Advertisements
Advertisements
प्रश्न
True or false
New substances are formed in a chemical change.
पर्याय
True
False
Advertisements
उत्तर
True
APPEARS IN
संबंधित प्रश्न
How do the following help in bringing about a chemical change?
pressure.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction is a chemical reaction in which there is
- removal of hydrogen
- removal of oxygen
- addition of oxygen
- none of these
FILL IN THE BLANK
The new substances formed during a chemical reaction are called the ..................
What are homogenous reactions ?
Is kerosene an electrolyte or a non-electrolyte ?
Fill in the blank
A new substance is formed in a _______ change.
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
Choose the correct option from the bracket and explain the statement giving a reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
Addition of an aqueous solution of ZnSO4 to an aqueous solution of BaCl2 is an example of ______ reaction.
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of dilute acid to an active metal.
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of dilute hydrochloric acid to silver nitrate.
Explain the term chemical reaction with special reference to reactants and products.
The chemical change is ______.
Analogy:
H2O: Water:: NaCl: ______.
Write some materials prepared by chemical changes.
Classify each of the following, as a physical or a chemical change. Give reasons.
(a) Drying of a shirt in the sun.
(b) Rising of hot air over a radiator.
(c) Burning of kerosene in a lantern.
(d) Change the colour of black tea by adding lemon juice to it.
(e) Churning of milk cream to get butter.
The simplest method of preventing rusting of iron is to coat it with oil, grease, or paint. The reason being ______.
Iron and rust are the same substances.
Explain how the painting of an iron gate prevents it from rusting.
Give an example where heat, light, and sound are produced during a chemical change.
Chemical changes are important in our day-to-day life. Give examples.
