Mole percent of O2 = 10% = 0.1 moles
Mole percent of N2 = 10% = 0.1 moles
Mole percent of He = 80% = 0.8 moles
Molar Mass of O2 = (2 x 16) x 0.1 = 3.2
Molar Mass of N2 = (2 x 14) x 0.1 = 2.8
Molar Mass of He = 4 x 0.8 = 3.2
1. Molar Mass of the mixture = 3.2 + 2.8 + 3.2 = 9.2 grams
2. Since at constant volume density is proportional to mass, so the ratio of
mass will be the ratio of density.
Ratio = Molar Mass of the mixture / Molar Mass of O2 = 9.2 / 32 = 0.2875
I believe the complete
given is that the bucket of sand contains 9.5 billion grains of sand. That is:
bucket = 9,500,000,000
grains
and the concentration of
brown sand is 2 ppm:
concentration brown sand =
2 / 1,000,000
Therefore:
brown sand = 9,500,000,000
* (2 / 1,000,000)
<span>brown sand = 19,000 grains</span>
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Below are the choices that can be found from other sources.
The answer is C endothermic and exothermic
<span>a. exothermic and exothermic
b. exothermic and endothermic
c. endothermic and exothermic
d. endothermic and endothermic</span>
