Register to reply

Calculating alkalinity and expressing it in as CaCO3

by Jim4592
Tags: alkalinity, as caco3, expressing
Share this thread:
Jim4592
#1
Sep20-10, 11:13 PM
P: 49
1. The problem statement, all variables and given/known data
Convert the following from milligrams per liter as the ion to milligrams per liter as CaCO3.

A) 83.00 mg/L Ca2+
B) 27.00 mg/L Mg2+
C) 48.00 mg/L CO2
D) 220.00 mg/L HCO3-
E) 15.00 mg/L CO32-


2. Relevant equations



3. The attempt at a solution
I think I did the calculations correctly, but there's a slight difference between my answer and the book's answer...I was hoping someone could look and see if I did the steps correctly and if so is it difference negligible?

A) (83.00 mg Ca{2+} / L) x (1 mmole Ca{2+} / 40.078 g) x (2 meq Ca{2+} / mmole Ca{2+}) x (100 mg CaCO3 / 2 meq) = 207.096 mg/L as CaCO3, book answer = 207.25

B) (27.00 mg Mg{2+} / L) x (1 mole Mg{2+} / 24.305 g) x (2 meq Mg{2+} / mmole Mg{2+}) x (100 mg CaCO3 / 2 meq) = 111.088 mg/L as CaCO3, book answer = 111.20

C) (48.00 mg CO2 / L) x (1 mmole CO2 / 44.0095 g) x (2 meq CO2 / 1 mmole) x (100 mg CaCO3 / 2 meq) = 109.067 mg/L as CaCO3, book answer = 109.18

D) (220 mg HCO3{-} / L) x (1 mmole HCO3{-} / 61.01684 g) x (1 meq / 1 mmole) x (100 mg CaCO3 / 2 meq) = 180.278 mg/L as CaCO3, book answer = 180.41

E) (15.00 mg CO3 / L) x (1 mmole CO3 / 60.0089 g) x (2 meq / 1 mmole) x (100 mg CaCO3 / 2 meq) = 24.996 mg/L as CaCO3, book answer = 25.02
Phys.Org News Partner Science news on Phys.org
Security CTO to detail Android Fake ID flaw at Black Hat
Huge waves measured for first time in Arctic Ocean
Mysterious molecules in space
Borek
#2
Sep21-10, 02:59 AM
Admin
Borek's Avatar
P: 23,388
Obviously book uses slightly different molar masses. I wouldn't care too much, differences are below 10-3, that's about as precise as you can determine alkalinity experimentally.
Jim4592
#3
Sep22-10, 10:40 AM
P: 49
alright thank's borek, I thought I would be able to just write it off but that's the farthest off we've ever been, so I figured I'd ask for a second opinion.


Register to reply

Related Discussions
Calculating diamter of wire that will blow if current exceeds 1A Introductory Physics Homework 2
Calculating Speed of Falling Banana - Just Before it Hits Ground? Introductory Physics Homework 2
Calculating Additional Braking Torque Due To Momentum Classical Physics 15
Difference between Identical , Equal , Equivalent Calculus & Beyond Homework 9
Calculating the Capacitance of out of alignment finite parallel plate capacitors Introductory Physics Homework 1