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Chemistry Past Questions and Answers

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Chemistry Questions

Question 436:

Which of the following conduct electricity?

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A Sulfur
B Graphite
C Diamond
D Red phosphorus
E Yellow phosphorus

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Question 437:

An organic compound contains 72% carbon, 12% hydrogen and 16% oxygen by mass. The empirical formula of the compound is

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A C<sub style='font-size: smaller;'>8</sub>H<sub style='font-size: smaller;'>22</sub>O<sub style='font-size: smaller;'>3</sub>
B C<sub style='font-size: smaller;'>6</sub>H<sub style='font-size: smaller;'>10</sub>O<sub style='font-size: smaller;'>3</sub>
C C<sub style='font-size: smaller;'>12</sub>H<sub style='font-size: smaller;'>12</sub>O
D C<sub style='font-size: smaller;'>6</sub>H<sub style='font-size: smaller;'>12</sub>O
E C<sub style='font-size: smaller;'>3</sub>H<sub style='font-size: smaller;'>6</sub>O

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Question 438:

0.499g 0f CuSO<sub style='font-size: smaller;'>4</sub>.xH<sub style='font-size: smaller;'>2</sub>O when heated to constant weight gave a residue of 0.346g. the value of x is? (Cu = 63.5, S = 32.0, O = 16, H = 1)

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A 0.5
B 2.0
C 3.0
D 4.0
E 5.0

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Question 439:

In the experiment, which of the following observations would suggest that a solid sample is a mixture? The

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A Solid can be ground to a fine powder
B Density of the solid is 2.25gdm<sup style='font-size: smaller;'>-3</sup>
C Solid begins to melt at 573k but is not completely melted until 648k
D Solid absorbs moisture from the atmosphere and turns into liquid
E Solid melts at 300k

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Question 440:

Hydrogen diffuses through a porous plug

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A At the same rate as oxygen
B At a slower rate than oxygen
C Twice as fast as oxygen
D Three times as fast as oxygen
E Four times as fast as oxygen

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