Determining the molecular formula of a hydrocarbon with a relative molecular mass of 54
1 answer:
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<h3>Answer:</h3>
Longest wavelength = 343.7 nm
<h3>Solution and Explanation:</h3>In this question we need to first use the concept of energy of a photon.
Energy of a photon, E, is given by the formula, E = hf, where h is the plank's constant, f is the frequency.
But since, f is given by dividing speed, c, by wavelength, λ, then;
E = hc/λ
We are given 348 kJ/mol required to break carbon-carbon bonds.
We know that; 1 mole of bonds = 6.022 × 10^23 bonds.
We are required to find the longest wavelength with enough energy to break the C-C bonds.
This can be worked out in simple steps:
Step 1: Energy required to break one bond (kJ/bond)
1 mole of bonds = 6.022 × 10^23 bonds.
Therefore;
348 kJ = 6.022 × 10^23 bonds.
Thus;
1 bond = 348 kJ ÷ 6.022 × 10^23 bonds.
= 5.778 x 10^-22 kJ
But; 1000 joules = 1 kJ
Hence; energy per bond = 5.778 x 10^-19 Joules
Step 2: Energy per photon
Breaking one bond requires energy equivalent to energy of a photon.
Therefore;
1 photon = 5.778 x 10^-19 Joules
= 5.778 x 10^-19 J/photon
Step 3: Calculating the wavelength
From the equation of energy of a photon;
E = hc/λ
h is the plank's constant = 6.626 × 10^-34 J/s
c is the speed of light in vacuum = 2.9998 × 10^8 m/s
E is the energy of a photon = 5.778 x 10^-19 Joules
Therefore, making λ (wavelength) the subject;
= 3.437 x 10^-7 m
But; 1 nm = 10^-9 m
Thus;
wavelength = 343.7 nm
Therefore, the longest wavelength of the radiation will be 343.7 nm
Answer:
Option C. 2,2-dimethyl-1-propanol
Explanation:
The first attached picture, is the initial reactant.
Now, what happens in each step?, at first we have an alkyl bromide reacting with Mg/ether. This converts the reactant in a grignard reagent, which is often used in several ketones/ladehydes reactions, and even some acid and esthers.
Now, in the second step, we see this grignard reagent, reacting with CO₂ and H₃O⁺. At first, the grignard reagent will attach to the oxygen of the CO₂ by the MgBr, and the carbonated chain will attach to the carbonile. Then in acid medium, the OMGBr leaves the molecule, and form a carboxylic acid.
Finally, in the last step with LiAlH₄ and water, this compound just reduces the carboxylic acid to a primary alcohol, therefore, the only choice available is option c, 2,2-dimethyl-1-propanol.
See picture 2 below for the drawing.
Hope this helps
Answer : Option C) Atomic Size
Explanation : The atomic radius of the elements is found to be decreasing if we go from left to right in the modern periodic table. Accordingly, increases as the number of shielding electrons present in the atomic nucleus of the periodic elements which lies in the same row remains constant while the number of protons in each atomic shell increases.
The effective nuclear charge of an atom is defined as the net positive charge which is felt by the valence electron of the atomic element.
When is observed to decrease, it is seen that the atomic radius grows in size. So, it explains the inverse relationship between both. This phenomenon occurs, because there is more screening of the electrons from the nucleus taking place, which is observed due to decrease the attraction between the electron and the nucleus.