Chemistry Teacher & Student

17 mins 49 secs

10 mins 10 secs

42 secs

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43 secs

51 secs

16 mins 16 secs

1 min 21 secs

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31 secs

17 secs

7 mins 30 secs

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6 mins

2 mins 41 secs

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31 secs

9 mins 1 sec

19 secs

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6 mins

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9 mins 20 secs