Boxed or circled, and submit The half-life of phosphorus is 14 days. A 90 gram sample was produced.
How much of it would be left after 24 days?

Answer is in the photo. I couldn't attach it here, but uploaded it to a file hosting. link below! Good Luck!

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1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles