Solutions - Conceptual

Ag⁺_(aq) + Cl^—_(aq) ⇄ AgCl_(s)

A student mixes dilute AgNO_3(aq) with excess NaCl_(aq) to form AgCl_(s), as represented by the net ionic equation above. Which of the diagrams below best represents the ions that are present in significant concentrations in the solution?

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Beaker X and beaker Y each contain 1.0 L of solution, as shown above. A student combines the solutions by pouring them into a larger, previously empty beaker Z and observes the formation of a white precipitate. Assuming that volumes are additive, which of the following sets of solutions could be represented by the diagram above?

Beaker X | Beaker Y| Beaker Z

• 2.0 M AgNO₃ | 2 0 M MgCl₂ | 4.0 M Mg(NO₃)₂ and AgCl_(s)

• 2.0 M AgNO₃ | 2 0 M MgCl₂ | 2.0 M Mg(NO₃)₂ and AgCl_(s)

• 2.0 M AgNO₃ | 1 0 M MgCl₂ | 1.0 M Mg(NO₃)₂ and AgCl_(s)

• 2.0 M AgNO₃ | 1 0 M MgCl₂ | 0.50 M Mg(NO₃)₂ and AgCl_(s)

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-5

Benzene, C₆H₆ , has the structure shown above. Considering the observation that benzene is only sparingly soluble in water, which of the following best describes the intermolecular forces of attraction between water and benzene?

• Benzene is nonpolar, therefore there are no forces between water and benzene.

• The H atoms in benzene form hydrogen bonds with the O atoms in water.

• Benzene is hydrophobic, therefore there is a net repulsion between water and benzene.

• There are dipole-induced dipole and London dispersion interactions between water and benzene.

A student uses visible spectrophotometry to determine the concentration of CoCl_2(aq) in a sample solution. First the student prepares a set of CoCl_2(aq) solutions of known concentration. Then the student uses a spectrophotometer to determine the absorbance of each of the standard solutions at a wavelength of 510nm and constructs a standard curve. Finally, the student determines the absorbance of the sample of unknown concentration.

The student made the standard curve above. Which of the following most likely caused the error in the point the student plotted at 0.050 M Co²⁺_(aq)?

• There was distilled water in the cuvette when the student put the standard solution in it.

• There were a few drops of the 0.100 M Co²⁺_(aq) standard solution in the cuvette when the student put the 0.050 M standard solution in it.

• The student used a cuvette with a longer path length than the cuvette used for the other standard solutions.

• The student did not run a blank between the 0.050 M Co²⁺_(aq) solution and the one before it.

Is the LEAST soluble in water

• CH₃CH₂CH₂CH₃

• CH₃CH₂CH₂OH

• CH₃COCH₃

• CH₃COOH

• CH₃CH₂CH₂NH₂

Tags

NGSS.HS-PS1-3

Equal volumes of 0.2 M solutions of lead(II) nitrate and potassium bromide are combined to form lead(II) bromide as a yellow precipitate. Which of the following is the correct net ionic equation for the reaction?

• Pb²⁺ _(aq) + 2 Br^- _(aq) --> PbBr_{2 (s)}

• K⁺ _(aq) + NO₃^- _(aq) --> KNO_{3 (aq)}

• Pb²⁺ _(aq) + 2 Br^- _(aq) + 2 K⁺ _(aq) + 2 NO₃^- _(aq) --> KNO_{3 (aq) +} PbBr_{2 (s)}

• Pb(NO₃)_{2 (aq)} + 2 KBr _(aq) --> PbBr_{2 (s)} + 2 KNO_{3 (aq)}

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

The reaction between aqueous strontium chloride (SrCl₂) and aqueous potassium sulfate (K₂SO₄) forms a precipitate of strontium sulfate (SrSO₄). Which of the following represents the net ionic equation for the reaction?

• Cl^- _(aq) + K⁺ _(aq) --> KCl _(aq)

• Sr²⁺ _(aq) + SO₄^2- _(aq) --> SrSO_{4 (s)}

• Sr²⁺ _(aq) + SO₄^2- _(aq) + 2 Cl^- _(aq) + 2 K⁺ _(aq) --> SrSO_{4 (s)} + 2 Cl^- _(aq) + 2 K⁺ _(aq)

• SrCl_{2 (aq)} + K₂SO_{4 (aq)} --> SrSO_{4 (s)} + 2 KCl _(aq)

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

The survival of aquatic organisms depends on the small amount of O₂ that dissolves in H₂O. The diagrams above represent possible models to explain this phenomenon. Which diagram provides the better particle representation for the solubility of O₂ in H₂O, and why?

• Diagram 1, because O₂ molecules can form hydrogen bonds with the H₂O molecules.

• Diagram 1, because O₂ and H₂O are polar molecules that can interact through dipole-dipole forces.

• Diagram 2, because the polar H₂O molecules can induce temporary dipoles on the electron clouds of O₂ molecules.

• Diagram 2, because the nonpolar O₂ molecules can induce temporary dipoles on the electron clouds of H₂O molecules.

Of the following organic compounds, which is LEAST soluble in water at 298 K?

• CH₃OH, methanol

• CH₃CH₂CH₂OH, l-propanol

• C₆H₁₂O₆, glucose

• C₆H₁₄, hexane

• CH₃COOH, ethanoic (acetic) acid

On the basis of molecular structure and bond polarity, which of the following compounds is most likely to have the greatest solubility in water?

• CH₄

• CCl₄

• NH₃

• PH₃