Prior to their Phaseout in the 1980s, chemicals containing lead were commonly added to gasoline as anti-knocking agents. A 4.083 sample of one such additive containing only lead, carbon, and hydrogen was burned in an oxygen-rich environment. the products of the combustion were 4.444 g of CO2 and 2.274 g of H2O. Insert subscripts to HCPb.
I found the mole of each (C- .1010, H-.0307, and Pb- 0.01370). After dividing by the lowest number I get H-2.22, C-0.1010, and Pb- 0.01370. I am having trouble finding the correct subscripts.
Ms Sue Help me
Help us help you by answering the following.
1. How can the product be ONLY CO2 and H2O. Where is the Pb? And is that Pb, or PbO, PbO2, or Pb3O4? I suspect Pb but I don't know that because you don't list the temperature of the combustion.
2. Post your work for the numbers you have but we must the products first.
However, I will assume Pb is the material.
So 4083 g sample
with 4.444 g CO2
with 2.274 g H2O
with ? g Pb. I get approx 2.6 g Pb but you need a better number than that.
Convert to mols and divide by the smallest number (which will be the mols Pb). Post your work and if you have trouble I can help you through it.
Hint: this is tetraethyl lead.
Do this:
g C = 4.444 x 12/44 = ?
g H = 2.274 x 2/18 = ?
g Pb = 4.083-g C - gH = ?
1. The problem that I listed was the only information supplied- there is no mention of lead as a product, and no combustion temp.
2. g C = (4.444)(12.01)/(44.01) = 1.213 g
g H = (2.274)(2)(1.01) / 18.02 = .255 g
4.083- 1.468 = 2.615 g Pb/207.2 = .01262 mol Pb
.1010 mol C -> 8
.2524 mol H -> 20
.01262 mol Pb -> 1
Is this correct? C8H20Pb
To find the correct subscripts, you need to determine the ratio of each element in the compound. Here's how you can do it:
1. Determine the moles of each element:
In your calculation, you found that the moles of carbon (C) are 0.1010, hydrogen (H) is 2.22, and lead (Pb) is 0.01370.
2. Divide the moles by the lowest value:
Dividing the moles by the lowest value (0.01370), you get C ≈ 7.38, H ≈ 161.93, and Pb ≈ 1.
3. Round the values to the nearest whole number:
Since subscripts need to be whole numbers, round each value to the nearest whole number. In this case, it would be C7H162Pb.
Therefore, the correct subscripts for the compound containing carbon, hydrogen, and lead are C7H162Pb.