Q50 E
Question
The following quantities were reported on the labels of commercial products. Determine the number of significant figures in each.
(a) 0.0055 g active ingredients
(b) 12 tablets
(c) 3% hydrogen peroxide
(d) 5.5 ounces
(e) 473 mL
(f) 1.75% bismuth
(g) 0.001% phosphoric acid
(h) 99.80% inert ingredients
Step-by-Step Solution
Verified- 2
- infinite
- 1
- 2
- 3
- 3
- 1
- 4
We determine the number of significant figures with the help of the following rules:
- All non-zero digits are significant.
- Zeros present in between non-zero digits are significant.
- Zeros which come after the decimal point are significant (trailing zeros).
- Zeros which come before the decimal and any non-zero number are insignificant (leading zeros) since they are only used to depict the place of the decimal.
- Exact numbers have an infinite number of significant digits.
a) 0.0055 g active ingredients: The three zeroes are leading and hence insignificant, thus total number of significant figures = 2
b) 12 tablets: The number of significant figures in exact numbers is always infinite.
c) 3% hydrogen peroxide: The number of significant figures is 1.
d) 5.5 ounces: The number of significant figures is 2, since both digits are non-zero.
e) 473 mL: The number of significant figures is 3.
f) 1.75% bismuth: The number of significant figures is 3, they are non-zero digits.
g) 0.001% phosphoric acid: The number of significant figures is 1, since the zeroes are leading zeros.
h) 99.80% inert ingredients: The number of significant figures is 3, since we have a trailing zero which is significant.