Answer:
To solve this problem, you need to follow these steps:
(a) To find the chemical formula of the salt, you need to determine the empirical formula of the anion and then combine it with the sodium cation. To do this, you need to calculate the moles of C, H, and O in the anion from the given masses of CO2 and H2O. Then, you need to divide the moles by the smallest value to get the simplest ratio of the elements. Finally, you need to multiply the ratio by a factor to get the whole number of atoms that matches the given molar mass of the salt.
Using this method, the calculation can be done as follows:
Moles of C in the anion = (0.942 g CO2) / (44.01 g/mol CO2) x (1 mol C / 1 mol CO2) = 0.0214 mol C
Moles of H in the anion = (0.0964 g H2O) / (18.02 g/mol H2O) x (2 mol H / 1 mol H2O) = 0.0107 mol H
Moles of O in the anion = (0.942 g CO2) / (44.01 g/mol CO2) x (2 mol O / 1 mol CO2) + (0.0964 g H2O) / (18.02 g/mol H2O) x (1 mol O / 1 mol H2O) = 0.0535 mol O
Simplest ratio of C, H, and O in the anion = (0.0214 / 0.0107) : (0.0107 / 0.0107) : (0.0535 / 0.0107) = 2 : 1 : 5
Factor to get the whole number of atoms = (112.02 g/mol) / [(2 x 12.01 g/mol) + (1 x 1.01 g/mol) + (5 x 16.00 g/mol)] = 1
Empirical formula of the anion = C2H1O5
Chemical formula of the salt = NaC2H1O5
Therefore, the answer is NaC2H1O5.
(b) To draw the Lewis structure of the anion, you need to count the total number of valence electrons, arrange the atoms around the central atom, connect them with single bonds, and distribute the remaining electrons to satisfy the octet rule. To do this, you need to know that carbon has 4 valence electrons, hydrogen has 1, and oxygen has 6. You also need to know that the salt contains carboxylate groups (CO2-), and the carbon atoms are bonded together.
Using this method, the drawing can be done as follows:
Total number of valence electrons = (2 x 4) + (1 x 1) + (5 x 6) + 1 = 40
Arrangement of atoms = C-C-O-O-O-H
Single bonds = C-C-O-O-O-H | | | |
Remaining electrons = 40 - 12 = 28
Distribution of electrons = C-C-O-O-O-H | | | | … … … … … … … …
Therefore, the Lewis structure of the anion is:
O- O- O
// | \\
C-C-O-H ..
| | | ..
.. .. ..
To determine the acidity or basicity of the dissolved substance, you need to identify the conjugate acid-base pairs and compare their relative strengths. To do this, you need to know that the salt is the product of a weak acid (C2H2O5) and a strong base (NaOH). You also need to know that the carboxylate groups can act as weak bases and accept protons from water, forming bicarbonate and carbonate ions. You also need to know that the given Ka values are the acid dissociation constants of the weak acid and its conjugate base.
Using this method, the analysis can be done as follows:
Conjugate acid-base pairs = C2H2O5 / C2H1O5- and C2H1O5- / C2O5(2-)
Relative strengths = C2H2O5 is a weak
Step-by-step explanation: