Question

(a) CO2 is a gas. Write its two gaseous properties to justify it. (b) How can we liquefy a gas ? (c) Solid CO2 is also known as dry ice. Why ?

Answer 1

a) Hmm I'm going to go with it's less dense that a solid or liquid i.e open a bottle of coke and the carbon dioxide bubbles float up and out of the bottle. If it was denser it would be a layer under the liquid 

Or.. 
A gas has no definite shape or volume of its own. It acquires the shape of the container. Intermolecular attraction is the weakest in gases whereas intermolecular separation is the largest. Hence, molecules in a gas move very fast and the gas expands to fill all the space available. 

Cooling changes it into liquid state.
b)  gases are liquefied on low temperatures by applying high pressure.this process is called fractional distillation. all the gases are first compressed and brought into low temperatures, according to their melting point, the wud liquefy. example:- carbon dioxide gas liquefies at -78 degree Celsius
c) Solid CO2 is called dry ice. Because it looks like ice & it is cold like ice. But when it melts it does not becomes as a wet liquid. But when ice melts it forms liquid. This is the reason that solid CO2 is called dry ice.

Answer 2

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