ICSE ICSE Class 8 - CISCE Question Bank Solutions

What do you mean by a saturated solution ?

Give a reason for the following:

An excess of carbon dioxide increases the temperature of the earth.

Where is the nucleus of an atom situated? 

 Complete and balance the following equation:

H₂ + S → ___________

Complete and balance the following equation:

Zn +_________________→ZnCl₂ + H₂ 

Complete and balance the following equation:

CuO +__________→ Cu +___________

Complete and balance the following equation:

\[\ce{K + H2O -> }\]________+ ________

Complete and balance the following equation:

Fe + H2O →___________+____________

State a reason why, when hydrogen is passed over heated copper oxide, the resultant product formed, differs in colour from the original reactant.

With reference to oxidation & reduction reaction – complete the statement given by filling in the blanks with only the words (a) Addition (b) Removal.

‘Oxidation is a chemical reaction involving ____ of oxygen to a substance or ____ of hydrogen from a substance. Reduction on the otherhand involves ____ of hydrogen to a substance or ____ of oxygen from a substance.

If 5 g. of a solute is added to 50 ml. of a solvent at a particular temperature and the solution can dissolve more of the solute at that temperature – is the solution obtained a saturated or an unsaturated solution. Give reasons.

Explain the meaning of the term ‘saturated solution’. State two methods to convert a saturated solution to an unsaturated solution.

State how a ‘supersaturated’ solution differs from a ‘saturated solution’. State briefly how you would prepare a supersaturated solution using potassium chloride and water.

Explain in brief – Lod Rutherford’s experiment which led to the discovery of the atomic nucleus.

‘Electrons revolve around the nucleus in fixed orbits or shells called energy levels’. State how these energy levels are represented.

State what is meant by the ‘reactivity series of metals’

With reference to Water explain with suitable examples of how the reactivity of the metals could be differentiated.

With reference to Acid explain with a suitable example of how the reactivity of the metals could be differentiated.

Give a balanced equation for the reversible catalytic reaction involving nitrogen as one of the reactants.

Select the correct answer for the statement given below:

The catalyst used in the catalytic reaction involving the reactants nitrogen and hydrogen.