<p>I have a test tomorrow and I really need help on redox and other stuff that I can't categorize. </p>
<p>Could someone please tell me the steps I need to do in order to solve this problem? ( i can't use calculators for these problems )</p>
<p>What mass of styrene (molar mass 104.1) will contain 4.50 x 10^20 molecules of styrene?</p>
<p>a) 7.48 x 10^-4 g
b) 7.48 x 10^-3 g
c) 7.78 x 10^-2 g
d) 7.48 x 10^4 g</p>
<p>[Solution uses XeY to denote X * 10^Y]</p>
<p>4.50e20 molecules * 1 mol / 6.022e23 molecules * 1.041e2 g / 1 mol = 7.78e-2 g</p>
<p>Since you can't use the calculator, getting the final answer is rather burdensome, but you can easily reason out the exponents which narrows you down to the right answer. Roughly: 5e20/6e23=.8e-3=8.e-4 and 8.e-4/1e2=8e-2</p>
<p>sorry
i dont know
:/</p>
<p>I thought you aren't allowed to post homework help? Are they enforcing that policy? I the admins aren't, then I might as well ask away.</p>
<p>[sorry for not helping you, i don't know]</p>
<p>use the magic of exponents to estimate your answer! (i hope you know how to do the problem this fart into the school year in AP Chem)</p>
<p>Wait, wait, wait, is it just me or was this post bumped up three and a half years?!</p>
<p>ahahahahaha</p>
<p>great bump</p>
<p>i didnt think people would have been confused</p>
<p>LOL jmarin gj.</p>
<p>thank you echelon
you get a gold star in my book</p>
<p>LOL @ this post.</p>
<p>well anyways, to do this easily w/o calculator (cuz i'm bored)</p>
<p>MM (styrene) ~= 100 g/mol
n (# molecules of styrene) ~= 4.5e20
N_a (avocado's #) ~= 6e23</p>
<p>n / N_a = n (moles of styrene) ~= 3/4 e-3
MM * n ~= 100 * 3/4 x 10^-3
~= 7.5e-2 g</p>
<p>so the answer is B</p>
<p>this was possibly a small waste of time...given that the answer was given above...</p>
<p>Given that the author probably has long since passed away and is now in [s]mental[/s] institution of higher education.</p>
<p>get banned another way freak</p>