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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: quangngaicity on July 21, 2015, 11:34:26 PM

Title: Problem about the weight Ca2 ?
Post by: quangngaicity on July 21, 2015, 11:34:26 PM
Hello everyone!

Okay so I'm in a first year chem course at uni and we recently did a 'testing for calcium ion's present' experiment. I'll try and break this down as much as I can because there was a lot of info in the prac, so here goes:
1. 20mL of milk (with 175mg/100mL Ca2+ ions present) was added to 15mL of deionized water, then 8mL of 1M Acetic acid was added, which caused a precipitate.
2. The precipitate was separated using vacuum filtration and then 40mL of 0.3M Ammonium Oxalate ((NH4)2C2O4) was added to the filtrate.
3. Calcium Oxalate was formed (CaC2O4) and its mass was recorded (0.3056g)

I need to calculate the mass of calcium ions in the CaC2O4 precipitate... and need as much help as i can get!

Any help/advice is much appreciated!
Title: Re: Problem about the weight Ca2 ?
Post by: Dan on July 22, 2015, 01:38:42 AM
1. How many moles of Ca2SO4 Ca2C2O4?
2. How many moles of Ca?
3. How many grams of Ca?


Edit: Ca2SO4 typo corrected
Title: Re: Problem about the weight Ca2 ?
Post by: PhotoElectroMaterials on July 23, 2015, 10:41:07 AM
Dan question 1 should be 1. how many moles of CaC2O4?

Quang*   answering these 3 questions of Dan will give you the answer you want.
Title: Re: Problem about the weight Ca2 ?
Post by: Dan on July 23, 2015, 11:28:17 AM
Quote from: PhotoElectroMaterials on July 23, 2015, 10:41:07 AM
Dan question 1 should be 1. how many moles of CaC2O4?

Thanks for the correction.