Advertisements
Advertisements
प्रश्न
A solution of a substance ‘X’ is used for white washing Name the substance ‘X’ and write its formula.
उत्तर
Calcium oxide CaO
APPEARS IN
संबंधित प्रश्न
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
Define catalyst.
MATCH THE COLUMNS
| 1 . `H_2` + `CI_2` `→` 2HCI | a. displacement reaction |
| 2. `2FeCI_3`+ `H_2` `→` `2FeCI_2` +2HCI` | b. addition of an electronegative redical |
| 3. Fe + `CuSO_4` `→``FeSO_4` +Cu` | c. removal of an electronegative redical |
| 4. `2H_2O` +`4NO_2`+`O_2` `→` `4HNO_3` | d.reduction by adding hydrogen |
| 5. 3Fe +`3CI_2` `→` `2FeCI_3` | e.electrolysis of water |
| 6. `FeCI_3`+ 3NaOH `→``Fe(OH)_3``↓`+NaCI | F.double decomposition,precipitation reaction |
| 7.`2H_2O` `→` `2H_2``↑`+`O_2` | e. combination or synthesis reaction |
Write true or false :
Hydrogen sulphide has rotten egg smell .
A chemical equation is a statement that describes a chemical change in terms of
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)
Electron ______ is complete in each hydrogen in a hydrogen molecule.
Give an example of a reaction where the following are involved
Electricity
Give reason for the following:
Colourless concentrated sulphuric acid in a test tube changes to blue on adding a small piece of copper to it.
When hydrogen burns in oxygen, water is formed; when electricity is passed through water, hydrogen and oxygen are given out. Name the type of chemical change involved in the two cases.
What is a chemical change? Give two examples of chemical change?
Give a chemical test to distinguish between the following gases.
HCl and H2S
What do you observe when dilute sulphuric acid is added to the following:
Sodium Sulphide
Give a word equation for the following reaction.
An exothermic reaction where both the reactants are gases, one of which is oxygen.
Give reason for the following:
Even though rusting is an exothermic reaction, the heat evolved when an iron nail rusts is unnoticeable.
Complete the table given below.
| Heat on iodine crystals | Colour of vapours evolved |
Complete the table given below.
| Heat on Zinc nitrate | Colour of residue |
Complete the table given below.
| Addition of dil. H2SO4 to FeS | Odour of gas evolved |
Complete the table given below.
| Heat on sodium chloride | Colour imparted to flame during flame test |
State the following reaction represent oxidation or reduction.
\[\ce{Cu++->Cu}\]
Give a balanced equation for the conversion of an ammonium salt to a basic gas.
Differentiate between the following:
Neutralization reaction and a precipitation reaction.
What kind of a change is associated with decaying of a plants?
Higher order Thinking question
Peeled and unpeeled banana does not look the same. Does that mean peeling banana is a chemical change?
Burning of paper is the best example of ______ change.
Heat may evolve or be absorbed during a ______ change.
Give an example where heat, light, and sound are produced during a chemical change.
Write five changes in the characteristics of a substance that can take place during a chemical change.
Write the characteristics of chemical change.
Collect information about the types of fuels used for cooking in your area. Discuss with your teachers/parents/others which fuels are less polluting and why.
