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1- Brasses are alloys which normally contain copper with 5-40% zinc. Which one o

ID: 1712875 • Letter: 1

Question

1-

Brasses are alloys which normally contain copper with 5-40% zinc. Which one of the following does not happen as you increase the amount of zinc in brass?

Strength decreases

Density decreases

Elastic modulus decreases

Electrical conductivity decreases

Thermal conductivity decreases

Melting point decreases

2-

Silicon Carbide (SiC), a hard material that is most commonly used as an abrasive, has what type of bonding?

Van der Waals

Mostly ionic

Metallic

Covalent and Van der Waals

Mostly covalent

3-

Which of the following alloys contains the highest fraction of copper?

Naval brass

cartridge brass

gilding metal

muntz metal

5.nickel-silver

4-

which of the following is the correct order of increasing metal density?

Mg, Al, Ti, Zn, Cu, Pb, W

Mg, W, Al, Cu, Fe, Pb

W, Mg, Al, Zn, Ti, Cu, Pb

Mg, Al, Cu, Zn, Ti, W, Pb

Mg, Al, Cu, W, Ti, Pb, Fe

Zn, Mg, Ti, Al, Cu, W, Pb

Mg, Al, Ti, Cu, Zn, W, Pb

Ti, Mg, Al, Zn, Cu, Pb, W

Strength decreases

Density decreases

Elastic modulus decreases

Electrical conductivity decreases

Thermal conductivity decreases

Melting point decreases

2-

Silicon Carbide (SiC), a hard material that is most commonly used as an abrasive, has what type of bonding?

Van der Waals

Mostly ionic

Metallic

Covalent and Van der Waals

Mostly covalent

3-

Which of the following alloys contains the highest fraction of copper?

1.

Naval brass

2.

cartridge brass

3.

gilding metal

4.

muntz metal

5.nickel-silver

4-

which of the following is the correct order of increasing metal density?

Mg, Al, Ti, Zn, Cu, Pb, W

Mg, W, Al, Cu, Fe, Pb

W, Mg, Al, Zn, Ti, Cu, Pb

Mg, Al, Cu, Zn, Ti, W, Pb

Mg, Al, Cu, W, Ti, Pb, Fe

Zn, Mg, Ti, Al, Cu, W, Pb

Mg, Al, Ti, Cu, Zn, W, Pb

Ti, Mg, Al, Zn, Cu, Pb, W

Explanation / Answer

1. As we increase the percentage of zinc in brass following changes happen:

strength increases

density decreases

elastic modulus decreases

thermal and electrical conductivity increases

melting point decreases