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Topic: Chemistry  (Read 3167 times)

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Offline Babygal

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Chemistry
« on: January 16, 2011, 02:48:28 PM »
Hey may someone please check my answer to question number 2.

Offline rabolisk

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Re: Chemistry
« Reply #1 on: January 16, 2011, 03:23:58 PM »
You're doing something wrong on number 2. The data is 100% linear, and if you plotted the equation you had, along with the data points given, you will see that this is not the correct equation. You need to find the equation that satisfies all 5 data points (I can tell that it will by inspection).

Offline Babygal

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Re: Chemistry
« Reply #2 on: January 16, 2011, 04:47:17 PM »
Thanks. I just did the question again and this is what I am getting: y = 583.33x - 3E-16. Still it is wrong.

Offline rabolisk

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Re: Chemistry
« Reply #3 on: January 16, 2011, 04:54:10 PM »
3E-16 is incredibly close to 0.

Offline ironnica

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Re: Chemistry
« Reply #4 on: January 18, 2011, 05:58:36 AM »
Through excel i got the intercept to be 2E-19, correlation of 1

formula = y = 0.0017x +2E-19

Edit: I dont mean to infringe the rules by giving the answer. I am encouraging the comparrison between excel (07) and the software used in the question

Offline DevaDevil

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Re: Chemistry
« Reply #5 on: January 18, 2011, 12:11:27 PM »
the cutoff point is irrelevant as it is not asked in the question (and I agree with rabolisk, even if you didn't check by hand to see the graph actually goes through the origin, the computer-given values are so small that they are negligible)

Now for the slope; I did not plot it in a computer program, but can see the line is 100% accurately linear. If you do plot it though, be careful of plotting the x and y values correct (do not mix them up, a common mistake). Then when the computer gives you a value, take the extra minute of time to check if this is a reliable value by checking it by hand. Remember: slope of a graph = dy/dx

then finally check significant numbers

Offline ironnica

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Re: Chemistry
« Reply #6 on: January 18, 2011, 01:01:42 PM »
Wow, am I a plank.

Yeah, scrap my answer. Somehow i never make that mistake in lab.

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