In the compound (NH4)2S2O3, which element is present in the largest percent by mass?  Data sheet and Periodic Table

A 10 gram sample of which substance contains the greatest number of hydrogen atoms?   Data sheet and Periodic Table

In a 10.0 L vessel at 100.0 oC, 10.0 grams of an unknown gas exert a pressure of 1.13 atm.   What is the gas? Data sheet and Periodic Table

Which gas, helium or argon, effuses faster under the same conditions and by how much? Data sheet and Periodic Table         

Which calculation can be used to determine the standard enthalpy of formation of NO(g)?N2(g) + 2O2(g)2NO2(g)              ΔH°1NO(g) + ½O2(g)NO2(g)              ΔH°2   Data sheet and Periodic Table

Which is the best Lewis structure for nitrogen monoxide?  Data sheet and Periodic Table

What is the formal charge on nitrogen in the nitrate ion?           Data sheet and Periodic Table

What is the atomic number of an ion with a –2 charge when it has 18 electrons?   Data sheet and Periodic Table

How many valence electrons are in one acetate ion, CH3COO–?  Data sheet and Periodic Table

In the compound (NH4)2S2O3, which element is present in the largest percent by mass?  Data sheet and Periodic Table