The combined gas law states that for a closed system (constant moles of gas), the PV product divided by the absolute temperature is constant or P1V1/T1=P2V2/T2. This page provides problems utilizing this relationship. When you press "New Problem," a question will appear to the right of the table. Determine the value of the answer, enter it in the cell and press "Check Answer." Results appear in the table where running totals are also kept. If you get a problem wrong, you should redo it. Since these are all Combined Law problems, you are to assume that all of the changes are taking place under conditions of constant n.