Before a trip from New York to Boston, the pressure in the automobile tire is 2.1 atm at 280 K. At the end of the trip, the pressure gauge reads 1.88 atm. What is the new Celsius temperature of the air inside the tire?(Assume tires with constant volume).

This is how I did it: I used P1/T1-P2/T2. So I did (1.8)(280) which equals into 504, then I divided that by 2.1, which made 240, & then I subtracted 273 to make it into Celcius and got -33. That way was wrong so I did the problem again but this time I subtracted 273 from 280 first, & I got 7. Then, I multiplied 7 & 1.8 which made 12.6. I divided 12.6 by 2.1, & I ended up getting 6. This was wrong too. So, how am I suppose to solve it?

To solve this problem correctly, you need to use the ideal gas law equation, which relates pressure, volume, temperature, and the ideal gas constant (R).

The ideal gas law equation is expressed as follows:
PV = nRT

Where:
P is the pressure
V is the volume
n is the number of moles
R is the ideal gas constant
T is the temperature

In your question, the volume remains constant, so the equation simplifies to:
P1/T1 = P2/T2

Let's use this equation to solve the problem step by step:

Step 1: Convert the initial pressure to atm.
The initial pressure is given as 2.1 atm, so we don't need to convert it.

Step 2: Convert the initial temperature from Kelvin to Celsius.
The initial temperature is given as 280 K. To convert it to Celsius, subtract 273.15.
280 K - 273.15 = 6.85 °C

Step 3: Convert the final pressure to atm.
The final pressure is given as 1.88 atm, so we don't need to convert it.

Step 4: Use the equation P1/T1 = P2/T2 to find the new temperature in Celsius.
Substitute the values you have into the equation:
2.1 atm / 6.85 °C = 1.88 atm / T2

To solve for T2, cross multiply and rearrange the equation:
2.1 atm * T2 = 1.88 atm * 6.85 °C

T2 = (1.88 atm * 6.85 °C) / 2.1 atm
T2 = 6.12 °C

So, the new Celsius temperature of the air inside the tire is approximately 6.12 °C.