Consider the unbalanced equation for the combustion of hexane:
2c6h14(g)+19o2(g)→12co2(g)+14h2o(g) determine how many moles of o2 are required to react completely with 7.9 moles c6h14.

The balanced equation is C6H14(g) + 19/2O2(g) → 6CO2(g) + 7H2O(g). If you are given 7.9 moles C6H14, multiply it by a ratio of 19/2/1 to get the moles of oxygen. Then, you will get 75.05 moles of O2.

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

the temperature of the gas, in k, not celsius.