# Chemistry

How does Significant Figures work?

If i had a number: 1,007,000 is that with 4 sig figs or 7 sig figs?

I checked 5 different resources and gotten conflicting answers.

Help!

The answer will depend on what's being measured and how it's being measured.
If that number were the amount of shares of common stock of some public company that were traded today then it could be 7 significant figures. On the other hand, if it were the number of miles some object might be from the earth then there might be only 4 significant figures. If it's some kind of measurement then most likely it has only 4 sig. figures. If it's something that can be counted, and the process is extremely accurate and verifiable, then there could be more than four signif. figures.
So the short answer is...it depends.

It is hard to tell. If there was a period at the end, such as 1,007,000. then the answer is 7 sig figures. But with no period, we don't know if the zeros are sig or not. GENERALLY, I think the rule is not to count them if there is no period. In such practice, the number would be written as 1.007E+6. Then there would be no confusion and we would count 1, 0, 0, and 7 as sig figures.

The reason you get conflicting answers is this:
The notation for significant zeros is changing. The IBM keyboard is largely to blame. Years ago, trailing significant zeros could be labeled with an overscore (a line above the number) to indicate it was significant. We cant make overscores on the IBM keyboard. So panic has ensued.
Years ago, if your number had a significant zeros, the least significant zero had an overscore (I can type it with an underscore 1,007,000, (now the number has six significant digits), but no overscore. For awhile, bold was used to indicated the least significant zero (1,007,000, but that faded quickly. So now there is no method except shifting to scientific notation (decimals to the right of numbers and decimals are significant, ie 1.00700 is seven sig digits), or being told initially.
This above applies to measurements: as Roger pointed out, counting numbers, or defined numbers,(100years in a century) are infinitely precise. If 1007000 had been counted, it does not have seven significant digits, it has infinite significant digits..It cannot determine the precision of your final outcome. This confusion based on the disruption of typesetting by the IBM keyboard in computers in the last 20 years is probably the reason you got five different answers. The most common rules widely adhered to are here:

There are only three rules cited there.

I remember just 17 years ago, texts listed as many as seven rules.

Thanks for this refresher Bob. It's been awhile since I looked at signif. figs. I wasn't aware that the short-comings of the keyboard were partly to blame for the confusion here. I do remember using the bar, but I couldn't remember what the rules were for it. I think some sets of rules also tell how to make calculations with measurements and determine sig. figs., that might account for the different rule counts.
In any case -if you read this Summer- always look at what your text states and know what the instructor expects. You should be alright if you do that.

1. 👍 0
2. 👎 0
3. 👁 325

## Similar Questions

1. ### math/chem significant figures

Which of the answers for the following conversions contains the correct number of significant figures? A)2.543 m x 39.4in/1m=100.1924in B)2 L x 1.06qt/1L=2.12 qt C)24.95 min x 1hr/60 min=0.4158 hr D)12.0 ft x 12in/1ft x

2. ### chemistry

Liquid hydrogen peroxide, an oxidizing agent in many rocket fuel mixtures, releases oxygen gas on decomposition. 2 H2O2(l) 2 H2O(l) + O2(g) Hrxn = -196.1 kJ How much heat is released when 529 kg H2O2 decomposes? ( ......... ) KJ

3. ### physics online

Assuming that Albertine's mass is 60.0 , what is , the coefficient of kinetic friction between the chair and the waxed floor? Use = 9.80 for the magnitude of the acceleration due to gravity. Assume that the value of found in Part

4. ### physics

2. A car accelerates uniformly from +10.0 m/s to +40.0 m/s over a distance of 125 m. How long did it take to go that distance? Show all your work, including the equation used, given and unknown quantities, and any algebra

1. ### SIG FIGS

How many significant figures does 22.0, 0.22, 22. , 0.022? Im just confused as to the decimal addition to numbers and what the sig figs will be for them. If you don't mind can you please state some rules for sig figs that are

2. ### Math

Rounding to significant figures 99.98 to 3 significant figures Can it apply to this number as if I round to 100 this is one significant figure or we keep it as 99.9. Please clarify And same number to 2 sig figure Will it be 100?

3. ### Chemistry

7.0 ml of 6.0 M NaOH are diluted with water to a volume of 400 ml. You are asked to find the molarity of the resulting solution. The total number of moles of NaOH is not changed on dilution. Calulate the molarity. Work:

4. ### chemistry

Suppose you are asked to find the area of a rectangle that is 2.1-cm \rm cm wide by 5.6-cm \rm cm long. Your calculator answer would be 11.76 cm 2 \rm cm^2 . Now suppose you are asked to enter the answer to two significant

1) Round 578.683 m, 47.3333 kg, and 789.5 cm to four significant figures. 2) Find the weight of a 12.25 kg dog. Round your answer to the correct number of significant figures. Use weight=massxfree-fall acceleration. 3) Round

2. ### physics

Find the direction and magnitude of the following vectors. A⃗ =( 22 m )x^+( -15 m )y^ Express your answer in degrees using three significant figures. θA = Part B Express your answer in meters using two significant figures.

3. ### physics

You pick up a 3.2 kg can of paint from the ground and lift it to a height of 1.4 m . Part A How much work do you do on the can of paint? Express your answer to two significant figures and include the appropriate units. Part B You

4. ### Math in Science

A student measures the volume of a liquid and finds it to be 40mL. How many significant figures are in the measurement? 1 *** 2 3 4 Calculate the area, with the appropriate number of significant figures, of a rectangular room that