Question

SIGNIFICANT FIGURES....

Having a moment. So if I have 2.00x10^-3M (.005L) =1x10^-5 M. The SF here would be 1, hence why the answer is 1 and not 1.0, correct?

Or, does this go back to converting 5.0mL to L? should i be multiplying by (.0050L) rather than (.005L)?

Thus farther, if I'm taking that number from the first equation and subtracting a second....

1x10^-5 - 2.6x10^{-7 =} 9.74 x 10^-6  

What is the correct number of SF in the second equation??? Should it be one? and then what does it round to then?

Sorry, just royally confused on this lab that has roughly 75 of these calculations. Want to make sure my SF are accurate! Thank you!

Answer 1

2.00x10^-3 has 3 significative figures, and 0.005 has 1. When you multiply or divide numbers, the number of significative figures of the result is the number of significative figures of the number with the fewest.

In this case 0.005 has 1 significative figure, so the result must have 1 significative figure. That is why 1 is correct and not 1.0.

When an addition or substraction is done the number of digits after de decimal point is equal to the number of digits after the decimal point of the number who has fewer.

1x10^-5 doesn´t have digits after the decimal point, so the result will have 0 digits after the decimal point.

so the result will be also 1x10^-5