QUESTIONS
VERY SHORT QUESTIONS
1. Write different states of matter.
2. Which has more density-liquid or solid?
3. What is the melting point ofice?
4. Boiling point of alcohol is 78°C. Change it into Kelvin seale?
5. Why do gas exert pressure?
6. How do we liquefy the gases?
7. What happens to particles when salt dissolves in water?
8 What is the physical state of water:
(a) at 0°C
(b) 25°C
9. What is the chemical name of dry ice?
10. Why is heat energy needed to melt a solid?
SHORT QUESTIONS
Classify the matter on the basis of physical characteristics
Answers
Answer:
1:solid, liquid,gas
2:solid
short questions one also Same answer as 1
Answer:
Hope it helps u , my friend :)
Very short questions:-
1) There are three natural states of matter: Solids, liquids, gases.
2) solid
3) 0 degree Celcius or 32 degree Fahrenheit
4) 351 K is the Kelvin scale temperature of the ethyl alcohol.
Solution:
Boiling point of the given alcohol = 78°C
Kelvin scale temperature = Celsius scale temperature + 273
Kelvin scale Temperature = 78 + 273
= 351 K
Hence, temperature of 78°C on Celsius scale is equal to 351 K on the Kelvin scale.
Kelvin scale of temperature is invented by “Lord William Thomson Kelvin”. It is used only for research work by the scientist. For measuring temperature, Kelvin is the SI unit. K is the symbol used for representing Kelvin. Kelvin scale and Celsius scale of temperature has a relationship and is written as,
Temperature on Kelvin scale = Temperature on Celsius scale + 273
5) Gas pressure is caused by the force exerted by gas molecules colliding with the surfaces of objects . Although the force of each collision is very small, any surface of appreciable area experiences a large number of collisions in a short time, which can result in a high pressure.
6) Liquefaction of gases is the process by which substances in their gaseous state are converted to the liquid state. When pressure on a gas is increased, its molecules closer together, and its temperature is reduced, which removes enough energy to make it change from the gaseous to the liquid state.
7) Water molecules pull the sodium and chloride ions apart, breaking the ionic bond that held them together. After the salt compounds are pulled apart, the sodium and chloride atoms are surrounded by water molecules, as this diagram shows. Once this happens, the salt is dissolved, resulting in a homogeneous solution.
8) liquid
(a) 25°C, the physical state of water is a liquid. (b) 0°C, the physical state of water can be either a solid or a liquid.
9) carbon dioxide
10) Heat Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart so that the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature.
Short Questions :-
1) Classification- On the basis of physical properties, matter is classified as solids, liquids and gases. On the basis of chemical properties, matter is classified as elements, compounds and mixtures. ... Gases- Gases have weak intermolecular flow, high compressibility, and no definite shape and volume.