Advertisements
Advertisements
प्रश्न
Name the following:
The type of change physical or chemical involved – ‘during respiration in human beings’.
उत्तर
Chemical Change.
APPEARS IN
संबंधित प्रश्न
Changes in which new substances are formed are called ______ changes.
Write the missing reactants and products and balance the equations.
NaOH + ............... `→` NaCI + ...................
Give reason.
Acidic soil is treated with quick lime.
What are homogenous reactions ?
Fill in the blank:
During a chemical reaction transfer of ________ takes place.
Write true or false .
A black residue is formed when sugar is heated .
Name the type of chemical reaction shown by the following equation :
Fe2O3 + 2Al → Al2O3 + 2Fe
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Sodium chloride
What is a chemical reaction?
Give an example of a reaction where the following are involved:
Solution
Give an example of a reaction where the following are involved
Catalyst
What do you understand by precipitation reaction? Explain with examples.
What do you observe? When
Water is added to the quick lime.
Complete and balance the following reaction:
\[\ce{Pb(NO3)2 ->[\Delta]}\]
Give a chemical test to distinguish between the following gases.
H2 and O2
Distinguish by heating the following in dry test tubs.
Copper Sulphate and copper carbonate
Give a word equation for the following reaction.
A salt which reacts with ammonium hydroxide to give a reddish brown precipitate.
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.
Match the chemical reactions in List I with the appropriate answer in List II.
| List I | List II | ||
| 1. | \[\ce{XY⇌[heat]X + Y}\] | A: | Displacement reaction |
| 2. | \[\ce{XY->X + Y}\] | B: | Double decomposition |
| 3. | \[\ce{X+Y- + A+B^-->X+B- + A+Y-}\] | C: | Endothermic reaction |
| 4. | \[\ce{X + YZ->XZ + Y}\] | D: | Thermal dissociation |
| 5. | \[\ce{X + Y->[heat]XY -\Delta}\] | E: | Decomposition reaction |
State the following reaction represent oxidation or reduction.
\[\ce{Cu++->Cu}\]
State the following reaction represent oxidation or reduction.
\[\ce{H->H+}\]
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Copper nitrate.
Match the following:
| 1. | Sodium Chloride | a. | CaSO41/2H2O |
| 2. | Calcium sulphate dihydrate | b. | C2H5Oh |
| 3. | Magnesium sulphate hydrate | c. | CaSO4.2H2O |
| 4. | Calcium sulphate hemihydrate | d. | NaCl |
| 5. | Phenol | e. | MgSO4.H2O |
Analogy:
H2O: Water:: NaCl: ______.
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
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?
The chemical formula of rust is ______.
______ is the chemical name of slaked lime.
