Ms. Watson's AP CHEM Ch. 4

2.

Which one of the following compounds is a weak electrolyte when dissolved in water?

Sodium hydroxide (NaOH)
Sodium acetate (NaCH3CO2)
Acetic acid (CH3CO2H)
Glucose (C6H12O6)

Correct Answer

A. Acetic acid (CH3CO2H)

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.

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3.

If 0.10 mole of each of the following compounds is dissolved to a volume of 1.0 L in water, which one will have the highest concentration of dissolved ions?

HF
NaOH
MgSO4
Al(NO3)3

Correct Answer

A. Al(NO3)3

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.

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4.

Which of the following compounds will be soluble in water: LiOH, Mg(OH)₂, Cu(OH)₂, and Fe(OH)₃?

LiOH only
LiOH and Mg(OH)2
Cu(OH)2 and Fe(OH)3
Mg(OH)2 and Cu(OH)2

Correct Answer

A. LiOH only

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.

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5.

Which of the following compounds will be soluble in water: KNO₃, Ca₃(PO₄)₂, CuCl₂, and Fe₂S₃?

KNO3 and Ca3(PO4)2
KNO3 and CuCl2
Ca3(PO4)2 and Fe2S3
CuCl2 and Fe2S3

Correct Answer

A. KNO3 and CuCl2

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.

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6.

A precipitate will form when aqueous AgNO₃ is added to an aqueous solution of ____.

KNO3
Cu(NO3)2
KI
Ca(ClO4)2

Correct Answer

A. KI

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.

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7.

A white solid is either NaI or NaNO₃. If an aqueous solution of the solid is prepared, the addition of which reagent will allow you to distinguish between the two compounds?

NaOH
HCl
K3PO4
Pb(NO3)2

Correct Answer

A. Pb(NO3)2

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.

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8.

How much do you like this chapter?

I love it
Its ok
I never love any chapter because I don't like chemistry
The bengals are not going to the super bowl so what does it matter

Correct Answer

A. I love it

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.

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9.

Which of the following compounds is a weak acid?

H3PO4
HI
HBr
HClO4

Correct Answer

A. H3PO4

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.

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10.

Write a net ionic equation for the reaction of aqueous acetic acid and aqueous potassium hydroxide.

CH3CO2H(aq) + KOH(aq) ® K+(aq) + CH3CO2-(aq) + H2O(l)
CH3CO2H(aq) + KOH(aq) ® KCH3CO2(aq) + H2O(l)
H+(aq) + OH-(aq) ® H2O(l)
CH3CO2H(aq) + OH-(aq) ® CH3CO2-(aq) + H2O(l)

Correct Answer

A. CH3CO2H(aq) + OH-(aq) ® CH3CO2-(aq) + H2O(l)

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.

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11.

If 2.891 g MgCl₂ is dissolved in enough water to make 500.0 mL of solution, what is the molarity of the magnesium chloride solution?

5.782 ´ 10-3 M
1.518 ´ 10-2 M
6.073 ´ 10-2 M
0.5505 M

Correct Answer

A. 6.073 ´ 10-2 M

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.

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12.

Which species in the reaction below undergoes reduction?Sn(s) + 2 H⁺(aq) ® Sn²⁺(aq) + H₂(g)

Sn
H+
Sn2+
H2

Correct Answer

A. H+

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+.

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13.

What volume of 0.300 M NaCl is required to precipitate all the Pb²⁺ ion from 25.0 mL of aqueous 0.440 M Pb(NO₃)₂?Pb(NO₃)₂(aq) + 2 NaCl(aq) ® PbCl₂(s) + 2 NaNO₃(aq)

73.3mL
42.1 mL
5.0mL
50.0mL

Correct Answer

A. 73.3mL

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.

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MS. Watson's AP Chem Ch. 4

Which one of the following compounds is a nonelectrolyte when dissolved in water

Quiz Preview

Which one of the following compounds is a weak electrolyte when dissolved in water?

