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.
<span>0.06355391 mol
The balanced equation for the reaction is
Na2B4O7*10H2O + 2 HNO3 = 2 NaNO3 + 4 H3BO3 + 5 H2O
So for each mole of Borax to neutralize, it takes 2 moles of HNO3.
Calculate number of moles of Borax
0.2619 g / 381.372 g/mol = 0.0006867 mol
Moles of HNO3 used = 0.0006867 mol * 2 = 0.0013734 mol
Molarity is defined as moles per liter so divide the number of moles used by the volume in liters. So
0.0013734 / 0.02161 = 0.06355391 mol</span>
I think it is C because photosynthesis converts solar energy
