DP Chemistry (last assessment 2024)

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Question 17N.3.sl.TZ0.1b.i

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Date November 2017 Marks available [Maximum mark: 1] Reference code 17N.3.sl.TZ0.1b.i
Level sl Paper 3 Time zone TZ0
Command term Suggest Question number b.i Adapted from N/A
b.i.
[Maximum mark: 1]
17N.3.sl.TZ0.1b.i

A student set up a simple voltaic cell consisting of a copper electrode and a zinc electrode dipped in sodium chloride solution.

The student gradually increased the distance, d, between the electrodes to study the effect on the initial current, I, passing through the light bulb.

The student hypothesized that the initial current would be inversely proportional to the distance between the electrodes.

The following data was collected over five trials.

The data did not support the student’s hypothesis. He investigated other possible relationships by plotting a graph of the average current against the distance between the electrodes. He obtained the following best-fit line with a correlation coefficient (r) of −0.9999.

(b.i)

Suggest what the correlation coefficient of −0.9999 indicates.

[1]

Markscheme

negative correlation

OR

model/prediction matches results

OR

99% of variance accounted for

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