Agas is initially at a pressure of 225 kpa and a temperature of 245 k in a container that is 4.5 l. if the gas is compressed to a volume of 2.1 l and the temperature changes to 275 k, what is the new pressure?

Use the ideal gas equation PV=nRT. You can compare before and after using P1V1/n1T1=P2V2/n2T2. Since the number of moles remains constant you can disregard moles from the equation and use pressure, volume and temp. Make sure your pressure is converted to atmospheres, your volume is in liters, and your temperature is in kelvins.

14 moles of oxygen needed to produce 12 moles of H2O.

Explanation:

We are given that balance eqaution

We have to find number of moles of O2 needed  to produce 12 moles of H2O.

From given equation

We can see that

6 moles of   H2O produced by Oxygen =7 moles

1 mole of   H2O produced by Oxygen=moles

12 moles of H2O produced by Oxygen=moles

12 moles of H2O produced by Oxygen=moles

12 moles of H2O produced by Oxygen=14 moles

Hence, 14 moles of oxygen needed to produce 12 moles of H2O.