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प्रश्न
Select the correct answer for the following options:
The black residue obtained on heating copper carbonate.
पर्याय
Hydrogen
Copper [II] oxide
Oxygen
Copper [II] hydroxide
Ammonia
उत्तर
Copper [II] oxide
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
heat.
Complete and balance the following chemical equations
Na + H2 O →
What are the characteristics of a chemical reaction ? A chemical reaction is characterised by an irreversible change in which a new substance is formed.
Fill in the blank:
The substances which undergo chemical change are called _______
Fill in the blank:
In some chemical reactions an insoluble ________ is formed when two solutions are mixed.
Balancing a chemical equation is based on
State four conditions necessary for a chemical reaction to take place.
Balance the following equation :
Fe + H2O → Fe3O4 + H2
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
The spoiling of food is a chemical change which is recognized from the generation of certain ______ due to it.
Complete and balance the following reaction:
\[\ce{CuCO3 ->[\Delta]}\]
Name: A brown gas
What do you observe when H2S is passed through a lead nitrate solution.
Select the correct answer for the following options:
The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
Give a word equation for the following reaction.
A salt which reacts with ammonium hydroxide to give a reddish brown precipitate.
What is a chemical 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 hydrochloric acid to silver nitrate.
State the following reaction represent oxidation or reduction.
\[\ce{Fe++->Fe+++}\]
Select the correct answer from the options given below:
State the gaseous product formed, when
An active metal reacts with dilute sulphuric acid.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Copper nitrate.
The chemical change is ______.
Limestone contains ______ mainly.
A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?
Silver articles turning black: ______:: Boiling of H2O: physical change ______.
Burning of paper is the best example of ______ change.
______ is a natural indicator.
On heating calcium carbonate gets converted into calcium oxide and carbon dioxide.
(a) Is this a physical or a chemical change?
(b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved.
Vanaspati is obtained from vegetable oils by the addition of ______ to the oils.
Match the following:
| Column I | Column II | ||
| 1. | Burning of coal | a. | Rusting |
| 2. | Painting of a surface | b. | Evaporation |
| 3. | Dipping iron in the water | c. | Chemical change |
| 4. | Salt from seawater | d. | Prevention of rusting |
What is thermochemical reactions?
