SSLC (English Medium) Class 9 - Tamil Nadu Board of Secondary Education Question Bank Solutions for Science

What are the effects of carbon dioxide in the atmosphere?

How is carbon dioxide returned to the atmosphere? 

You can see your image in polished floors, but not in wooden table because ______.

Clouds float in atmosphere because of their low ______.

What is meant by atmospheric pressure?

We can create enlarged, virtual images with ______.

State whether true or false. If false, correct the statement.

A compound cannot be broken into simpler substances chemically.

State whether true or false. If false, correct the statement.

Aspirin is composed of 60% Carbon, 4.5% Hydrogen and 35.5% Oxygen by mass. Aspirin is a mixture.

Write down the names of the particles represented by the following symbols and explain the meaning of superscript and subscript numbers attached.

`""_1"H"^1`, `""_0"n"^1`,`""_(-1)"e"^0`

Considering MgCl₂ as ionic compound and CH₄ as covalent compound give any two differences between these two compounds.

List two differences between the properties exhibited by covalent compounds and ionic compounds.

Give an example for each of the following statement

A compound in which two Covalent bonds are formed. 

Give an example for each of the following statement.

Formation of coordinate covalent bond between NH₃ ➝ BF₃ molecules

Give an example for each of the following statement.

A compound in which three covalent bonds are formed.

Identify the incorrect statement and correct them.

1. Like covalent compounds, coordinate compounds also contain charged particles (ions). So they are good conductors of electricity. 
2. Ionic bond is a weak bond when compared to Hydrogen bond.
3. Ionic or electrovalent bonds are formed by mutual sharing of electrons between atoms. 
4. Loss of electrons is called Oxidation and gain of electron is called Reduction.
5. The electrons which are not involved in bonding are called valence electrons.

Discuss in brief about the properties of coordinate covalent compounds.

What are the various uses of Aquaregia.

Define aquaregia.

A phenomenon in which an element exists in different modification in same physical state is called ______.

Carbon forms large number of organic compounds due to ______.