anonymous one year ago acetic acid 0.921% (w/w) 100grams. The acetic acid will be measured by weight. how much is used?

1. anonymous

What does (w/w) mean?

2. anonymous

weight in weight

3. anonymous

4. anonymous

@aaronq come in here. So im guessing it means : $\sf \frac{0.921 ~g~C_2H_3O_2}{100~g~comp}$

5. anonymous

i sent the actual question above. with 4 answers..

6. aaronq

acetic acid 0.921% (w/w) 100 grams. means that there is 0.00921*100 g =0.921 g of acetic acid and 100 g - 0.921 g = 99.079 g of solvent

7. anonymous

oh i see how it works now

8. aaronq

from that picture posted, it's A and C, because of the units

9. aaronq

okay, coooool

10. anonymous

so its a and c? why?

11. aaronq

because of the units, 0.921 g = 921 mg

12. anonymous

ok. thank you so much.. both of you ..

13. anonymous

Are you willing to help me understand other questions?

14. aaronq

no problem guyses, idk if you're asking me, but if so, you should post in the chem section

15. anonymous

im asking either of of you

16. anonymous

if not, would you really consider this chem?

17. aaronq

yeah

18. anonymous

its actually pharmacy compounding math

19. aaronq

pharmacy is based from chem and bio

20. anonymous

are you willing to help me understand a few other questions ?

21. aaronq

yep

22. anonymous

ok thank you i will post the next question

23. aaronq

kk

24. anonymous

25. anonymous

26. anonymous

I am trying to get some of these done before work tomorrow

27. anonymous

along with understanding them

28. aaronq

so, v/v means volume by volume, it's pretty straight forward that in 100 mL of 50 % v/v glycerin solution there is 50 mL of glycerin.

29. anonymous

30. anonymous

i should have just read that one. that was common sense but im old..

31. anonymous

is the answer to 17. 6.25ml?

32. aaronq

sorry, i had to step away from the keyboard. yes, that's the answer. you basically just have to watch the units

33. anonymous

its ok . i am trying to do this, which most has nothing to do with what i do at work. and thank you so so much

34. anonymous

35. anonymous

here is another one if you can help thank you

36. aaronq

which one?

37. anonymous

i need to do all 3 questions? so what ever you can help with

38. anonymous

well one is d

39. anonymous

so 2 and 3

40. aaronq

b) is 400 mg 0.02*20 g =0.4 g = 400 mg

41. anonymous

wow thank you.. at least i can see it now

42. aaronq

for c) you add the whole masses and make a dilution $$2\%*20g=x\%*(20~g+30~g+30~g)\rightarrow x\%=0.5\%$$

43. aaronq

lol sorry that sounds to weird, i meant "add all the masses" not "the whole.." lol

44. anonymous

45. aaronq

yep

46. aaronq

grams is a unit of mass

47. anonymous

you are a great help.. can you help with a few more? i dont want to over welcome my help

48. aaronq

I would but i have to go do laundry and stuff. Hopefully someone else can come help ya, if you can't find help here, try the chem section.

49. anonymous

50. anonymous

ok thank you so much