We are given the mass spectrum data for this compound which has a molecular ion peak of m+ = 91.043 m/z. When we have an m+ peak that is an odd number, that suggests that there are an odd number of nitrogens, in this case we'll assume 1 nitrogen atom to start. Nitrogen has a mass of 14 so we will substract that from our initial value.
91- 14 (1N) = 77 m/z
We are also told that there are carbon, hydrogens and oxygens present, so we will assume there is at least one oxygen which has a mass of 16 and subtract that value.
77 - 16 (1 O) = 61 m/z
Now we will try to get as close as possible to the remaining mass with carbons that has a mass of 12, and fill the remaining mass with hydrogens that have a mass of 1.
61 / 12 = 5
5 x 12 = 60
61 - 60 (5 C) = 1 m/z and this leaves us with 1 H.
The current formula would be C₅HON, but this structure is impossible since we do not have enough hydrogens to satisfy the carbons. So we can try to use 4 carbons instead and fill the rest with hydrogens.
4 x 12 = 48
61 - 48 (4 C) = 13 m/z and this leaves us with 13 H.
The current formula would be C₄H₁₃ON. The most hydrogens we can have in a compound is 2n+2 where n is the number of carbons. So with 4 carbons the most hydrogens we could have is 10. Therefore, our formula has too many hydrogens and also cannot work. So we cannot make up the remaining mass with carbons and hydrogens, therefore, we should add another oxygen before working with carbons and hydrogens.
61 - 16 (1 O) = 45 m/z
45/ 12 = 3.75
3 x 12 = 36
45 - 36 (3 C) = 9 m/z which gives us 9 hydrogens left.
The current formula is now C₃H₉O₂N. To test if this formula works we can calculate the double bond equivalents (DBE), also known as degrees of unsaturation.
DBE = C - H/2 + N/2 + 1 = 3 - (9/2) + (1/2) + 1 = 0
A value of 0 DBE tells us that there are no double bonds in this molecule but that the formula is a possibility so:
C₃H₉O₂N = 91 m/z
The moles are used to determine the atoms and molecules in a substance. It is used by chemists to determine the amount of reactants needed and products produced. Thus, option B is correct.
<h3>What are moles?</h3>
A mole is said to be defined as the estimation of the small entities like the atoms as that of the Avagadro's number 6.022 × 10²³. It defines the number of particles contained in a substance.
The moles of the substances are determined by the mass of the substance and its molar mass. The moles are given as,
Moles = mass ÷ molar mass
The moles give the estimation of the amount of the reactants needed to produce the products in a chemical reaction.
Therefore, option B. the moles tell the amount of the reactants required to produce the product.
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The values of the changes are
ΔH = 46.44kJ
Δu = 43.34Kj
ΔS = 126.6 J/K
<h3>How to find change in H</h3>
= 1 mol + 75.3 (100 + 273) - 25 + 273 + 1 * 40.79
= 5.6475 + 40.79
= 46.44kJ
<h3>How to find change in S</h3>
1 mol + 75.3 x ln 373/298 + 1 mol x 40.79
= 0.1263
ΔS = 126.6 J/K
<h3>How to find the change in U</h3>
46.44 - 0.00831 * 373
= 43.34Kj
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The smallest unit of an element that retains the chemical and physical properties of an element is an Atom.
Determine the mass of each of the following amounts. a. 1.366 mol of
NH3
, b. 0.120 mol of glucose,
C6H12O6
, c. 6.94 mol barium chloride,
BaCl2
, d. 0.005 mol of propane,
C3H8
