English Medium इयत्ता ९ - CBSE Question Bank Solutions

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64 g of oxygen gas contains ................ moles of oxygen 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)

How many moles of O2 are there in 1.20 × 1022 oxygen molecules ?

How many moles are there in 34.5 g of sodium ? (Atomic mass of Na = 23 u)

If 16 g of oxygen contains 1 mole of oxygen atoms, calculate the mass of one atom of oxygen.

How many atoms are there in 0.25 mole of hydrogen ?

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)

Calculate the mass in grams of 0.17 mole of hydrogen sulphide, H2S. (Atomic masses : H = 1 u, S = 32 u)

Show by means of calculations that 5 moles of CO2 and 5 moles of H2O do not have the same mass. How much is the difference in their masses ?

Calculate the mole ratio of 240 g of calcium and 240 g of magnesium. (Ca = 40 u ; Mg = 24 u)

Define mole. What are the two things that a mole represents.

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)

What is meant by ‘a mole of carbon atoms’ ?

How many moles of oxygen atoms are present in one mole of the following compounds ?

1. Al₂O₃
2. CO₂
3. Cl₂O₇
4. H₂SO₄
5. Al₂(SO₄)₃

Which of the following pair of elements represents a mole ratio of 1 : 1 ?

Which of the following correctly represents 360 g of water ?

1. 2 moles of H₂O
2. 20 moles of water
3. 6.022 × 10²³ molecules of water
4. 1.2044 × 10²⁵ molecules of water

The ratio of moles of atoms in 12 g of magnesium and 16 g of sulphur will be :

Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. Molar atomic mass of magnesium is 24g mol^–1.