Advertisements
Advertisements
प्रश्न
Balancing a chemical equation is based on
पर्याय
Law of conservation of mass
Mass of reactants and products
Symbols and formulae
None of the above
Advertisements
उत्तर
Law of conservation of mass.
APPEARS IN
संबंधित प्रश्न
Changes in which new substances are formed are called ______ changes.
What do you observe when iron nail is kept in copper sulphate solution for sometime.
What are the characteristics of a chemical reaction ? A chemical reaction is characterised by an irreversible change in which a new substance is formed.
Name the type of chemical reaction shown by the following equation:
2Mg + O2 → 2MgO
Give an example of a reaction where the following are involved
Light
Name: Two carbonates do not produce carbon dioxide on heating.
Name: A brown gas
What do you observe when dilute sulphuric acid is added to the following:
Sodium Sulphide
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.
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
A coloured substance which leaves on strong heating a black residue and evolves two colourless gases one of which is acidic and the other neutral.
Give balanced equation for the following conversion affected by heat alone on the substance:
Copper nitrate to nitrogen dioxide
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 |
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Copper nitrate.
______ gas causes tears in our eyes while cutting onions.
Classify the following as physical or chemical properties
Most metal oxides form alkalis on interacting with water.
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 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.
Chemical changes are important in our day-to-day life. Give examples.
