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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
What is the mass of 10 moles of sodium sulphite (Na2SO3)?
What is the mass of 0.5 mole of water molecules?
A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure
1) Find the number of moles of hydrogen present.
2) What weight of CO2 can the cylinder hold under similar conditions of temperature and pressure? (H = 1, C = 12, O = 16)
3) If the number of molecules of hydrogen in the cylinder is X, calculate the number of CO2 molecules in the cylinder under the same conditions of temperature and pressure.
4) State the law that helped you to arrive at the above result.
Fill in the following blanks :
60 g of carbon element are .............. moles of carbon atoms.
What name is given to the amount of substance containing this number of atoms ?
How many moles of calcium carbonate (CaCO3) are present in 10 g of the substance ? (Ca = 40 u ; C = 12 u ; O = 16 u)
Calculate the mole ratio of 240 g of calcium and 240 g of magnesium. (Ca = 40 u ; Mg = 24 u)
Prove the Following :
One mole of any gas contains th e same number of molecules.
Define the term Relative atomic mass.
Explain the term:
Gram mole
Fill in the blank
Avogadro's number is equal to ______
A sample of ammonium nitrate when heated yields 8.96 litres of steam (measured at STP)
NH4NO3 → N2O + 2H2O
What volume of dinitrogen oxide is produced at the same time as 8.96 L of steam?
The equation for the burning of octane is:
\[\ce{2C8H18 + 25O2 -> 16CO2 + 18H2O}\]
How many moles of carbon dioxide are produced when one mole of octane burns?
If phosphorus is considered to contain P4 molecules, then calculate the number of moles in 100g of phosphorus?
Correct the statement, if required.
One mole of chlorine contains 6.023 x 1010 atoms of chlorine.
1 mole of any substance contains ______ molecules.
One mole of any gas occupies ______ ml at S.T.P.
N2 + 3H2 → 2NH3
(The atomic mass of nitrogen is 14, and that of hydrogen is 1)
1 mole of nitrogen (______ g) +
3 moles of hydrogen (______ g) →
2 moles of ammonia (______ g)
Calcium chloride when dissolved in water dissociates into its ions according to the following equation.
\[\ce{CaCl2} (aq) → {Ca^{2+} (aq) + 2{Cl}- (aq)}\]
Calculate the number of ions obtained from CaCl2 when 222 g of it is dissolved in water.
Deduce the number of molecules of the following compound in the given quantity.
8.8g carbon dioxide
