Question

how is the atmosphere and mass of Venus is different from earth

Answer 1

The atmosphere of Venus is 90 times more dense than that on Earth and it is made of 96.5% of CO2 and a 3% of nitrogen. This means that both planets have the same amount of Nitrogen on their atmospheres. Surprinsingly the CO2 on Earth is stored on calcite type rocks and if we would convert the CO2 on these rocks into atmospheric CO2 it would amount to the same amount of CO2 that there is on Venus' atmosphere.
Because of the denser atmosphere and the chemical composition Venus experiences an inmense green-house effect that raises the temperature over the surface to more than 470ºC.
Green-house effect on Venus The figure on the right illustrates the basics of the..:-D

Answer 2

$\implies$ Earth’s atmosphere is composed of various gases like oxygen, carbon dioxide, nitrogen, water vapour along with various gases in small quantities, hence making it a balanced composition which is more livable than other planets. Planets like Venus and Mars have more than 95% of carbon dioxide in the air making the existence of life impossible.