To answer this item, we assume that the gases are ideal for us to be able to use the ideal gas law.
PV = nRT
where P is pressure, V is volume, n is the number of moles, R is the universal gas constant and T is the temperature (in K)
Substituting the known values,
(0.963 atm)(6.92 L) = n(0.0821 L.atm/mol.K)(298 K)
The value of n from the equation is n = 0.27237 moles
We let x and y be the number of moles of NO2 and N2O4, respectively. Given the calculated total moles above and the total mass,
x + y = 0.27237
30x + 60y = 12.55
The values of x and y are:
x = 0.126 moles
y = 0.146 moles
The mole fractions of each gases are therefore:
mole fraction of NO2 = 0.126/(0.126 + 0.146) = 0.46
mole fraction of N2O4 = 0.146/(0.126 + 0.146) = 0.54
<span>(2) butynu........................</span>
<span>C. Jewelry tarnishing is an example of a chemical change.
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Chemical change is a process where a current substance changes or is made into a new type of substance<span>. Unlike the physical change, which is reversible. Chemical change stays into a its new form. Take for instance these -physical change- examples, making ice cubes. The process involves solidification or freezing where the water becomes ice or solid but when it melts back to its original or typical form with respect to temperature, it’s still water. When the paper is cut into pieces it isn’t burned or exposed to a stimuli that can trigger immediate change in its composition. It’s still the same. On the contrary, baking a cake involves these different compositions or substances –flour, egg, yeast and etc. that is baked to a cake, a newly formed unified substance of all the included ingredients. <span> </span></span>
Fluorine is identified as the most reactive nonmetal and the most electronegative element in the periodic table, making it the strongest oxidizing agent.
Caesium is the most reactive metal in the periodic table, so much that working with this metal often ends in explosions!