Acetylene, C2H2, burns completely in O2 to produce CO2 and H2O. 2 C2H2 + 5 O2 4 CO2 + 2 H2O If 8.30 mole of C2H2 are completely burned in excess oxygen, the number of moles of CO2 produced is A) 4.00 mol. B) 8.33 mol. C) 12.5 mol. D) 16.6 mol.

na2co3

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6