Physical and Chemical Changes Essay examples

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Physical and Chemical Changes
Say you are presented with two beakers, beaker A and beaker B, each containing a white, powdery compound. * a. From your initial observations, you suspect that the two beakers contain the same compound. Describe, in general terms, some experiments in a laboratory that you could do to help prove or disprove that the beakers contain the same compound. You may try some of the followings: * Dissolving in water * Dissolving in different chemical solution * Heating both substance to see if they come out with different results * Doing the flame test for both solution to see if they can come out with different results * etc * b. Would it be easier to prove that the …show more content…
The least number of significant figures is 2; hence, the answer must have 2 significant figures, and in fact it does.

* e. Another student performs the calculation (5 × 5.163 g) + 2.09 and reports an answer of 32.1g. Is this the correct answer? If not, what might this student have done incorrectly? Not correct. 5 has only 1 significant figure. Hence, 5 X 5.163 g has only 1 significant figure, which is equal to 30 g. Therefore, the reported final answer can not have 3 significant figure. * f. Yet another student performs the calculation (5.00 × 5.163 g) + 2.09 and reports an answer of 30 g. Is this the correct answer? If not, what did this student probably do incorrectly? Not correct answer. 5.00 has 3 significant figures 5.163 has 4, and 2.09 has 3 significant figures But the answer 30 g only has 1 significant figures ( note that there is no decimal place, so the number 0 in 30 g does not count as a significant figure) * g. Referring to the calculations above, outline a procedure or rule(s) that will always enable you to report answers using the correct number of significant figures.
If the addition is involved in the calculation only, choose the least decimal place for the answer.

If the multiplication is involved only, choose the least significant figures for the
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