[tarik3001]

Forty (40) rat hairs, each weighing 0.15 mg, were found in a 100.0-kg sample of grain.  Calculate the “concentration” of rat hairs in the grain sample, in mg rat hairs per kg of grain, and in ug rat hairs per g of grain.  If the 40 rat hairs contain a total of 0.00078 mg Zn (determined by flame atomic absorption spectrometry), calculate the Zn concentration in the rat hairs sample in ug Zn per g of rat hair.

What I did...

40 * .15 = 6.0mg hair/ 100kg grain.  so .06mg hair/1kg grain
(.06mg hair/1kg grain) * ( 1000ug/1mg) * (1kg/1000g)  = .06ug hair/1g grain
(,00078mg Zn/.06mg hair) * (1000ug/1mg) * (1000mg/1g) = 1.3 x 10^4ug Zn/1g hair

[Borek]

(,00078mg Zn/.06mg hair)

And not 6 mg  hair?

[tarik3001]

Good catch..thats what I get for speeding through it..does everything else look good? Haven't done these problems since gen chem heh

[Borek]

No other problems spotted, but I just speeded through

[tarik3001]

thanks for your help