statement, if required.
The relative atomic mass of an element is the number of times one molecule of an element is heavier than `1/12` the mass of an atom of C12.
What is Molar volume of a gas?
