In recent years the concentration of co2 in the atmosphere has increased to approximately 350 ppm based on mass content. given the approximate composition of air: o2 – 20.36% wt co2 – 0.035% wt n2 – 76.595% wt ar – 0.01% wt h2o – 3.0% wt a) determine the average molecular weight of air. b) determine the composition of air in mol %. c) determine the ppm of co2 based on mole content.

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 increase of protons   hope this

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the answers would be

the first one and the second one