Answer:
The minimum number of boxes of pencils to be ordered is 630 boxes.
Explanation:
Since a pupil uses averagely 9.3 pencils
and a box contains 12 pencils,
the school enrollment is also 812
school's enrollment x average use of pencil per student
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number of pencils in a box
812 x 9.3 = 7551.6
7551.6 /12 = 629.3
Having a total number of 630 boxes of pencils to be ordered.
Answer:
B. humus
Explanation:
Humus is the exponent of soil.
The ozone layer protects humans from harmful UV rays, because it acts as a sort of filter for any toxic or overpowering waves from damaging our skin. This goes for animals, as well.
1) Excess reagent
1 mol N2 / 3 mol H2
6.0 mol N2 *3 mol H2 / 1 mol N2 = 18 mol H2
18mol H2 > 12 mol H2 => H2 is limiting (you need 18 mol H2 to use all the 6 mol N2), then N2 is in excees.
12.0 mol H2 * 1mol N2/ 3 mol H2 = 4 mol N2 is the quantity that will react, then the excess is 6 mol N2 - 4 mol N2 = 2 mol N2
2) NH3 produced
12 mol H2 * [2 mol NH3 / 3 mol H2] = 8 mol NH3
Aslso, 4 mol N2 *[2molNH3 / 1 molN2] = 8 mol NH3, the same result.
3) Yield
80% * 8 mol NH3 = 6.4 mol NH3