# unit conversion

• May 20th 2008, 07:54 PM
hockeyplayer
unit conversion
I was wondering if you all could help me with my dimensional analysis problems. I am having a major problem with these and can't seem to get them to come out right. I know it's that I'm not setting up the problems in the right way so if anyone could help me I'd appreciate it.

if I wanted to convert 1.25 deciliters into nanoliters how would I accomplish this?
the only way I can think of is to first convert deciliters into liters then jump right into nanoliters. I guess it looks something like this.

1.25 deciliters x 1 liter x 1,000,000 nanoliters
10 deciliters 1 liter

I make sure that my units match up so I can cancel them, but I don't think that the problem is coming out right. As far as I know there are 100,000 milliliters in a liter and 1,000,000 nanoliters in a liter. if that's not correct plz tell me b/c that might be the problem.

my next question is would there be 3 significant figures in the final answer b/c of the 1.25? I believe that you would round off the answer if the 4th digit is 5 or higher.

I am good at the basic ones. I can pretty much figure them out, but the ones that involve more than one conversion I have problems with. could anyone plz give me some helpful hints in solving these problems plz?

thank you all for your time.
• May 21st 2008, 01:40 AM
Dimensional Analysis
You have dL = 1/10 L, which is true, but
nL = (1/1,000,000,00)L or 10^-9 L (not 10^-6)
and
mL = (1/1,000)L or 10^-3 L (not 10^-5)
If you got these wrong, you would be lost from the start.

-----------------------------------------
The number of significan digits in the result of a calculation can have only as many significant digits as the number with least number of significant digits that was used in the calculation.

You can probably find some examples in a special section on measurement or even a section titled "signficant figures" in many texts on chemistry and physics, or you could go online and find it quicker.
-----------------
Significant Digits, the problem of zeros:
-------------------------------------
A zero between two other digits is always significant.

Zeros to the left of all nonzero digits are not significant, i.e., leading zeros are not significant.

Zeros right of the decimal point and to the right of nonzero digits are significant.

Zeros on integers may or may not be significant, depending on the accuracy of the measurement from which the number was derived.