Table Giving Answer
Element Atomic mass % Amount
Mg_24 24 79 18.96
Mg_25 25 10 2.5
Mg_26 26 11 2.86
Total 24.32
Discussion
The method of calculation for this table, which was done in Excel (a spread sheet) is shown below. Assume that there is 100 grams of material of "pure" magnesium. What is it's mass?
<em><u>Sample Calculation</u></em>
The the sample atomic mass = 24
Mass = % * sample atomic mass
Mass = 79% * 24
Mass = (79/100) * 24
Mass = 18.96
<em><u>Note</u></em>
The other two elements are found exactly the same as the sample calculation.
Then all you do is add the 3 masses together.
Answer
The mass of Mg to 1 decimal place is 24.3 <<<< Answer.
Answer:
balanced equation mole ratio 5 2 mol NO/1 mol O2
10.00 g O2 3 1 mol O2/32.00 g O2 5 0.3125 mol O2
20.00 g NO 3 1 mol NO/30.01 g NO 5 0.6664 mol NO
actual mole ratio 5 0.6664 mol NO/0.3125 mol O2 5 2.132 mol NO/1.000 mol O2
Because the actual mole ratio of NO:O2 is larger than the balanced equation mole
ratio of NO:O2, there is an excess of NO; O2 is the limiting reactant.
Mass of NO used 5 0.3125 mol O2 3 2 mol NO/1 mol O2 5 0.6250 mol NO
0.6250 mol NO 3 30.01 g NO/1 mol NO 5 18.76 g NO
Mass of NO2 produced 5 0.6250 mol NO2 3 46.01 g NO2/1 mol NO2 5 28.76 g NO2
Excess NO 5 20.00 g NO 2 18.76 g NO 5 1.24 g N
Explanation:
The information that the coefficients of a balanced equation give about the reactants are to tell how many moles of reactants are needed and how many moles of product can be produced.
