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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: citrus137 on January 15, 2017, 01:03:46 PM

Title: Solubility and Solutions calculations questions?
Post by: citrus137 on January 15, 2017, 01:03:46 PM

Hi, so the question reads: "1. A Sodium fluoride toothpaste contains 1450 ppm of fluoride ions. Knowing that the molecular weight of NaF is 41.99 g/mol and the atomic mass of F- is 18.99 g/mol, calculate how much NaF is need to prepare 30g of the toothpaste?"

Any help on how to approach such a question as I am seriously stumped on how to even begin to approach this?

Thanks for the *delete me*

Title: Re: Solubility and Solutions calculations questions?
Post by: AWK on January 15, 2017, 01:08:23 PM

Do you know a definition of ppm concentration?

Title: Re: Solubility and Solutions calculations questions?
Post by: citrus137 on January 16, 2017, 04:30:59 AM

Quote from: AWK on January 15, 2017, 01:08:23 PM

Do you know a definition of ppm concentration?

Different places report ppm to be different things, but I'm assuming in this question it is referring to 1450 g per 1,000,000g?

Title: Re: Solubility and Solutions calculations questions?
Post by: AWK on January 16, 2017, 05:12:24 AM

Then calculate mass of 1450 g F^- to grams of KF and scale down to 30 g.