How many molecules of hydrogen gas, H 2 , occupy 0.500 L at STP? Strategy Plan STEP

How many molecules of hydrogen gas, H₂, occupy 0.500 L at STP?

Transcribed Image Text:

Strategy Plan STEP 1: What unit is asked for in the answer? STEP 2: What given value is related to the answer? STEP 3: What unit factor(s) should we apply? From the molar volume of a gas at STP, 1 mol H₂ = 22.4 LH₂ and by defini- tion, 1 mol H₂ = 6.02 x 1023 mol- ecules H₂. Thus, the two pairs of unit factors are shown in Step 3. Unit Analysis Map given value 0.500 L H₂ X unit factor 1 1 mol H₂ 22.4 L H₂ Step 1: Step 2: Step 3: molecules H₂ X 1 mol H₂ 22.4 L H₂ 0.500 L H₂ 1 mol H₂ 6.02 x 1023 molecules H₂ or or unit factor 2 6.02 x 1023 molecules H₂ 1 mol H₂ 22.4 L H₂ 1 mol H₂ 6.02 x 1023 molecules H₂ 1 mol H₂ unit in answer = ? molecules H₂