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प्रश्न
Write the formula of the following compound:
Iron [III] sulphide
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उत्तर
Iron [III] sulphide - Fe2S3 - `"Fe"^(3+)"S"^(2-)`
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संबंधित प्रश्न
What is meant by the term chemical formula?
What do the following abbreviations stand for ?
- O
- 2O
- O2
- 3O2
Name the elements water is made of. What are the valencies of these elements ? Work out the chemical
formula for water.
An element Y has a valency of 4. Write the formula for its :
- chloride
- oxide
- sulphate
- carbonate
- nitrate
Identify the following substance:
An alkaline gas A which gives dense white fumes with hydrogen chloride.
XCl2 is the chloride of a metal X. State the formula of the sulphate and the hydroxide of the metal X.
Write the formula of the following compound:
Potassium sulphate
Write the formula of the following compound:
Sodium zincate
Write the formula of the following compound:
Sodium sulphate
Write the formula of the following compound:
Sodium nitrite
Write the formula of the following compound:
Aluminium hydroxide
Write the formula of the following compound:
Copper [I] chloride
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
(NH4)3SO4
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
NaCO3
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
Ca2(PO4)3
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
Mg(SO4)2
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
KNO3
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
BaCl2
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.
