Answer:
Empirical formula (which matches the molecular formula) is = PbC₈H₂₀
Explanation:
Our sample: 60 g of tetraethyl lead
In order to determine the compound empirical formula we need the centesimal composition:
(Mass of element / Total mass) . 100 =
(38.43 g lead / 60g ) . 100 = 64.05%
(17.83 g C / 60g) . 100 = 29.72%
(3.74 g H / 60g) . 100 = 6.23 %
These % are the mass of the elements in 100 g of compound. Let's find out the moles of them:
64.05 g / 207.2 g/mol = 0.309 moles
29.72 g / 12 g/mol = 2.48 moles
6.23 g/ 1 g/mol = 6.23 moles
Next, we divide the moles, by the lowest value of them (0.309)
0.309 / 0.309 = 1 mol Pb
2.48 / 0.309 = 8 mol C
6.23 / 0.309 = 20 mol H
There, we have our formula PbC₈H₂₀
Answer:
d) Interaction between Arg and Lys side chains at a pH of 7, assuming standard pKa values for Arg and Lys.
Explanation:
Arginine and Lysine are basic amino acids. They play same role in various membrane proteins. They both have high aqueous values which give rise to high electrostatic interaction. The interaction is mainly in the cations of the side chains. They both are heterologous secreted proteins which plays role of metabolite.
The mole ratio of acetic acid to water in 100 g of vinegar is 0.015 : 0.985.
<h3>What is the mole ratio of acetic acid to water in 100 g of vinegar?</h3>
The mole ratio of acetic acid to water in 100 g of vinegar is determined from their percentage composition.
The percentage composition of acetic acid and water in vinegar is 5% acetic acid and 95% water.
In 100 g of vinegar, there are 5 g of acetic acid and 5 g of water.
Moles = mass/molar mass
molar mass of acetic acid = 62 g/mol
molar mass of water = 18 g/mol
moles of vinegar = 5/62 = 0.08
moles of water = 95/18 = 5.28
total moles = 5.36
Mole ratio of vinegar to water = 0.08/5.36 : 5.28/5.36
Mole ratio of vinegar to water = 0.015 : 0.985
In conclusion, the mole ratio is determined from the percentage composition of acetic acid and water in vinegar.
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There are no above options to choose from so I am giving an example of a X3Y2 formula which is Magnesium nitride, the formula is Mg3N2.
