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प्रश्न
Name the element in the compound and give the formula of the following compound:
Blue vitriol
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उत्तर
| Element | Element in compound | Formula |
| Blue vitriol | Copper, sulphur, oxygen, hydrogen | CuSO4.5H2O |
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संबंधित प्रश्न
An element X of valency 3 combines with another element Y of valency 2. What will be the formula of the compound formed ?
Give the formulae of the compounds formed from the following sets of elements :
- calcium and fluorine
- hydrogen and sulphur
- nitrogen and hydrogen
- carbon and chlorine
- sodium and oxygen
- carbon and oxygen
(a) Write the symbols/formulae of two simple ions and two compound ions (or polyatomic ions).
Define ‘formula unit’ of an ionic compound. What is the formula unit of (i) sodium chloride, and
(ii) magnesium chloride ?
Correct the following statement:
A molecular formula represents an element.
Identify the following substance:
Gas C that is colourless and can be used as a bleaching agent.
Identify the following substance:
A brown gas D with the irritating smell.
Write the formula of the following compound:
Potassium dichromate
Write the formula of the following compound:
Sodium carbonate
Write the formula of the following compound:
Sodium aluminate
Write the formula of the following compound:
Calcium bisulphite
Write the formula of the following compound:
Zinc nitrate
Write the formula of the following compound:
Copper [II] oxide
Write the formula of the following compound:
Copper [I] sulphide
Write the formula of the following compound:
Iron [II] chloride
Write the formula of the following compound:
Lead [II] hydroxide
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
Mg(SO4)2
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 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.
