Question

Suppose your lab partner recorded a measurement as 100 g.

a. Why is it difficult to tell the number of significant figures in this measurement?
b. How can the number of significant figures in such a number be made clear?

a) a. The measurement lacks precision; b. Add a decimal point after 100.
b) a. The measurement is in scientific notation; b. Use standard notation.
c) a. The measurement is exact; b. Round to the nearest whole number.
d) a. The zeros are trailing; b. Add a decimal point after 100.0.

Answer 1

It's difficult to tell the number of significant figures in 100 g because trailing zeros can either be significant or placeholders. The issue is resolved by adding a decimal point (100.0) or using scientific notation (1.00 × 10²), both indicating that the zeros are significant.

Step-by-step explanation:

The difficulty in determining the number of significant figures in the measurement 100 g is because it is not clear whether the zeros are significant or if they are just placeholders. This ambiguity arises when trailing zeros appear to the left of an implied decimal point, as with 100. To resolve this, scientific notation or a clear decimal indicator can be used. For example, expressing 100 g as 1.00 × 102 would indicate three significant figures, while 100. indicates the zeros are intended to be significant.

Therefore, the correct answer to the question is: (d) a. The zeros are trailing; b. Add a decimal point after 100.0. By doing so, it explicitly shows that the zeros are significant because any zeros following a non-zero number and a decimal point are counted as significant.