A. True. The ozone layer is very critical to our health.
hard because it has calcium and magnesium
This is a combined gas law problem, according to which

where P is the pressure of the gas, V is the volume of the gas, and T is the temperature of the gas, and the subscripts 1 and 2 correspond to the initial and final conditions of the gas. In this problem, we are given the initial pressure, volume, and temperature of the gas in the balloon:
P₁ = 1.0 atm
V₁ = 1.8 L
T₁ = 295.15 K (K = °C + 273.15).
Moreover, we are given the final pressure and temperature of the gas in the balloon.
P₂ = 0.86 atm
T₂ = 281.15 K.
What we want to find is the final volume, V₂, which we can obtain by rearranging the combined gas equation to solve for V₂:

This answer has three significant figures. However, the question as written would warrant an answer that comprises one significant figure (as 8 °C has only one sig fig). In that case, the answer would be 2 L. If the answer is to be given to two significant figures, the volume would then be 2.0 L.
Answer:
4.78atm
Explanation:
From the question, we obtained the following:
P1 (initial pressure) = 3.5 atm
T1 (initial temperature) = 200K
T2 (final temperature) = 273K
P2 (final pressure) =?
Using P1/T1 = P2/T2, the final pressure can be obtained as shown below:
P1/T1 = P2/T2
3.5/200 = P2/273
Cross multiply to express in linear form as shown below:
200 x P2 = 3.5 x 273
Divide both side by 200
P2 = (3.5 x 273)/200
P2 = 4.78atm
Therefore, the pressure at 273K is 4.78atm