AP Chemistry : Solutions and States of Matter
Study concepts, example questions & explanations for AP Chemistry
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Example Questions
Example Question #3 : Representations Of Solutions
If 50g of NaCl are dissolved in 5 L of water what is the solute and what is the solvent?
NaCl can not be dissolved in water because NaCl is ionic and water is a polar solvent
NaCl is the solvent and H2O is the solute
Both are solutes since they are mixed together
They both are solvents because they dissolve into each other
NaCl is the solute and H2O is the solvent
NaCl is the solute and H2O is the solvent
The solvent is what you the most off. In this case water is the solvent and sodium chloride is the solute.
Example Question #4 : Representations Of Solutions
What would be the best solvent would you choose to dissolve C31H64?
Water
Toluene (C7H8)
All of the above
Acetone (C3H6O)
Ethanol (C2H5OH)
Toluene (C7H8)
C31H64 is a non-polar substance and would dissolve best in a non-polar solvent like Toluene.
Example Question #5 : Representations Of Solutions
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?
Sample C
None of the above
Sample A + B + C
Sample B
Sample A
Sample C
The unknown sample gives a single spot that has migrated to the same amount as Sample C.
Example Question #631 : Ap Chemistry
What is the energy of a photon that has a wavelength of 540 nm?
None of the above
Example Question #632 : Ap Chemistry
What transition would emit the longest wavelength of light?
Not enough information given
n = 4 to n = 3
n = 4 to n = 1
n = 3 to n = 1
n = 2 to n = 1
n = 4 to n = 3
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 #632 : Ap Chemistry
What photon wavelength can promote a transition from the n = 1 (ground state) to the n = 3 (excited state)?
102 nm
306 nm
204 nm
408 nm
1 m
102 nm
Example Question #3 : Spectroscopy And Electromagnetic Spectrum
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?
Au, Ag, and Pt
Au
Ag
Cs
Pt
Cs
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 #635 : Ap Chemistry
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.
Example Question #1 : Solids, Liquids, And Gases
In reality, the pressure of a gas is slightly less than the pressure predicted for an ideal gas. This is because __________.
the ideal pressure takes the volume of the molecules into consideration
the ideal pressure takes attractive intermolecular forces into consideration
repulsive interactions between gas molecules cause harder collisions with the vessel wall
intermolecular attractions slow the gas molecules before colliding with the vessel wall
intermolecular attractions slow the gas molecules before colliding with the vessel wall
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?
use PV = nRT
V = nRT / P ; must covert T into K
V = (2)(0.0821)(273)/ 1
= 44.8 L
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