The tip of a match is ignited as it is struck against the matchbox. Why is this a chemical change? a.The color of the match tip
2 answers:
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Answer:
a) 1,6%
b) 64,775 g/mol
c) 3,6×10⁻² M
d) 2,3×10⁻³ g/mL
Explanation:
a) The mass fractium of helium is obtained converting the moles of the four gases to grams with molar weight and then caculating of the total of grams how many are of helium, thus:
- Helium: 0,25 moles ×
= 1 g of Helium
- Argon: 0,25 moles ×
= 10 g of Argon
- Krypton: 0,25 moles ×
= 20,95 g of krypton
- Xenon: 0,25 moles ×
= 32,825 g of Xenon
Total grams: 1g+10g+20,85g+30,825g= 62,675 g
Mass fraction of helium: × 100 = <em>1,6%</em>
<em />
<em>The mass fraction of Helium is 1,6%</em>
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<em>b)</em><em> </em>Because the mole fraction of all gases is the same the average molecular weight of the mixture is:
= 64,775 g/mol
c) The molar concentration is possible to know ussing ideal gas law, thus:
= M
Where:
P is pressure: 150 kPa
R is gas constant: 8,3145
T is temperature: 500 K
And M is molar concentration. Replacing:
M = 3,6×10⁻² M
d) The mass density is possible to know converting the moles of molarity to grams with average molecular weight and liters to mililiters, thus:
3,6×10⁻² ×
×
=
2,3×10⁻³ g/mL
I hope it helps!