10.0 liters of oxygen are contained in a diver's tank at 20.0°c and 2.0 atm pressure. what is the pressure when the tank is left exposed to the sun and it is heated to 45°c?

The question is asking about the relationship between pressure (p) and temperature (t). So, we do not need to worry about the volume (v). To answer this, add 273 to both temperatures so that they will be in Kelvin. Then use the formula p1/t1=p2/t2. So we would end up with 2.0/293 = ?/318. Use algebra to solve the problem for p2 and you will have the new pressure after the tank has been exposed to the sun, which is 2.170