A flexible walled container if inflated to 50.0 liters with a pressure of 6.89 atm at a temperature of 40 degrees Celsius. The temperature of the balloon is decreased to 5.0 Celsius and the pressure is reduced to 1.00 atm. What is the volume in liters of the container? The amount (moles) of gas is constant.

Not sure how to write the formula for this one? Anyone? Thanks.

Use the ideal gas law:


PV = nRT


From the initial data you are given P, V, and T, so you can calculate n (the number of moles of gas). Then you are given new values for P and T, and so using that same value for n you get the new value for V.

Alternatively, realizing that for constant n you have:


\frac {P_1 V_1} {T_1} = \frac {P_2 V_2} {T_2}


You can find the value for V_2 given the data, without actually having to calculate the number of moles of gas.

Remember to convert the temperatiure figures from Celsius to Kelvin.