[jmaillou]

Hey,I am having trouble with these stoichiometry questions, and I have a quiz on this stuff tomorrow.  If you could please help, that would be great.

1.  A compound is analyzed for its bromine content by converting all bromine to AgBr. If a sample of the compound of mass 0.295g gave 0.668g of AgBr on analysis, what was the mass percent of bromine present.

2. The body's only use for the element fluorine is in tooth enamel, which consists of fluorapatite,Ca₅(PO₄)₃F. Use of a fluoridated toothpaste converts hydroxyapatite Ca₅(PO₄)₃(OH) into fluoropatite.  If you convert 0.50g of hydtoxyapatite into fluorapatite, what mass of flourine have you incorporated into your teeth.

[jmaillou]

sorry. looks like the last part of question 2 got cut off :S .  It says "If you convert 0.50g of hydroxyapatite into fluoropatite, what mass of fluorine have you incorporated into your teeth?

[Padfoot]

Start by converting mass to moles.

[Borek]

Start by converting mass to moles.

Won't hurt, but you better start with writing reaction equations

[Borek]

sorry. looks like the last part of question 2 got cut off :S .  It says "If you convert 0.50g of hydroxyapatite into fluoropatite, what mass of fluorine have you incorporated into your teeth?

I have edited your post - there was a typo and one tag was not closed. It is OK now.