## Significant Figures

emma brinton_3B
Posts: 53
Joined: Fri Aug 09, 2019 12:17 am

### Significant Figures

Hi! i haven't taken chemistry since sophomore year of high school and i was wondering if anyone could explain sig figs to me?

Rebekah Alfred 1J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am
Been upvoted: 1 time

### Re: Significant Figures

Hi! Here are some of the basic rules for significant figures:
1. All non-zero numbers are significant.
Ex. 457 has 3 significant figures.

2. Zeros in between two non-zero numbers are significant.
Ex. 9023 has 4 significant figures.

3. Trailing zeros (the zeros at the end) are only significant if the number has a decimal point after (i.e. 120.) or when the trailing zeros are in the decimal portion of the number.
Ex. 5.460 has 4 significant figures.
15600. has 5 significant figures.
5000 has 1 significant figure.

4. Zeros to left of the first nonzero digit are insignificant.
Ex. 0.000007 has 1 significant figure.
0.0025 has 2 significant figures.

Rebekah Alfred 1J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am
Been upvoted: 1 time

### Re: Significant Figures

If you want to practice determining how many significant figures a number has, this could be helpful:

Rebecca Remple 1C
Posts: 137
Joined: Wed Sep 18, 2019 12:16 am
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### Re: Significant Figures

I agree with everything Rebekah said! To add onto it, sig figs are important when calculating your final answer. For example, if you were multiplying two numbers - 2.0 (2 sig figs) and 554.0 (4 sig figs) - your answer would have as many sig figs as the value with the lowest number of sig figs. The value with the lowest number of sig figs would be 2.0, which has 2 sig figs (one non-zero number and one zero after the decimal point). In this case, 2.0 * 554.0 = 1108, but since 1108 has 4 sig figs you would have to round it. This would give you 1100, which has two sig figs (remember, trailing zeroes don't count). I hope this helps!

serenabirkhoff_1K
Posts: 63
Joined: Sat Aug 17, 2019 12:15 am

### Re: Significant Figures

Rebecca Remple 1J wrote:I agree with everything Rebekah said! To add onto it, sig figs are important when calculating your final answer. For example, if you were multiplying two numbers - 2.0 (2 sig figs) and 554.0 (4 sig figs) - your answer would have as many sig figs as the value with the lowest number of sig figs. The value with the lowest number of sig figs would be 2.0, which has 2 sig figs (one non-zero number and one zero after the decimal point). In this case, 2.0 * 554.0 = 1108, but since 1108 has 4 sig figs you would have to round it. This would give you 1100, which has two sig figs (remember, trailing zeroes don't count). I hope this helps!

This helped so much thank you!!

serenabirkhoff_1K
Posts: 63
Joined: Sat Aug 17, 2019 12:15 am

### Re: Significant Figures

Rebecca Remple 1J wrote:I agree with everything Rebekah said! To add onto it, sig figs are important when calculating your final answer. For example, if you were multiplying two numbers - 2.0 (2 sig figs) and 554.0 (4 sig figs) - your answer would have as many sig figs as the value with the lowest number of sig figs. The value with the lowest number of sig figs would be 2.0, which has 2 sig figs (one non-zero number and one zero after the decimal point). In this case, 2.0 * 554.0 = 1108, but since 1108 has 4 sig figs you would have to round it. This would give you 1100, which has two sig figs (remember, trailing zeroes don't count). I hope this helps!

emma brinton_3B
Posts: 53
Joined: Fri Aug 09, 2019 12:17 am

### Re: Significant Figures

serenabirkhoff_1K wrote:
Rebecca Remple 1J wrote:I agree with everything Rebekah said! To add onto it, sig figs are important when calculating your final answer. For example, if you were multiplying two numbers - 2.0 (2 sig figs) and 554.0 (4 sig figs) - your answer would have as many sig figs as the value with the lowest number of sig figs. The value with the lowest number of sig figs would be 2.0, which has 2 sig figs (one non-zero number and one zero after the decimal point). In this case, 2.0 * 554.0 = 1108, but since 1108 has 4 sig figs you would have to round it. This would give you 1100, which has two sig figs (remember, trailing zeroes don't count). I hope this helps!
thank you so much for the elaboration it really helped!