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प्रश्न
A chemical equation is a statement that describes a chemical change in terms of
पर्याय
symbols and formulae
energy
number of atoms
colours
उत्तर
symbols and formulae.
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संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Iron pipes coated with zinc do not get rusted easily.
Name three biochemical catalysts found in the human body.
Give reason.
Wasp sting is treated with vinegar.
What are oxides ?
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Miscible liquids having slightly different boiling points can be separated by the
- evaporation
- distillation
- fractional distillation
- sedimentation
FILL IN THE BLANK
In a double decomposition precipitation reaction both the reactants must be ............ soluble.
Explain the type of reactions on the basis of the direction of reaction.
Write true or false :
No new substance is formed during a chemical reaction.
State four conditions necessary for a chemical reaction to take place.
Explain by writing a word equation.
Bubbles are seen on adding lemon juice to baking soda.
Give an example of a reaction where the following are involved
Electricity
What do you observe? When
Barium chloride is added to sodium sulphate solution
Complete and balance the following reaction:
\[\ce{Pb(NO3)2 ->[\Delta]}\]
Select the correct answer for the following options:
The gas which reacts with oxygen to give a neutral liquid.
Give reason for the following:
A characteristic change of colour is seen when a piece of iron is added to copper [II] sulphate solution.
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 water to quicklime.
Complete the table given below.
| Heat on ammonium dichromate | Name of neutral gas evolved |
Complete the table given below.
| Addition of dil. H2SO4 to KHCO3 | Name of residue obtained |
True or False. If false, give the correct answer.
Taking a glass of water and freezing it by placing it in the freezer is a chemical change.
Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.
Burning of paper is the best example of ______ change.
Chemists identify gypsum as a natural indicator.
Arrange the following statements in correct sequence:
- One side is water-loving and other water-hating molecules.
- When you agitate the cloth, the dirt is surrounded by many molecules and taken away from the cloth.
- The dirt surrounded by the detergent molecules floats in the water making it dirty.
- Finally, the cloth is clean.
- The detergent molecules have two sides.
- Water hating goes and joins with dirt and oil in the cloth while the water-loving joins with the water molecules.
Which of the following is/are true when milk changes into curd?
- Its state is changed from liquid to semi-solid.
- It changes colour.
- It changes the taste.
- The change cannot be reversed.
Choose the correct option from below:
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Can you change rust back into iron by some simple method?
Write the chemical reaction of baking soda with lemon.
How would you show that the settling of curd is a chemical change?
The reaction of H2 gas with oxygen gas to form water is an example of ______.
What is thermochemical reactions?
