Advertisements
Advertisements
प्रश्न
Define the following term of Atom .
Advertisements
उत्तर
Atom — An atom is the smallest part of an element that takes place in a chemical reaction.
APPEARS IN
संबंधित प्रश्न
The inter-molecular space is maximum in
The molecules can move freely anywhere in
Differentiate between an atom and a molecule.
Fill in the blank
Any matter which has a definite _______ but no definite shape is called a _______
What is meant by saying that metals are sonorous ?
Name two solid, two liquid and two gaseous elements at the room temperature.
Which of the following is not an element ?
Which one of the following is not a metalloid ?
There are three substances X, Y and Z. The substance X does not have a fixed melting point or boiling point and it still shows the individual properties of its constituents. The substance Y is a pure substance which occurs in nature as such. The substance Y has a fixed melting point and boiling point but it cannot be broken down into simpler substances by any chemical means. The substance Z is also a pure substance whose properties are entirely different from those of its constituents. The substance Z can, however, be divided by electrolysis into two substances which belong to the same class of substances as Y.
- What type of substance could X be ? Name one substance like X.
- What type of substance could Y be ? Name one substance like Y.
- What type of substance could Z be ? Name one substance like Z.
- Which process involves absorption or release of an appreciable amount of energy : formation of substance X or formation of substance Z ?
- Name the three groups into which all the substances like Y are divided on the basis of their properties.
A solution contains 5.6 mL of alcohol mixed with 75 mL of water. Calculate the concentration of this solution.
Classify the following into true solutions and colloidal solutions:
Ink, Salt solution, Starch solution, Blood, Sugar solution
Define Foam Give one example.
One of the following liquids will leave behind a residue on heating. This one is :
How will you separate a mixture of common salt, sulphur powder and sand ?
Write a few lines on the blackboard with a chalk. Now observe the chalk. What changes do you see in the chalk?
A standard sheet of paper is about ______ of atoms thick
Give some examples of the Tyndall effect observed in your surroundings?
Complete the following table:
| S.No. | CELSIUS | KELVIN |
| 1. | 90°C | 363 K |
| 2. | ______ | 283 K |
| 3. | 63 °C | ______ |
| 4. | 250°C | ______ |
| 5. | ______ | 303 K |
A teabag placed in a cup of hot water will diffuse into the water.
