MS. Watson's AP Chem Ch. 4

Explanation
CH3CH2OH (ethanol) is a nonelectrolyte when dissolved in water because it does not dissociate into ions. It is a covalent compound that forms intermolecular bonds with water molecules, but does not break apart into charged particles. Therefore, it does not conduct electricity in solution. On the other hand, ZnBr2, LiCl, and KOH are all ionic compounds that dissociate into ions when dissolved in water, making them electrolytes.

Explanation
Acetic acid (CH3CO2H) is a weak electrolyte when dissolved in water because it only partially ionizes into ions (H+ and CH3CO2-) in solution. This means that it conducts electricity to a lesser extent compared to strong electrolytes like sodium hydroxide (NaOH) and sodium acetate (NaCH3CO2), which completely dissociate into ions in water. Glucose (C6H12O6) is a non-electrolyte and does not dissociate into ions in water.

Explanation
Al(NO3)3 will have the highest concentration of dissolved ions because it dissociates into three Al3+ ions and three NO3- ions when dissolved in water. This means that for every mole of Al(NO3)3 dissolved, there will be a total of six moles of ions in solution. In contrast, HF only dissociates into one H+ ion and one F- ion, NaOH dissociates into one Na+ ion and one OH- ion, and MgSO4 dissociates into one Mg2+ ion and one SO42- ion. Therefore, Al(NO3)3 will have the highest concentration of dissolved ions.

Explanation
LiOH is soluble in water because it is a strong base. When it dissolves in water, it dissociates into Li+ and OH- ions, which are both capable of forming hydrogen bonds with water molecules. Mg(OH)2, Cu(OH)2, and Fe(OH)3 are not soluble in water because they are all weak bases. They do not dissociate completely in water and do not form enough ions to overcome the attractions between their ions and water molecules. Therefore, only LiOH is soluble in water.

Explanation
KNO3 and CuCl2 will be soluble in water because they are both ionic compounds. Ionic compounds generally dissolve in water due to the attraction between the positive and negative ions and the polar nature of water molecules. KNO3 is a salt formed from the combination of a metal ion (K+) and a nonmetal ion (NO3-), while CuCl2 is formed from a metal ion (Cu2+) and a nonmetal ion (Cl-). In contrast, Ca3(PO4)2 and Fe2S3 are insoluble in water because they are both compounds with low solubility in water.

Explanation
When aqueous AgNO3 is added to an aqueous solution of KI, a precipitate will form. This is because the reaction between silver nitrate (AgNO3) and potassium iodide (KI) forms insoluble silver iodide (AgI), which appears as a yellow precipitate.

Explanation
Adding Pb(NO3)2 to the aqueous solution of the white solid will allow you to distinguish between NaI and NaNO3. Pb(NO3)2 reacts with NaI to form a yellow precipitate of PbI2, while it does not react with NaNO3. Therefore, the formation of a yellow precipitate indicates the presence of NaI, distinguishing it from NaNO3.

Explanation
The given answer "I love it" suggests that the person enjoys and has a strong liking for the chapter. They find it interesting and engaging, possibly due to the content or the way it is presented. This positive attitude towards the chapter indicates a high level of interest and enthusiasm, making it easier for the person to comprehend and retain the information.

Explanation
H3PO4 is a weak acid because it only partially dissociates in water, releasing only a small number of hydrogen ions. It is classified as a weak acid due to its relatively low ionization constant. In contrast, HI, HBr, and HClO4 are strong acids, which completely dissociate in water, releasing a high concentration of hydrogen ions.

Explanation
The given net ionic equation correctly represents the reaction between acetic acid and potassium hydroxide. In this reaction, the acetic acid (CH3CO2H) reacts with the hydroxide ion (OH-) from potassium hydroxide to form acetate ion (CH3CO2-) and water (H2O). This reaction is a neutralization reaction, where the acidic hydrogen ion (H+) from acetic acid combines with the hydroxide ion to form water. The correct net ionic equation shows the formation of acetate ion and water as the products of the reaction.

Explanation
The molarity of a solution is calculated by dividing the moles of solute by the volume of the solution in liters. In this case, we need to convert the mass of MgCl2 to moles by dividing by its molar mass. The molar mass of MgCl2 is 95.211 g/mol. Therefore, the moles of MgCl2 is 2.891 g / 95.211 g/mol = 0.0304 mol. The volume of the solution is given as 500.0 mL, which is equivalent to 0.5000 L. Dividing the moles of MgCl2 by the volume of the solution gives us a molarity of 0.0304 mol / 0.5000 L = 0.0607 M or 6.073 × 10-2 M.

Explanation
In the given reaction, the species that undergoes reduction is H+. This is because reduction is the gain of electrons, and in the reaction, H+ gains two electrons to form H2 gas. The Sn species does not undergo reduction as it does not gain electrons, but rather loses two electrons to form Sn2+.

Explanation
To determine the volume of 0.300 M NaCl required to precipitate all the Pb2+ ions from the Pb(NO3)2 solution, we need to use the stoichiometry of the balanced equation. From the equation, we can see that 1 mole of Pb(NO3)2 reacts with 2 moles of NaCl to form 1 mole of PbCl2.

First, we need to calculate the number of moles of Pb(NO3)2 in the 25.0 mL solution using its molarity:

moles of Pb(NO3)2 = molarity × volume = 0.440 M × 0.0250 L = 0.0110 moles

Since the stoichiometry of the reaction is 1:2 for Pb(NO3)2 to NaCl, we need twice the number of moles of NaCl to precipitate all the Pb2+ ions.

moles of NaCl = 2 × moles of Pb(NO3)2 = 2 × 0.0110 moles = 0.0220 moles

Finally, we can calculate the volume of 0.300 M NaCl needed to have 0.0220 moles using its molarity:

volume of NaCl = moles / molarity = 0.0220 moles / 0.300 M = 0.0733 L = 73.3 mL

Therefore, the correct answer is 73.3 mL.