Advertisements
Advertisements
प्रश्न
Identify the following substance:
Gas C that is colourless and can be used as a bleaching agent.
Advertisements
उत्तर
Sulphur dioxide
APPEARS IN
संबंधित प्रश्न
The radius of an oxygen atom is 0.073 nm. What does the symbol ‘nm’ represent ?
Work out the formula for sulphur dioxide. (Valencies : S = 4 ; O = 2)
An element B shows valencies of 4 and 6. Write the formulae of its two oxides.
(a) Write the symbols/formulae of two simple ions and two compound ions (or polyatomic ions).
Name the element in the compound and give the formula of the following compound:
Acetic acid
Name the element in the compound and give the formula of the following compound:
Blue vitriol
Write the formula of the following compound:
Sodium nitrate
Write the formula of the following compound:
Sodium sulphite
Write the formula of the following compound:
Calcium sulphate
Write the formula of the following compound:
Zinc sulphate
Write the formula of the following compound:
Iron [III] sulphide
Write the formula of the following compound:
Diamine silver chloride
Define the term Relative atomic mass. State why indirect methods are utilised to determine the absolute mass of an atom. Explain in brief the indirect method used.
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
Mg(SO4)2
Write the chemical formula for the following elements.
- Hydrogen
- Nitrogen
- Ozone
- Sulphur
Write the molecular formulae for the following compounds
Aluminium (III) nitrate
Write the molecular formulae for the following compounds
Magnesium (II) acetate
Complete the following crossword puzzle (Fig. 3.1) by using the name of the chemical elements. Use the data given in Table.
| Across | Down | ||
| 2 | The element used by Rutherford during his α–scattering experiment | 1 | A white lustrous metal used for making ornaments and which tends to get tarnished black in the presence of moist air |
| 3 | An element which forms rust on exposure to moist air | 4 | Both brass and bronze are alloys of the element |
| 5 | A very reactive non–metal stored under water | 6 | The metal which exists in the liquid state at room temperature |
| 6 | Zinc metal when treated with dilute hydrochloric acid produces a gas of this element which when tested with burning splinter produces a pop sound. | 8 | An element with symbol Pb |
Play a game for writing formula.
Example 1: Make placards with symbols and valencies of the elements separately. Each student should hold two placards, one with the symbol in the right hand and the other with the valency in the left hand. Keeping the symbols in place, students should criss-cross their valencies to form the formula of a compound.
Play a game for writing formula.
Example 2: A low-cost model for writing formulae: Take empty blister packs of medicines. Cut them in groups according to the valency of the element, as shown in the figure. Now, you can make formulae by fixing one type of ion into other.
For example:
The formula for sodium sulphate:
2 sodium ions can be fixed on one sulphate ion.
Hence, the formula will be Na2SO4.
Do it yourself:
Now, write the formula of sodium phosphate.
