Monday

June 29, 2015

June 29, 2015

Posted by **Mandy** on Monday, July 21, 2008 at 4:50pm.

A. 8.43 cm to millimeters--- 84.3 millimeters.

B. 2.41x10^2 cm to meterss--- 0.0241 meters.

C. 294.5 nm to centimeters--- I don't know how to concert this.

D. 1.445x10^4 m to kilometers--- 0.001443 Kilometers.

E. 235.3 m to millimeters--- 235300 millimeters.

F. 903.3 nm to micrometers-- I don't know hot to convert this.

Can anyone also tell me what "nm" means?

Thanks!

- Chemistry -
**DrBob222**, Monday, July 21, 2008 at 6:04pmA. 8.43 cm to millimeters--- 84.3 millimeters.

**OK**

B. 2.41x10^2 cm to meterss--- 0.0241 meters.**No. Don't let the exponent get to you. In simpler ones, as in this one, remove the exponent first to obtain 2.41 x 10^2 = 241 cm and divide by 100 to convert to meters = 2.41 meters.**

C. 294.5 nm to centimeters--- I don't know how to concert this.**1 nm = 1 nanometer = 1 x 10^-9 meter. The easiest way to convert all of these is to change everything to meters and go from there. There are 1 x 10^9 nm = 1 meter and 100 cm = 1 meter so**

294.5 nm x (1 m/1 x 10^9 nm) x (100 cm/1m) = 2.945 x 10^-5 cm. Notice how the units cancel. The first factor converts nm to m (see the nm unit cancels and leaves m); the second factor converts to cm(see the m cancels and leaves cm).

D. 1.445x10^4 m to kilometers--- 0.001443 Kilometers.**I came out with 14.45 km. Check my work.**

E. 235.3 m to millimeters--- 235300 millimeters.**That't what I have.**

F. 903.3 nm to micrometers-- I don't know hot to convert this.**There are 1 x 10^9 nm in 1 m and there are 1 x 10^6 micrometers in 1 m.**

I came out with 0.9033 micrometers. Check my work.

Can anyone also tell me what "nm" means?**nm stands for nanometers. The n for nano and m for meter.***You should know the prefixes. Here is a site that gives ALL of the prefixes.*

http://physics.nist.gov/cuu/Units/prefixes.html

- Chemistry -
**Mandy**, Monday, July 21, 2008 at 6:27pmThank you so much!

Im still a little confuse on the nanometers.

on problem c im not sure how you ended up getting 2.945 x 10^-5 cm. Could you maybe explain a little more to me?

- Chemistry -
- Chemistry -
**DrBob222**, Monday, July 21, 2008 at 7:52pmC. 294.5 nm to centimeters--- I don't know how to convert this.

**1 nm = 1 nanometer = 1 x 10^-9 meter. The easiest way to convert all of these is to change everything to meters and go from there. There are 1 x 10^9 nm = 1 meter and 100 cm = 1 meter so**

294.5 nm x (1 m/1 x 10^9 nm) x (100 cm/1m) = 2.945 x 10^-5 cm. Notice how the units cancel. The first factor converts nm to m (see the nm unit cancels and leaves m); the second factor converts to cm(see the m cancels and leaves cm)

The above is your original question and my response. Here is the math part revisited.

294.5 nm x (1 meter/1 x 10^9 nm) x (100 cm/1 meter) =

294.5 x 1 x 10^-9 x 1 x 10^2 (note that the 1 x 10^9 in the denominator was moved to the numerator by changing the sign of 1 x 10^9 to 1 x 10^-9 and I changed the 100 to 1 x 10^2 just so everything would be in exponent form). To multiply exponents we add them so

294.5 x 10^-9 x 10^2 = 294.5 x 10^-7. However, we usually leave numbers in exponential form with the decimal point just after the first digit; therefore, we move the decimal to the left two places to make it 2.945 and we take two places away from the 10^-7 by making it 10^-5. Another way to see it is this:

294.5 x 10^-7 = 0.00002945 which is the decimal point moved to the left 7 places from its original site. Then we move it back to the right 5 places to get 2.945 and since we have moved it 5 spots, then we follow with the 10^-5 exponent.

- Chemistry -
**Mohammad**, Tuesday, September 2, 2008 at 1:41amThank you guys sooo much, this definately helped a lot!

- Chemistry -
**Marc**, Sunday, September 7, 2008 at 9:31pmITS THE ZUMDHAL BOOK!

- Chemistry -
**ariel buchholz**, Wednesday, August 28, 2013 at 10:52pm8.43 cm to mm