Question

Hi.

I need to confirm if I am correct .

Approximate the following numbers to :
(I) 1 s.f (one significant figure)
(II) 2 s.f ( two significant figure)
(III) 3 s.f (three significant figure).

(a). 0.004816
(b). 50.00168
(c). 0.0009812​

Answer 1

(a)

1 sig: 0.005

2 sig: 0.0048

3 sig: 0.00482

(b)

1 sig: 50

2 sig: 50.

3 sig: 50.0

(c)

1 sig: 0.0010

2 sig: 0.00098

3 sig: 0.000981

Explanation:

Significant Figures Rules:

1. Any non-zero digit is significant.
2. Any trailing zeros after the decimal is significant.
3. Any zeros between 2 significant digits are significant.
4. Zeroes before significant numbers in the decimal place are NOT significant; they are placeholders.

(a)

0.004816 - the zeros are placeholders, so they do not count as sig figs.

(b)

50.00168 - the zeros are between 2 significant figures, so they do count as sig figs.

(c)

0.0009812 - the zeros are placeholders, so they do not count as sig figs