If 0.10 mole of each of the following compounds is dissolved to a volume of 1.0 L in water, which one will have the highest concentration of dissolved ions?

Which of the following compounds will be soluble in water: LiOH, Mg(OH)₂, Cu(OH)₂, and Fe(OH)₃?

Which of the following compounds will be soluble in water: KNO₃, Ca₃(PO₄)₂, CuCl₂, and Fe₂S₃?

A precipitate will form when aqueous AgNO₃ is added to an aqueous solution of ____.

A white solid is either NaI or NaNO₃. If an aqueous solution of the solid is prepared, the addition of which reagent will allow you to distinguish between the two compounds?

How much do you like this chapter?

Which of the following compounds is a weak acid?

Write a net ionic equation for the reaction of aqueous acetic acid and aqueous potassium hydroxide.

If 2.891 g MgCl₂ is dissolved in enough water to make 500.0 mL of solution, what is the molarity of the magnesium chloride solution?

Which species in the reaction below undergoes reduction?Sn(s) + 2 H⁺(aq) ® Sn²⁺(aq) + H₂(g)

What volume of 0.300 M NaCl is required to precipitate all the Pb²⁺ ion from 25.0 mL of aqueous 0.440 M Pb(NO₃)₂?Pb(NO₃)₂(aq) + 2 NaCl(aq) ® PbCl₂(s) + 2 NaNO₃(aq)

MS. Watson's AP Chem Ch. 4

Which one of the following compounds is a nonelectrolyte when dissolved in water

Quiz Preview

Which one of the following compounds is a weak electrolyte when dissolved in water?

If 0.10 mole of each of the following compounds is dissolved to a volume of 1.0 L in water, which one will have the highest concentration of dissolved ions?

Which of the following compounds will be soluble in water: LiOH, Mg(OH)2, Cu(OH)2, and Fe(OH)3?

Which of the following compounds will be soluble in water: KNO3, Ca3(PO4)2, CuCl2, and Fe2S3?

A precipitate will form when aqueous AgNO3 is added to an aqueous solution of ____.

A white solid is either NaI or NaNO3. If an aqueous solution of the solid is prepared, the addition of which reagent will allow you to distinguish between the two compounds?

How much do you like this chapter?

Which of the following compounds is a weak acid?

Write a net ionic equation for the reaction of aqueous acetic acid and aqueous potassium hydroxide.

If 2.891 g MgCl2 is dissolved in enough water to make 500.0 mL of solution, what is the molarity of the magnesium chloride solution?

Which species in the reaction below undergoes reduction?Sn(s) + 2 H+(aq) ® Sn2+(aq) + H2(g)

What volume of 0.300 M NaCl is required to precipitate all the Pb2+ ion from 25.0 mL of aqueous 0.440 M Pb(NO3)2?Pb(NO3)2(aq) + 2 NaCl(aq) ® PbCl2(s) + 2 NaNO3(aq)

Which of the following compounds will be soluble in water: LiOH, Mg(OH)₂, Cu(OH)₂, and Fe(OH)₃?

Which of the following compounds will be soluble in water: KNO₃, Ca₃(PO₄)₂, CuCl₂, and Fe₂S₃?

A precipitate will form when aqueous AgNO₃ is added to an aqueous solution of ____.

A white solid is either NaI or NaNO₃. If an aqueous solution of the solid is prepared, the addition of which reagent will allow you to distinguish between the two compounds?

If 2.891 g MgCl₂ is dissolved in enough water to make 500.0 mL of solution, what is the molarity of the magnesium chloride solution?

Which species in the reaction below undergoes reduction?Sn(s) + 2 H⁺(aq) ® Sn²⁺(aq) + H₂(g)

What volume of 0.300 M NaCl is required to precipitate all the Pb²⁺ ion from 25.0 mL of aqueous 0.440 M Pb(NO₃)₂?Pb(NO₃)₂(aq) + 2 NaCl(aq) ® PbCl₂(s) + 2 NaNO₃(aq)