Question

How many significant figures are in each of the following? (a) 0.000050 (b) 7000 (c) 8.004 (d) 457,000 (f) 900. (g) 3.8 moles of silver.

Answer 1

To determine the number of significant figures in each of the provided numbers, we follow these rules:

1. All non-zero digits are significant.
2. Any zeros between non-zero digits are significant.
3. Leading zeros (zeros to the left of the first non-zero digit) are not significant.
4. Trailing zeros in a number without a decimal point are not significant, while trailing zeros in a number with a decimal point are significant.

Now, let's analyze each of the given numbers:

(a) **0.000050**: The leading zeros are not significant. The significant digits are "5" and the trailing zero. Therefore, it has **3 significant figures**.

(b) **7000**: Since there is no decimal point, the trailing zeros are not considered significant. Therefore, it has **1 significant figure**.

(c) **8.004**: All the digits are non-zero or zero between non-zero digits, which are significant. Therefore, it has **4 significant figures**.

(d) **457,000**: Without a decimal point, the trailing zeros are not significant. Thus, it has **3 significant figures**.

(e) **900**: Similar to example (b), since there is no decimal point, only the "9" is significant. Therefore, it has **1 significant figure**.

(g) **3.8 moles of silver**: Both digits are significant, so it has **2 significant figures**.

In summary:
- (a) 3 significant figures
- (b) 1 significant figure
- (c) 4 significant figures
- (d) 3 significant figures
- (e) 1 significant figure
- (g) 2 significant figures