How to solve limiting reagent problem set?

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Can someone please explain to me how to do question 1,2 and 3? Thanks!

1 Answer
Dec 8, 2017

#1.6xx10^9" g H"_2"O"# are required to process the #"CO"_2# from one day's electrical production.

#3.4xx10^10" g O"_2"# are produced in the process.

#2.9xx10^10" g C"_6"H"_10"O"_5"# are produced.

All answers are rounded to two significant figures.

Explanation:

The basic process will be to first determine the moles and then determine the mass.

#"mol A"="mass A"xx("mol A")/("molar mass A")#
#color(white)(..................................)##uarr#
#color(white)(..................)# (Look up online or calculate).

Convert mol A to mol B using the mol A: mol B ratio from the balanced equation.

#"mol B"="mol A"xx("mol B")/("mol A")#

Then determine the mass from the moles.

#"mass B"="moles B"xx("molar mass B")/("mol B")#

The entire question is:

The Kingston Steam Plant burns 14,000 tons of coal each day and generates 1010 kilowatts-hours of electricity each year (enough for 700,000 homes). Coal is primarily carbon which undergoes combustion in the following reaction:

#"C(s) + O"_2("g")##rarr##"CO"_2("g")#

Since #"O"_2# in the atmosphere is in excess, the coal, #"C"#, is the limiting reagent.

Part 1: Asked and answered in another question.

1. How many grams of oxygen are required for the combustion of 1 day's coal?

#1.06xx10^9color(red)cancel(color(black)("mol O"_2))xx(31.998"g O"_2)/(1color(red)cancel(color(black)("mol O"_2)))=color(blue)(3.4xx"10"^10" g O"_2"#

2. How much carbon dioxide is produced each day?

#1.06xx10^9color(red)cancel(color(black)("mol C"))xx(1"mol CO"_2)/(1color(red)cancel(color(black)("mol C")))=1.06xx"10"^9" mol CO"_2"#

#1.06xx10^9color(red)cancel(color(black)("mol CO"_2))xx(44.009"g CO"_2)/(1color(red)cancel(color(black)("mol O"_2)))=color(blue)(4.7xx"10"^10" g CO"_2"#

This is where your question starts.

Part 2:

#"CO"_2# is removed from the atmosphere by trees and converted into cellulose, #("C"_6"H"_10"O"_5")"_n"#.

The basic reaction for this is:

#"6CO"_2("g") + "5H"_2"O(l)"##rarr##"C"_6"H"_10"O"_5("s") + "6O"_2("g")"#

#"1"#. How many grams of water are required to process the #"CO"_2"# from one day's electrical production at the Kingston Steam Plant?

#1.06xx10^9color(red)cancel(color(black)("mol CO"_2))xx(5"mol H"_2"O")/(6color(red)cancel(color(black)("mol CO"_2)))=8.83xx"10"^8" mol H"_2"O"#

#8.83xx10^8color(red)cancel(color(black)("mol H"_2"O"))xx(18.015"g H"_2"O")/(1color(red)cancel(color(black)("mol H"_2"O")))=color(red)(1.6xx"10"^10" g H"_2"O"#

#"2"#. How much oxygen is produced by this process?

#1.06xx10^9color(red)cancel(color(black)("mol CO"_2))xx(color(red)cancel(color(black)(6))^1"mol O"_2)/(color(red)cancel(color(black)(6))^1color(red)cancel(color(black)("mol CO"_2)))=1.06xx10^9" mol O"_2"#

#1.06xx10^9color(red)cancel(color(black)("mol O"_2))xx(31.998"g O"_2)/(1color(red)cancel(color(black)("mol O"_2)))=color(red)(3.4xx10^10" g O"_2"#

#"3"#. How much cellulose is produced? Molar mass: #"162.141 g/mol"#

#8.83xx10^8color(red)cancel(color(black)("mol H"_2"O"))xx(1"mol C"_6"H"_10"O"_5)/(5color(red)cancel(color(black)("mol H"_2"O")))=1.77xx10^8" mol C"_6"H"_10"O"_5"#

#1.77xx10^8color(red)cancel(color(black)("mol C"_6"H"_10"O"_5))xx(162.141"g C"_6"H"_10"O"_5)/(1color(red)cancel(color(black)("mol C"_6"H"_10"O"_5)))=color(red)(2.9xx10^10" g C"_6"H"_10"O"_5"#