Home / AP Chemistry: 2.4 Structure of Metals and Alloys – Exam Style questions with Answer- MCQ

AP Chemistry: 2.4 Structure of Metals and Alloys – Exam Style questions with Answer- MCQ

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Question

 
The figure presents a particulate diagram of a solid substance. Large, positively charged ions are arranged in a 3 by 3 array. Interspersed among the positively charged ions are small, negatively charged electrons.

Which of the following indicates whether the solid substance represented by the particulate diagram shown above conducts electricity and explains why or why not?

A  It conducts electricity because it is made of positive and negative particles.
 
B  It conducts electricity because electrons are free to move through the substance.
 
C  It does not conduct electricity because electrons are strongly attracted to specific positive particles.
 
D It does not conduct electricity because the positive particles are not free to move through the substance.
Answer/Explanation

Ans:B

 The diagram shows the structure of a metallic solid, which consists of a lattice of positive ions immersed in a sea of electrons in which electrons can move freely.

Question

Which of the following particulate-level diagrams best represents an interstitial alloy?

A  The figure presents a particulate-level diagram containing two types of particles: large white particles and small grey particles. The large white particles are arranged in a square lattice. The small grey particles are located throughout this lattice, at every other intersection of four large white particles.
 
B  The figure presents a particulate-level diagram containing two types of particles: white particles and grey particles of equal size. The particles are arranged in a diagonal lattice such that each particle is directly adjacent to four others: to the top left, to the top right, to the bottom left, and to the bottom right. About a quarter of the particles are grey. Each grey particle is adjacent only to white particles.
 
C  The figure presents a particulate-level diagram containing two types of particles: large negatively charged grey particles and small positively charged white particles. The two types of particles are arranged in a checkerboard pattern, such that each positively charged white particle is adjacent to four negatively charged grey particles, and that each negatively charged grey particle is adjacent to four positively charged white particles.
 
D  The figure presents a particulate level diagram containing grey particles arranged in a square lattice.
Answer/Explanation

Ans:A

In an interstitial alloy, atoms of one of the constituents are significantly smaller than the atoms of the other constituent and occupy the smaller spaces (interstices) among the larger atoms.

Question

 
 
The figure presents four rows of positively charged particles. The particles form columns. The top two rows are offset to the right of the bottom two rows so that the two rightmost columns in the top two rows do not have particles below them in the bottom two rows. Likewise, the two leftmost columns in the bottom two rows do not have particles above them in the top two rows. The positively charged particles are in a shaded region, labeled Electron Sea. Two arrows are drawn on the figure. The first arrow is on the left side of the top two rows and points rightward and the second arrow is on the right side of the bottom two rows and points leftward.

The diagram above best illustrates which of the following phenomena associated with solids that have metallic bonding?

A  Electrical conductivity, because it shows a lattice of positive ions immersed in a sea of electrons.
 
B Malleability, because it shows how adjacent layers of positive ions can move relative to one another while remaining in full contact with the electron sea.
 
C Heat conductivity, because it shows how layers of atoms can slide past one another, creating friction between layers and causing the temperature of the solid to increase.
 
D The ability to form substitutional alloys, because it shows how atoms of two different metals can combine in a one-to-one ratio.
Answer/Explanation

Ans: B

 The diagram shows the structure of a metallic solid, which has adjacent layers of positive ions sliding past one another (as indicated by the arrows) while staying within the shading of the electron sea.

Question27.

The table above provides some information about two types of steel, both of which are alloys of iron and carbon. Which of the following best helps to explain why high-carbon steel is more rigid than low-carbon steel?

(A) Elemental carbon is harder than elemental iron.

(B) The additional carbon atoms within the alloy make the high-carbon steel less dense.

(C) The additional carbon atoms within the alloy increase the thermal conductivity of the high-carbon steel.

(D) The additional carbon atoms within the alloy make it more difficult for the iron atoms to slide past one another.

 

Answer/Explanation

Ans:B

Question.

The table above provides some information about two types of steel, both of which are alloys of iron and carbon. Which of the following best helps to explain why high-carbon steel is more rigid than low-carbon steel?

(A) Elemental carbon is harder than elemental iron.

(B) The additional carbon atoms within the alloy make the high-carbon steel less dense.

(C) The additional carbon atoms within the alloy increase the thermal conductivity of the high-carbon steel.

(D) The additional carbon atoms within the alloy make it more difficult for the iron atoms to slide past one another.

Answer/Explanation

Ans:B

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