English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

Write Short Notes on (A) Mitochondria

What are main functional regions of the cell?

Which organelle is the "power plant" of eukaryotic cell. Write in brief its functions.

Draw a diagrammatic sketch of oxygen cycle in nature.

An element has an atomic number of 11 and its mass number is 23. What is the arrangement of electrons in the shells? State nuclear composition of an atom of the element.

If the number of electrons in an ion Z3– is 10, the atomic number of element Z will be :

The atomic number of an element E is 16. The number of electrons in its ion E2– will be :

The number of electrons in an ion Y2+ is 10. The atomic number of element Y is most likely to be :

The atom of an element X contains 17 protons, 17 electrons and 18 neutrons whereas the atom of an element Y contains 11 protons, 11 electrons and 12 neutrons.

1. What type of ion will be formed by an atom of element X ? Write the symbol of ion formed.
2. What will be the number of (i) protons (ii) electrons, and (iii) neutrons, in the ion formed from X ?
3. What type of ion will be formed by an atom of element Y ? Write the symbol of ion formed.
4. What will be the number of (i) protons (ii) electrons, and (iii) neutrons, in the ion formed from Y ?
5. What is the atomic mass of (i) X, and (ii) Y ?
6. What could the elements X and Y be ?

What is the numerical value of Avogadro number ?

What name is given to the number 6.022 × 1023 ?

What name is given to this number ?

What is the number of molecules in 1.5 moles of ammonia ?

Calculate the number of molecules in 4 g of oxygen.

If 32 g of sulphur has x atoms, then the number of atoms in 32 g of oxygen will be :

If 12 gram of carbon has x atoms, then the number of atoms in 12 grams of magnesium will be :

Which of the following has the maximum number of atoms ?

What weight of oxygen gas will contain the same number of molecules as 56 g of nitrogen gas ?

(O = 16 u ; N = 14 u)

What mass of nitrogen, N2, will contain the same number of molecules as 1.8 g of water, H2O ?

(Atomic masses : N = 14 u ; H = 1 u ; O = 16 u)

If one gram of sulphur contains x atoms, calculate the number of atoms in one gram of oxygen element.

(Atomic masses : S = 32 u ; O = 16 u)