Question about Office Equipment & Supplies
It's the atomic mass of an element, namely protons AND neutrons usually denoting an isotope. It is only the protons that define the chemical properties (and hence name) of an element. Examples Uranium 235 (fairly common) and Uranium 238 (rare). Only about 1% of natural Uranium is U-238 - that's why Uranium enrichment plants exist - to extract U-238 for power stations and (unfortunately) weapons.
Posted on May 27, 2014
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Oct 17, 2013 | InnerIntimates Vaginal Renewal Complex...
Jul 22, 2011 | NEC SuperScript 1400 Laser Printer
Mar 19, 2011 | Computers & Internet
The calculated moles of C = [grams C] / [MW of C] = [188 g C / 12.0 g] = 15.7 mol C
Therefore, there are 15.7 moles of O2, as calculated from use of the math expression (with boxes) shown above.
The wanted GRAMS of O2 are calculated from MW of O2 times its number of moles, as follows:
Grams of O2 = 32.0 g O2 x 15.7 mol O2 = 502 grams O2.
For your convenience as you make conversions among grams and moles, you may use the following memory aid:
To go from moles to grams, just notice that moles are beside MW, so multiplying them will give grams (moles x MW = grams). If you want to go from grams to moles, notice that grams are over MW, so (grams/MW) = moles. If you should want to calculate MW, you would divide grams by moles, (grams/moles) = MW.
One more tip: When doing calculations, use at least the same number of significant figures (sig figs) in the molecular weights (and atomic weights) as is in the given numerical data. That is, since there are three sig figs in 188 grams of C, use 12.0 as the atomic weight of C, and 44.0 as the MW of CO2. You would obtain the same answer using 12 and 44, but as you may know, following this rule would be more important in other problems in which the digit past the decimal is not zero. This allows proper rounding off of the final calculated quantity.
Suggestion: Try out this method to other problems involving a chemical reaction. Good luck!
Dec 12, 2010 | Scientific Explorer My First Chemistry Kit
Oct 26, 2010 | Computers & Internet
Sep 06, 2010 | Casio FX-115ES Scientific Calculator
76 people viewed this question
Usually answered in minutes!