AP Chemistry : Solutions and States of Matter

Study concepts, example questions & explanations for AP Chemistry

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Example Questions

Example Question #1 : Representations Of Solutions

If 50g of NaCl are dissolved in 5 L of water what is the solute and what is the solvent?

Possible Answers:

NaCl can not be dissolved in water because NaCl is ionic and water is a polar solvent

They both are solvents because they dissolve into each other

Both are solutes since they are mixed together

NaCl is the solvent and H2O is the solute

NaCl is the solute and H2O is the solvent

Correct answer:

NaCl is the solute and H2O is the solvent

Explanation:

The solvent is what you the most off.  In this case water is the solvent and sodium chloride is the solute.

Example Question #1 : Representations Of Solutions

What would be the best solvent would you choose to dissolve C31H64?

Possible Answers:

Toluene (C7H8)

Acetone (C3H6O)

Ethanol (C2H5OH)

All of the above

Water

Correct answer:

Toluene (C7H8)

Explanation:

C31H64 is a non-polar substance and would dissolve best in a non-polar solvent like Toluene.

Example Question #2 : Representations Of Solutions

05

A student investigates a series of compounds in a thin layer chromatography experiment. The student has a sample of three organic compounds labeled A, B, and C as well as an unknown compound.  The student performs the experiment as shown on the left above and gets the results shown on the right.  What organic compound is in the unknown sample?

Possible Answers:

Sample B

Sample C

Sample A + B + C

None of the above

Sample A

Correct answer:

Sample C

Explanation:

The unknown sample gives a single spot that has migrated to the same amount as Sample C.

Example Question #1 : Spectroscopy And Electromagnetic Spectrum

What is the energy of a photon that has a wavelength of 540 nm?

Possible Answers:

None of the above

Correct answer:

Explanation:

 ; ;  

Example Question #631 : Ap Chemistry

What transition would emit the longest wavelength of light?

Possible Answers:

Not enough information given

n = 2 to n = 1

n = 4 to n = 1

n = 3 to n = 1

n = 4 to n = 3

Correct answer:

n = 4 to n = 3

Explanation:

Wavelength is inversely proportional to energy.  Since the transition from n=4 to n=3 is the lowest energy transition, it would have the longest wavelength.

Example Question #111 : Solutions And States Of Matter

What photon wavelength can promote a transition from the n = 1 (ground state) to the n = 3 (excited state)?

Possible Answers:

408 nm

306 nm

1 m

102 nm

204 nm

Correct answer:

102 nm

Explanation:

 

Example Question #65 : Solutions

A 3.0 eV light is shined on Gold ( Փ = 5.1 eV), silver (Փ =4.26 eV), Cesium (Փ = 2.1 eV), and Platinum (Փ = 6.35).  If Փ is the work function of the metal, what metal would have electrons ejected?

Possible Answers:

Cs

Pt

Au, Ag, and Pt

Au

Ag

Correct answer:

Cs

Explanation:

The work function is the energy required to remove an electron from a metal.  Only Cs metal has a work function less than the energy of the light.

Example Question #5 : Spectroscopy And Electromagnetic Spectrum

A student has a Blue #1 dye with a molar absorptivity of 1.30 x 105 M-1 cm-1 at 631 nm.  If the student runs this sample through a spectrophotometer and finds it has an absorption of 0.500 what is the dye’s molarity?  Assume a path length of 1.0 cm.

Possible Answers:

Correct answer:

Explanation:

Example Question #111 : Solutions And States Of Matter

In reality, the pressure of a gas is slightly less than the pressure predicted for an ideal gas. This is because __________.

Possible Answers:

the ideal pressure takes the volume of the molecules into consideration

repulsive interactions between gas molecules cause harder collisions with the vessel wall

the ideal pressure takes attractive intermolecular forces into consideration

intermolecular attractions slow the gas molecules before colliding with the vessel wall

Correct answer:

intermolecular attractions slow the gas molecules before colliding with the vessel wall

Explanation:

Ideal gas pressure only takes the repulsive forces between gas molecules into consideration. The truth is, gas molecules can also exhibit attractive forces with one another (London dispersion forces). This attractive force pulls the molecules inward and slows their velocity before striking the wall of the container. As a result, real gases exert slightly less pressure compared to the ideal pressure.

Example Question #2 : Solids, Liquids, And Gases

A gas is behaving ideally

2 mols of the gas would have what volume at STP?

Possible Answers:
0 L
need more information
22.4 L
44.8 L
11.2 L
Correct answer: 44.8 L
Explanation:

use PV = nRT

V = nRT / P  ; must covert T into K

V = (2)(0.0821)(273)/ 1

= 44.8 L

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