AP Chemistry Unit 1 MCQ 1.5 minutes

Which of the following represents a pair of isotopes?

• 
• 
• 
• 

Tags

NGSS.HS-PS1-8

The elements I and Te have similar average atomic masses. A sample that was believed to be a mixture of I and Te was run through a mass spectrometer, resulting in the data above. All of the following statements are true. Which one would be the best basis for concluding that the sample was pure Te?

• Te forms ions with a −2 charge, whereas I forms ions with a −1 charge.

• Te is more abundant than I in the universe.

• I consists of only one naturally occurring isotope with 74 neutrons, whereas Te has more than one isotope.

• I has a higher first ionization energy than Te does

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following has the lowest first-ionization energy?

• Cs

• Pb

• Br

• Se

Tags

NGSS.HS-PS1-1

Which of the following has the highest electronegativity?

• Cs

• Pb

• Br

• Se

Tags

NGSS.HS-PS1-2

Which of the following has the largest atomic radius?

• Cs

• Pb

• Br

• Se

Tags

NGSS.HS-PS1-1

According to the information in the table above, a 1.00 g sample of which of the following contains the greatest mass of oxygen?

• Na₂O

• MgO

• K₂O

• CaO

Tags

NGSS.HS-PS1-7

The table above shows the first ionization energy and atomic radius of several elements. Which of the following best helps to explain the deviation of the first ionization energy of oxygen from the overall trend?

• The atomic radius of oxygen is greater than the atomic radius of fluorine.

• The atomic radius of oxygen is less than the atomic radius of nitrogen.

• There is repulsion between paired electrons in oxygen’s 2p orbitals.

• There is attraction between paired electrons in oxygen’s 2p orbitals.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following best helps to account for the fact that the Fion is smaller than the O2- ion?

• F^- has a larger nuclear mass than O^2- has.

• F^- has a larger nuclear charge than O^2- has.

• F^- has more electrons than O^2- has.

• F^- is more electronegative than O^2- is.

Tags

NGSS.HS-PS1-1

Two different ionic compounds each contain only copper and chlorine. Both compounds are powders, one white and one brown. An elemental analysis is performed on each powder. Which of the following questions about the compounds is most likely to be answered by the results of the analysis?

• What is the density of each pure compound?

• What is the formula unit of each compound?

• What is the chemical reactivity of each compound?

• Which of the two compounds is more soluble in water?

A student conducts an experiment to determine the percentage of silver in an alloy by first reacting the alloy with nitric acid. The student then precipitates the Ag⁺ (aq) by adding excess NaCl (aq) to form AgCl (s) according to the equation.

Ag⁺ (aq) + Cl^- (aq) --> AgCl (s) The precipitate is filtered, dried, and weighed.

Which of the following indicates the effect on the calculated percentage of silver if the precipitate was not dried completely before weighing it, and explains why?

• The calculated percentage is too low because the additional water will cause a significant quantity of the AgCl (s) to dissolve and wash through the filter paper.

• The calculated percentage is too low because water has a significantly lower molar mass than AgCl (s), which reduces the average mass of the precipitate.

• The calculated percentage is the same because the additional water does not affect the mass of the alloy, and the student will react the same mass of Ag regardless.

• The calculated percentage is too high because the additional water adds mass to the AgCl (s), and the student will calculate a higher mass of Ag in the sample.