STATISTICS: Assume that the following data was collected for a chemical reaction where reactants A and B are reacting to form products C and D. As the products are formed, you measure their masses at two minute increments.

Time (min) Amount of product(g)
2 3
6 5
7 7
8 10
10 13
12 17
14 21
16 26
18 34
20 50

Question

STATISTICS: Assume that the following data was collected for a chemical reaction where reactants A and B are reacting to form products C and D. As the products are formed, you measure their masses at two minute increments.

Time (min)	Amount of product(g)
2	3
6	5
7	7
8	10
10	13
12	17
14	21
16	26
18	34
20	50

anonymous · Answer

a) What is the equation for the model of best fit?
Would it be log y=-0.076x*log x-o.1148? Or yhat=8.846-2.42x? Those are what I got.
b) What does your model predict would have been the amount present at 5 minutes?
I have no idea how to do this one..
c) At what time would 25.1 grams remain, according to your model?
15?
d) Are the products formed at a constant rate over time? Explain.
How would I determine this?

anonymous · Answer

Have you made a scatter plot yet?

anonymous · Answer

I can tell you this much for (a) a line with a negative slope is not going to fit the data at all.

anonymous · Answer

Yes, I have.

anonymous · Answer

I'm sure you can tell from the shape of it that it's an exponential relation.
Fit an exponential model to it and then sub in x=5 to answer part (b). Put that point on your scatter plot to see that it fits in with the rest.

anonymous · Answer

How do I input that on my calculator (Ti-84)? Sorry, I feel so stupid >.>

anonymous · Answer

Your guess of 15min. for part (c) makes sense. After you have your equation, you can probably tighten up the precision of that.

anonymous · Answer

Eh, this stuff takes practice; don't sweat it.
On the TI-84 input your data to L1 and L2 (STAT-EDIT)
Then go to STAT-CALC and choose ExpReg L1,L2,Y1

anonymous · Answer

(you can choose Y1 by going to VARS-YVARS-Function-y1)

anonymous · Answer

I'm trying..

anonymous · Answer

I don't think I got it right.. It says 2.428*1.164
r2=.980
r=.990

anonymous · Answer

That's what I got too. You're just missing the exponent, x on the 1.164.

anonymous · Answer

$$y=2.4285(1.1646)^x$$

anonymous · Answer

for x=5, I got 5.2026

anonymous · Answer

I got 5.2036, but there might be round-off error somewhere.

anonymous · Answer

so that would be the answer to b?

anonymous · Answer

Yes, but make sure you include the unit of grams depending on how you are to submit your answers.

anonymous · Answer

thank you for explaining that to me :)