Answer:
D. 18,800 J/mol
Explanation:
We need to use the Arrhenius equation to solve for this problem:
, where k is the rate constant, A is the frequency factor, 
is the activation energy, R is the gas constant, and T is the temperature in Kelvins.
We want to find the value of , so let's plug some of the information we have into the equation. The gas constant we can use here is 8.31 J/mol-K.
At 0°C, which is 0 + 273 = 273 Kelvins, the rate constant k is 
. So:
At 20°C, which is 20 + 273 = 293 Kelvins, the rate constant k is 
. So:
We now have two equations and two variables to solve for. We just want to find Ea, so let's write the first equation for A in terms of Ea:
Plug this in for A in the second equation:
After some troublesome manipulation, the answer should come down to be approximately:
Ea = 18,800 J/mol
The answer is thus D.
Answer:
C) 4.
Explanation:
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In this case, since the electron configuration of nickel at its ground-state, considering 28 as its atomic number and the number of electrons it has in one atom, is:
We can see it has four energy levels, 1, 2, 3 and 4, which are related to the following principal quantum number, that describes the energy of an electron in the atom and its most probable distance with respect to the nucleus.
Therefore, nickel has C) 4 different principal quantum numbers.
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V = f 入 (velocity = frequency x wavelength)
<span>If we have the speed ( for wave in vacuum </span><span>i.e. 3 x 10^8 m/s) </span>
<span>Then the frequency of x-ray is </span>
<span>(3 x 10^8) ÷(1.15 x 10^-10) = 2.61 x 10^18 </span>
Answer:
The neutron is 30
Explanation:
The element with atomic number of 25 is Manganese. it has a mass number of approximately 55.
Therefore, the neutron number = Mass number - Proton number (i.e. atomic number)
= 55 - 25
Neutron number = 30
- <span>Graduated cylinders are used to measure volume.
- </span><span>Always read a graduated cylinder from the bottom of the meniscus.</span>
