Below are the choices:
a. −166 kJ/mol
<span>b. 166 kJ/mol </span>
<span>c. 1.64 kJ/mol </span>
<span>d. 1.66 × 10^5 kJ/mol
</span>
To calculate the activation energy of a reaction, we use the Arrhenius equation. You may want to look it up to see how and why it works. In the problem you posted, there are two temperatures and two rate constants. After some rearranging and substitution of the Arrhenius equation, we have Ea = R T1 T2/(T1-T2) ln(k1/k2) = 8.314 J/mol K (600 K)(650 K)/(600 K-650 K) ln(2.7×10^-4 M^−1sec^−1/3.5×10^−3 M−^1sec^−1) = 166145 J/mol = 166 kJ/mol => choice b
Answer:
It is called Asterism.
Explanation:
It is Asterism because Asterism refers to a pattern of stars that are seen in night sky and are very distinctive and identifiable. These group of starts have patterns. It visually seen collection of stars and it's indicate their properties and the lines that connect the stars together. It actually range from small shapes of stars to more complex stars that cover segment of the sky. The stars may be bright naked or have similar brightness.
Answer:
²⁵ Mg = 10.00%
²⁶ Mg = 11.0%
Explanation:
Given that:
Magnesium ²⁴Mg has an abundance of 78.99%
Hence, (100 - 78.99)% = 21.01%
21.01% is the abundance of ²⁵ Mg and ²⁶ Mg
Suppose,
²⁵ Mg = x
²⁶ Mg = (21.01 - x)%
Then;
avg. atomic mass = 
where the avg. atomic mass = 24.3050
∴
2430.5 = 2440.46915 -0.9968 x
0.9968x = 2440.46915 - 2430.5
0.9968x = 9.96915
x = 9.96915/0.9968
x = 10.00%
∴ Recall that:
²⁵ Mg = x
²⁶ Mg = (21.01 - x)%
²⁵ Mg = 10.00%
²⁶ Mg = (21.01 - 10.00)%
²⁶ Mg = 11.0%
Answer:
im getting 331.23
Explanation:
Element Number Mass Percet Composition
O 6 16.00 28.9828819853274
N 2 14.01 8.45937867946744
Pb 1 207.21 62.5577393352051
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
