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प्रश्न
Balancing a chemical equation is based on
विकल्प
Law of conservation of mass
Mass of reactants and products
Symbols and formulae
None of the above
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उत्तर
Law of conservation of mass.
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संबंधित प्रश्न
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Which one of the following alters the rate of the chemical reaction without itself undergoing any change?
- temperature and Pressure
- concentration of reactants
- presence of catalyst
- none of these
What are homogenous reactions ?
What are the characteristics of a chemical reaction ? A chemical reaction is characterised by an irreversible change in which a new substance is formed.
State what you would observe when the following substance is heated in a glass test tube red lead.
What is the reaction called when oxidation and reduction take place simultaneously? Explain with one example.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Water
Give reason for the following:
Molybdenum is used in the manufacture of ammonia.
What do you understand by precipitation reaction? Explain with examples.
Complete and balance the following reaction:
\[\ce{CuCO3 ->[\Delta]}\]
Complete and balance the following reaction:
\[\ce{NH3 + O2 ->[\Delta]}\]
Write your observation and a balanced equation in the case of the following substances being heated.
Ammonium dichromate.
Complete the table given below.
| Addition of dil. H2SO4 to zinc | Test for gas evolved |
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Lead nitrate.
_____ is the basic material to manufacture urea.
A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?
Classify the following as physical or chemical properties
Zinc dissolves in hydrochloric acid with the evolution of hydrogen gas.
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.
Write word equations for two chemical reactions with the help of materials given in the box.
| Air, copper sulphate, iron, vinegar, iron oxide, carbon dioxide, iron sulphate, copper, lime water, water |
Chemical changes are important in our day-to-day life. Give examples.
