For the following ion, write two valid Lewis structures which are NOT resonance structures, and state which one is a better Lewis structure based on formal charges: NO2

For the reaction of:  3H2(g) + N2(g) 

A 75.5 gram sample of an unknown metal at 95.0oC is placed in 125 gram of water at 25.0oC. If the final temperature of the metal and water is 33.0oC, what is the specific heat capacity of the metal?  (the specific heat of water is 4.184 J/goC). Show all your work for full credit. Use the correct number of significant figures.

An open flask sitting in a lab bench looks empty, but it is actually filled with a mixture of gases called air. If the flask volume is 3.00 L, and the air is at standard temperature and pressure, how many gaseous molecules does the flask contain ?

For the following ion, write two valid Lewis structures which are NOT resonance structures, and state which one is a better Lewis structure based on formal charges: NO3

An antacid tablet contains NaHCO3. What mass of this compound is required to neutralize 75.0 mL of 2.75 M HCl? NaHCO3(aq) + HCl(aq) → NaCl(aq) + CO2(g) + H2O(l)

If 7.78 g of CuSO4 (molar mass 159.61 g/mol) is dissolved in water to make a 0.250 M solution of CuSO4, what is the volume of the solution in milliliters? Show all your work for full credit. Use the correct number of significant figures.

What is the final volume of a sample of gas initially occupying 2.50 L at 9.0oC and 1.25 atm pressure after its pressure is increased to 3.75 atm and its temperature is increases to 78.0oC?

For the following ion, write two valid Lewis structures which are not resonance structures, and state which one is a better Lewis structure based on formal charges: CO32

Use the following enthalpies of formations (∆Hof): CH4(g) HCN(g) NH3(g) ∆Hof -74.6 kJ/mol 135.5 kJ/mol -45.9 kJ/mol to calculate the standard enthalpy of reaction (∆Horxn) for the following reaction: CH4(g) + N2(g) → HCN(g) + NH3(g) ∆Horxn = ?