[axl617]

1. Fluorine compounds are added to water, the concentration being 0.90 ppm.

a. What amount of fluoride present 1.0g of water?

workout out- (just need to know what the number mean)

Divided 0.90 pm by 1,000,000, which I assume is the grams of substance per kilogram?

Then divided that number by fluorines molar mass (19) to get the answer of 4.7x10^-8

b. How much fluoride ions would you swallow if you drank 200ml water?

2. Convert 0.00036M (molarity) of Ca(OH)2 to ppm

working- I found the molar mass of the compound being ~74

3. For 0.20M of K2SO4, calculate mol of K+ ions, Sulfate ions and oxygen atoms

working - Molar mass I found to be ~174

[axl617]

4. Find concentration of vitamin c in g L^-1 when 40mg/100ml and do same for carbonhydrate at 8.5g/100ml

I'm guessing I just divided 40mg/100ml and 8.5g/0.1L but not sure if this makes sense?

[AWK]

40mg/100ml

express in grams and liters before dividing

[axl617]

40mg/100ml

express in grams and liters before dividing

Thanks. Would it be possible to get help with the other questions?

[AWK]

8.5g/0.1L

OK, just divide these numbers

[skbuncks]

1. Fluorine compounds are added to water, the concentration being 0.90 ppm.

a. What amount of fluoride present 1.0g of water?

workout out- (just need to know what the number mean)

Divided 0.90 pm by 1,000,000, which I assume is the grams of substance per kilogram?

Then divided that number by fluorines molar mass (19) to get the answer of 4.7x10^-8

b. How much fluoride ions would you swallow if you drank 200ml water?

2. Convert 0.00036M (molarity) of Ca(OH)2 to ppm

working- I found the molar mass of the compound being ~74

3. For 0.20M of K2SO4, calculate mol of K+ ions, Sulfate ions and oxygen atoms

working - Molar mass I found to be ~174

ppm is parts per million

ie. mg/Kg because there are 1000000 mg in a Kg
Other units would be mg/L when talking about aqueous systems.
So for question 1b.
90ppm is 90mg/Kg. First convert to g/Kg then g/g. To then convert to mol/g divide by the mol.wt.

For part b) convert from molarity to g/L then to mg/L = ppm

skb