Need help with all questions Ammonia fumes can permanently log soft contact lens

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Need help with all questions Ammonia fumes can permanently log soft contact lenses. Briefly explain why students wearing soft contact lenses should be particularly careful when doing this experiment. Will wearing goggles or other eye protection remove the hazard for these students? Briefly explain. The formula of a compound of lead (Pb) and sulfur (S) was determined using the method in this module. A sample of Pb was weighed into a crucible and covered with finely powdered S. The crucible was covered and heated to allow the Pb and S to react. Additional heating burned off all unreacted S. The crucible was then cooled and wighed. The following data were collected Calculate the mass of Pb reacted. Calculate the mass of compound that formed. Calculate the mass of S reacted. Calculate the number of moles of Pb reacted. Calculate the number of moles of S reacted. Find the simplest whole-number ratio of the number of moles of Pb to the number of moles of S in the compound formed. Write the empirical form

Explanation / Answer

I'll help you with question 2 that requires calculus.

1. and 4. Mass and number of moles of Pb reacted:

Assuming the first law of mass conservation then:

Mass of Pb reacted = mass of crucible, cover, Pb - mass of crucible, cover

Mass of Pb reacted = 32.025 - 27.889 = 4.136 g of Pb

moles of Pb = mass/atomic weight = 4.136 / 207.2 = 0.01996 moles of Pb.

2. Mass of product formed:

Mass of Product = Mass Crucible, cover and product - massCrucible, Cover

Mass of Product = 32.666 - 27.889 = 4.777 g of Product formed

3. and 5. Mass and moles of S reacted:

Mass of S = mass crucible, cover and product - mass of crucible, cover and Pb

Mass of S = 32.666 - 32.025 = 0.641 g of S

moles of S = 0.641 / 32 = 0.02 moles of S

6. With the previous results of the number of moles, we can see that the number of moles of Pb and S, are practically the same (0.01996 and 0.02), so a simpliest ratio would be 1 and 1. We can determine that number by this:

Pb = 4.136/207.2 = 0.01996 moles /0.01996 = 1

S = 0.641/32 = 0.02 moles / 0.01996 = 1.002 or simply 1.

7. the previous numbers obtained give us the number of atoms of each component in the formula so:

Empiric Formula = PbS

Another way to obtain it with the mass:

% Pb = (4.136/4.777) x 100 = 86.58% / 207.2 = 0.4179 / 0.4179 = 1

%S = 100 - 86.58 = 13.42% / 32 = 0.4194 / 0.4179 = 1.004 = 1

Empiric Formula = PbS

Question 1 and 3, Post it in a new question (both of them separate) and I'll gladly answer it for you.

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