Advertisements
Advertisements
प्रश्न
Why are the symbols and formulae of substances important?
Advertisements
उत्तर
Importance of symbols and Formulae:
Symbols and formulae of substance gives a lot of information like.
1. Types of elements present in the compound. E.g. (H20 is made of two elements hydrogen and oxygen).
2. Number of each kind of atoms in one molecule. E.g. (water has 2 atoms of hydrogen combined with 1 atom of oxygen.)
3. Mass of one molecule of the compound. E.g. [H2O has mass (1 × 2) + 16 = 18 g].
APPEARS IN
संबंधित प्रश्न
Write down the name of a compound represented by the following formula:
KNO3
Give the name of the element present in the following compound:
Baking powder
Give the name of the element present in the following compound:
Potassium sulphate
Define: Mass number :
Define: Atomic weight :
Write the formulae of the following compounds. Also name the elements present in them.
- Water
- Ammonia
- Methane
- Sulphur dioxide
- Ethanol
In what form does oxygen gas occur in nature ?
In what form do noble gases occur in nature?
What do the following denote ?
- N
- 2N
- N2
- 2N2
One of the forms of a naturally occurring solid compound P is usually used for making the floors of houses. On adding a few drops of dilute hydrochloric acid to P, brisk effervescence are produced. When 50 g of reactant P was heated strongly, than 22 g of a gas Q and 28 g of a solid R were produced as products. Gas Q is the same which produced brisk effervescence on adding dilute HCl to P. Gas Q is said to cause global warming whereas solid R is used for white-washing.
- What is (i) solid P (ii) gas Q, and (iii) solid R.
- What is the total mass of Q and R obtained from 50 g of P ?
- How does the total mass of Q and R formed compare with the mass of P taken ?
- What conclusion do you get from the comparison of masses of products and reactant ?
- Which law of chemical combination is illustrated by the example given in this problem ?
The cation of an element has :
Molecular compounds are usually formed by the combination between :
An element X forms the following compounds with hydrogen, carbon and oxygen :
H2X, CX2, XO2, XO3
State the three valencies of element X which are illustrated by these compounds.
Explain the term – molecules. Give three examples of atoms of the same element forming a molecule. State the atomicity of the same.
State the atomicity of the following:
Chlorine
Define: Atomicity.
Write any two classifications of a molecule.
