# A student dissolves two moles of Mg(NO3)2 into a beaker of water. How many nitrate ions are present in the solution?

A student dissolves two moles of Mg(NO3)2 into a beaker of water. How many nitrate ions are present in the solution?A system takes in 150 kJ of heat and does 230 kJ of work. The change in the internal energy of the system is:A student obtains a 2.50 liter balloon 312 K and 0.922 atm. She cools the balloon to 280 K. The volume of the balloon at 280 K is:A sample of Ar (g) is observed to effuse through a porous barrier in 1.72 minutes. Under the same conditions, the same number of moles of an unknown gas requires 1.44 minutes to effuse through the same barrier. Which of the following is the unknown gas? A student obtains a 8034.5 liter weather balloon that contains 6054 grams of neon gas at 202 K. The pressure inside the weather balloon is:A student combusts 504.96 grams of ethene gas, C2H4. How many liters of CO2 (g) are produced at a pressure of 0.993 atm and a temperature of 295 K? C2H4 (g) + 3 O2 (g) 2 CO2 (g) + 2 H2O (g) 