Question

Anyone on? I have a few questions on significant figures and I was wondering if you could check my answers?

Answer 1

@ganeshie8

Answer 2

@Nnesha

Answer 3

Rules:

1. All non-zero digits are significant.

For example:
123. (3 sig figs)

2. Zeros between non-zero digits are significant.

For example:
12.507 (5 sig figs)

3. Zeros to the left of the first non-zero digit are not significant.

For example:
1.02 (3 sig figs)
0.12 (2 sig figs)
0.012 (2 sig figs)

4. If a number ends in zeros to the right of the decimal point, those zeros are significant.

For example:
2.0 (2 sig figs)
2.00 (3 sig figs) {This signifies greater accuracy.}

5. If a number ends in zeros to the left of the decimal point, those zeros may or may not be significant.

For example:
If we make a statement that the weight of an object is 120 g, how do we convey our knowledge of whether the balance was accurate to ± 1 g or ± 10 g?

Answer: The ambiguity can be removed by using exponential notation.
The weight can be expressed as 12. x 101 g or 1.2 x 102 g if we wish to quote unambiguously to 2 sig figs, and 12.0 x 101 g or 1.20 x 102 g if we have a confidence level extending to 3 sig figs.
Note: We cannot write 120.0 g since this requires known accuracy of ± 0.1 g.

Answer 4

Wow this is an amazing description, thank you so much!

Answer 5

yes Tara is awesome....@twistnflip

Answer 6

I usually help people, but I just started AP chemistry and I completely blanked on sig figs. My teacher assigned homework without doing notes or reviewing (which is ok except for the fact that I don't have my textbook yet lol)

Answer 7

Calculations with numbers having different accuracies

Multiplication or Division: the result can have no more sig figs than the least accurate number. For example:

If an object has mass of 29.1143 g and a volume of 25.0 cm3, then its density is given by

Density = 29.1143 g / 25.0cm-3 = 1.164572 g cm-3 = 1.16 g cm-3

Addition or Subtraction: the result must be reported to the same number of decimal places as the number with the fewest decimal places. For example:

19.2g+ 0.4745g+127. g=146.6745g= 147. g because one weight is known only to the nearest 1g

NOTE: Round off numbers only at the END of calculations; otherwise, errors may be inadvertently carried through.

Answer 8

ok, got it! Thanks again! you the bomb

Answer 9

No problem!! It was good for me to review them a little too since school is starting back up soon so it helped me too!!