We know that:
number of moles (n) = mass / molar mass
Now, from the general law of gases:
PV = nRT
where:
P is the pressure = 500 torr = 0.65 atm
V is the volume
n is the number of moles
R is the gas constant = 0.082
T is the temperature = 300 k
We will just rearrange this equation as follows:
P = nRT / V
Then we will substitute n with its equivalent equation mentioned at the beginning:
P = (mass x R x T) / (volume x molar mass) ......> equation I
Now, we know that:
density = mass / volume
We will substitute (mass/volume) in equation I with density as follows:
P = (density x R x T) / molar mass
Rearrange this equation to get the mass as follows:
molar mass = <span>dRT/P = (0.216 x 0.082 x 300) / 0.65 = 8.4738 grams
</span>
From the periodic table:
molecular mass of hydrogen = 1 grams
molecular mass of nitrogen = 14 grams
Therefore:
molar mass of hydrogen = 2 x 1 = 2 grams
molar mass of nitrogen = 2 x 14 = 28 grams
We can assume that the number of moles of of each element is y.
We can thus build up the following equation:
2y + 28y = 8.4738
30y = 8.4738
y = 0.28246
Therefore:
mole fraction of hydrogen = 2 x 0.28246 = 0.56492
mole fraction of nitrogen = 28 x 0.28246 = 7.90888
Percent yield is 23.11 % when 162.8 g of CO2 are formed from the reaction of excess amount of C8H18 and with 218.0 grams of O2.
Explanation:
Balanced equation for the chemical reaction:
2C8H18 + 25O2 → 16CO2 + 18H2O
data given:
CO2 formed (actual yield) = 162.8 grams
mass of oxygen = 218 grams
16 moles of CO2 formed when 5 moles of oxygen reacted
3.6 moles of CO2 formed when 6.8 moles of oxygen reacted.
In the reaction 16 moles of CO2 will have 44.01 x 16
theoretical yield of CO2 = 704.16 grams
percent yield = 
x100
putting the values in the above equation
percent yield = 
x 100
= 0.23 x 100
= 23.11 %
Percent yield is 23.11 %.
Speed of light = freq * wavelength
<span>wavelength = speed of light / freq = (3*10^8 m/sec ) / (2.6 * 10^9 /sec) = 1.15 * 10^(-1) m </span>
<span>1.15 * 10^(-1) m *(10^9 nm / m) = 1.15 * 10^8 nm</span>
The wave length decreases
