Unit 3

The diagram above represents the photoelectric effect for a metal. When the metal surface is exposed to light with increasing frequency and energy of photons, electrons first begin to be ejected from the metal when the energy of the photons is $3.3 \times 10^{-19} \, \text{J}$. Which of the following is closest to the frequency of the light with photon energy of $3.3 \times 10^{-19} \, \text{J}$?

• 5.0 x 10^8 Hz

• 5.0 x 10^9 Hz

• 5.0 x 10^14 Hz

• 5.0 x 10^15 Hz

Tags

NGSS.HS-PS4-1

The diagram above represents the absorption spectrum for a pure molecular substance. Which of the following correctly indicates the type of transition observed for the substance in each of the regions of the absorption spectrum?

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Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-3

Based on their Lewis diagrams, which of the following pairs of liquids are most soluble in each other?

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Tags

NGSS.HS-PS1-1

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

In a paper chromatography experiment, a sample of a pigment is separated into two components, X and Y, as shown in the figure above. The surface of the paper is moderately polar. What can be concluded about X and Y based on the experimental results?

• X has a larger molar mass than Y does.

• Y has a larger molar mass than X does.

• X is more polar than Y.

• Y is more polar than X.

Tags

NGSS.HS-PS1-2

Which of the following questions about the components in a mixture could be investigated with a paper chromatography experiment?

• Do the components have different densities?

• Do the components have different molecular masses?

• Do the components have different molecular polarities?

• Do the components have different average molecular speeds?

An ionic crystal is added to water and starts to dissolve as shown in the particulate representation above. Based on the orientation of the water molecules, what can be assumed about the charge of the hydrated particle indicated by the arrow?

• The particle is positively charged, because the oxygen atoms in water are attracted to it.

• The particle is negatively charged, because hydrogen atoms in water are attracted to it.

• The particle is both positively and negatively charged, because the water molecules are attracted to it.

• The particle is neutral, because the dipoles of the water molecules neutralize the charge of the particle.

Tags

NGSS.HS-PS1-2

Solid Al(NO₃)₃ is added to distilled water to produce a solution in which the concentration of nitrate, [NO₃⁻], is 0.10 M. What is the concentration of aluminum ion, [Al³⁺], in this solution?

• 0.010 M

• 0.033 M

• 0.10 M

• 0.30 M

Tags

NGSS.HS-PS1-7

Of the three solutions listed in the table above, which one, if any, has the greatest electrical conductivity and why?

• 0.1 M HC2H3O2 (aq) because its molecules have the most atoms.

• 0.1 M KI (aq) because KI completely dissociates in water to produce ions.

• 0.1 M CH3OH (aq) because its molecules can form hydrogen bonds.

• All three solutions have the same electrical conductivity because the concentrations are the same.

Tags

NGSS.HS-PS2-5

A 2 L container will hold about 4 g of which of the following gases at 0°C and 1 atm?

• SO₂

• N₂

• CO₂

• NH₃