Hard Stoichiometry Problem

Test Preparation AP Test Preparation
1

<p>My AP Chemistry teacher said this is one of the most difficult stoichoimetry problem that we, as students, will ever encounter. He said if we can figure out the answer to this problem, he will reward us with adding points on our past test.
Here is the problem:</p>

<p>The space shuttle environmental control system handles carbon dioxide (4% by mass exhaled air) by reacting it with Lithium Hydroxide pellets to form lithium carbonate and water. If there are 7 astronauts on board the shuttle, and each exhales 20 liters of air per minute, how long could clean air be generated if there were 25,000 g of lithium hydroxide pellets avaliable for each shuttle mission? Assume the density of air is 0.0010 g/mL.</p>

2

<p>first you balance the equation:
CO2+2Li(OH)-->Li2(CO3)+H2O</p>

<p>so it's 20L/min of air per passenger so that's 20*7 gives you 140L/min and then you find 4% of that which is 5.6L/min CO2. then you make a stoich table:</p>

<p>5.6L CO2/min * 1000mL/1 L * 0.0010g CO2/1 ml * 1 mol CO2/44.0g </p>

<ul>
<li>2 mol LiOH/1 mol CO2 * 23.9 g/1 mol LiOH * 1/25000g</li>
</ul>

<p>so then you multiply all the top and divide by all of the bottom and get: 2.43e-4 min^-1 (minutes are on the bottom) so just inverse that and you get 4109 minutes and that should be the answer.</p>

3

FUCK STOICHIOMETRY