How would an increase in pressure and decrease in temperature of a gas effect?
(a)- The distance between particles
(b)- The physical state of the gas
(c)- The strength of the force of attraction between particles
Write the chemical formula of dry ice. How is it stored? Explain why it is named.

Hint: As the pressure of the gas is increased and the temperature is decreased, the molecules will come closer to each other. There are three physical states of a substance namely gas (molecules are very far from each other), liquid (molecules are not so far and not so close to each other), and solid (molecules are very close to each other). Solid form of carbon dioxide is known as dry ice.

Complete step by step answer:
As the temperature of the gas is decreased and the pressure of the gas is increased there will be significant changes in the gas.

(a)- The distance between particles.
As the temperature of the gas is decreased and the pressure of the gas has increased the molecules of the gas will come closer to each other and the distance between the molecules will decrease.

(b)- The physical state of the gas
Since on increasing the pressure and decreasing the temperature, the molecules come closer to each other which means that the gas form will convert into liquid form and on further increasing the condition it will convert into a solid form.

(c)- The strength of the force of attraction between particles
Since the molecules are coming closer to each other, the force of attraction between the molecules will increase.
The solid form of carbon dioxide is known as Dry ice so its chemical formula is $C{{O}_{2}}$. Dry ice is subjected to sublime i.e., the solid form is directly converted into gas form. So it has to be stored in an insulated container. It is named dry ice because of its sublimation property, it doesn't convert into liquid instead the solid directly converts into gas.

Note: Dry ice should be used properly because long exposure to dry ice can cause many serious health issues and skin problems. Mainly the dry ice is used to cool the substance at a very high speed.