<p>You have two distinct gaseous compounds made from element X and element Y. The mass percents are as follows: </p>
<p>Compound 1 : 30.43% X, 69.57% Y
Compound 2 : 63.64% X, 36.36% Y</p>
<p>In their natural standard states, element X and element Y exist as gases. (Monatomic? Diatomic? Triatomic? That is for you to determine.) When you react "gas X" with "gas Y" to make the products, you get the following data (all standard pressure and temperature.) </p>
<p>1 volume "gas X" + 2 volumes "gas Y" -> 2 volumes compound 1
2 volumes "gas X" + 1 volume "gas Y" -> 2 volumes compound 2</p>
<p>Assume the simplest possible formulas for reactants and products in the chemical equations above. Then, determine the relative atmoic masses of element X and element Y.</p>
<p>Please help... i know this is simple beginners stuff but i forgot how to do it and cant find it in the book so please explain this to me. Thank you.</p>
<p>bumb... no1 knows how?</p>
<p>O Cmon, Nobody Wants To Help Me??</p>
<p>here's my take on this:</p>
<p>given the percentage by mass of both elements, assume you have 100g of each compound. then</p>
<p>30.43g X and 69.57g Y from compound 1
63.64g X and 36.36g Y from compound 2</p>
<p>knowing the fact that dividing grams by the molecular mass gives the number of moles of any element:</p>
<p>30.43/A + 2(69.57/B) = 2(100)/(A+B)
2(63.64/A) + 36.36/B = 2(100)/(A+B)</p>
<p>where A is the molecular mass of X and B the molecular mass of Y...</p>
<p>i guess th atomic masses will just be the answers except with "amu" as the units...</p>
<p>i'm actuallly really skeptical about my answer but gave it a try anyways... someone help out here now i'm curious!</p>
<p>i dont understand that :[. I dont think your answer is correct because i didnt learn anything like that at all. I just forgot how to do it because i learned it so long ago but i wont discredit you for your effort, it might jsut be another way of solving it.</p>
<p>This seems a bit more complex than any stoich problem I ever encountered in ap chem, but I'll give it a go.</p>
<p>Let's assume that a unit of compound 1 is 100g and a unit of compound 2 is 100g... in other words, compound 1 will be 30.43g X and 69.57g Y, and compound 2 will be 63.64g X and 36.36g Y.</p>
<p>According to the information given in your problem, we can also write the following two chemical equations:
X+2Y--> 2(compound 1)
2X+Y--> 2(compound 2)</p>
<p>Using the 100g unit I described above, we can also write this as:
X+2Y--> 2(30.43g X) + 2(69.57g Y)
2X+Y--> 2(63.64g X) + 2(36.36g Y)</p>
<p>We add these two chemical equations together and get:
3X+3Y--> 2(30.43g+63.64g X) + 2(69.57g+36.36g Y)</p>
<p>This can be written more simply as:
3X+3Y--> 188.14g X + 211.86g Y</p>
<p>In other words, 3 volumes of X gives 188.14g of X, and 3 volumes of Y gives 211.86g of Y. Divide each one by 3 to find out how much is in one volume, and you get 62.71g per volume X, and 70.62g per volume Y. Since you're told that it's at standard temp/pressure, we can assume that one volume is one mole, and our final answers would be:
X: 62.71 g/mol
Y: 70.62 g/mol</p>