Significant Figures With Rules in Chemistry

Significant Figures

What are Significant Figures?

The reliable digits in a number that are known with the certainty are called significant figures. The last digit of measured number is generally considered uncertain by ± 1.

For Example : 
0.0112g contains three S.F and uncertainty is ± 0.0001 mg.
11/2mg contains three S.F and uncetainty is ± 0.1mg.

The uncertainty and the number of S.F do not change when measurement is expressed in sub units.

For Example:
0.0112g = 11.2mg in 0.0112g uncertainty is ± 0.0001g and in 11.2 mg uncertainty is ± 0.1mg as 0.0001g = 0.1mg. Therefore uncertainty and number of S.F do not change.

Number Of Significant Figures (Digits) Depends Upon :

  1. The accurancy of the measuring instrument.
  2. The size of the object to be measured.
In any series of measurements, the measured numbers are obtained to a certain degree of precision. The precision of measured is indicated by the number of significant figures.
  • Precision : How close a series of measurements are to each other.
  • Precise : Consistent (Reliability)
  • Accuracy : How close a measurement is to the accepted value.
  • Accurate : Correct.

Rules For Determining Significant Figures

  1. All non zero digits are considered significant : For example 123.45 have five significant figures = 1,2,3,4 and 5.
  2. Zero between two non zero digits are significant B/C these are obtained through actual measurement : For example 101.12 have five significant figures 1,0,1,1 and 2.
  3. Zeros locating the decimal point in a number less than one are not significant figures : For example 0.00012 has two significant figures 1 and 2.
  4. Final Zero to the right of the decimal point are significant figures b/c they ruke out the possiblity of any other digit : For example 12.2300 have six significant figures 1,2,2,3,0 and 0.
  5. Zeros that locate the decimal point in a number larger than one are not necessarily significant : For example 40cm have one S.F 4.
A number with all zero digits (e.g 0.000) has no significant digits, because the uncertainty is larger than the actual measurement.

Comments

Post a Comment

Popular posts from this blog

Blessing Of Science Essay

Image
Science has made great progress today. Now inventions have changed our lives completely. Man is leading a comfortable and luxurious life as a result of blessings of science. The greatest achievement of science is the fastest means of communication. People are in touch with each other around the globe with the help of phones, e-mails, faxes and satellite phones. The distances have reduced and people reach from one corner of the world to the other in supersonic jets. Harmful diseases have been eradicated with the advancement in health science. The life expectancy is increasing day by day. Food production has increased with the research in agricultural science. The ever increasing population of the world can go on eating without the fear of hunger or famine. New entertainments are available to people who can watch a large number of TV channels on cable. Mass production in modern industries is responsible for meeting needs of people. Science is providing a solution  to every...
Read more

My Favourite Game Cricket Essay

Image
Cricket was the national game of England. It has now become the second national game of Pakistan too, The top six cricket teams of the world at present are Australia, India, Srilanka, New Zealand, England South Africa, Pakistan and West Indeas. The first cricket club in England was hambled which existed till 1825. This game is placed upon a large piere of levelled ground. Generally, It is played on turf. Batting is done on the pitch. On this pitch stumps are fixed 22 yards aparts. There are 3 stumps on each side. On the top of these stumps are placed two balls. There are two umpires, one at each set of stumps. There cricket match is played between two teams of eleven players each. Before the play, captains of both teams go to the umpires for toss. The winner of the toss has choice to bat or field first, Six players generally stand on the right or off side of the batsman at long off, cover point, short slip long slip and square mid-on and long-on, The man behind the wicket is cal...
Read more

Islamic Way Of Life - Paragraph

Image
Islamic way of life is the complete beneficial way of life. Islamic way of life is necessary for all the nations. The nation can change the sorrows, darkness and drwabacks into happiness and prosperity with the help of Islamic way of life. Islamic way of life provides the better guidance in every aspect of life. Islamic way of life makes us true Muslim, confident, honest, man of priniciple, incorrupt, selfless, literate and paintaking. Now a days an Islamic of life is an essential code of life in the world. Everywhere we dupes, corruption, blind, fath, sins, disobediency, husmoney, murders and terorism increasing day by day. Therefore, its necessary to establish an Islamic, one unit Government system for the whole nation where we can get the rid of every end of evil. I like the most an Islamic way of life than other government system. We should establish an Islamic government as own unit system. We should act upon the Islamic teaching.
Read more