How about a half mol of instant coffee powder in your cup?
The formula for caffeine is C8H10N4O2 ... see if you can remember the molecular weights (rounded off to the nearest gram) for each of these elements, rather than looking them up.
| 1 H 1.01 |
2 He 4.00 |
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| 3 Li 6.94 |
4 Be 9.01 |
5 B 10.81 |
6 C 12.01 |
7 N 14.01 |
8 O 16.00 |
9 F 19.00 |
10 Ne 20.18 |
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| 11 Na 22.99 |
12 Mg 24.30 |
13 Al 26.98 |
14 Si 28.09 |
15 P 30.97 |
16 S 32.07 |
17 Cl 35.47 |
18 Ar 39.98 |
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| 19 K 39.10 |
20 Ca 40.09 |
21 Sc 44.96 |
22 Ti 47.88 |
23 V 50.94 |
24 Cr 51.94 |
25 Mn 54.94 |
26 Fe 55.85 |
27 Co 58.93 |
28 Ni 58.69 |
29 Cu 63.55 |
30 Zn 65.39 |
31 Ga 69.72 |
32 Ge 72.61 |
33 As 74.92 |
34 Se 78.96 |
35 Br 79.90 |
36 Kr 83.80 |
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BUT, the question was, how many grams in half of a mol, so multiply your answer by 0.5...
So 97 grams would be one heck of a cuppa joe.
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