Tag: chemical bonding and structure

Questions Related to chemical bonding and structure

The alloy bronze contains copper and tin. This is a:

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. homogeneous mixture

  2. heterogeneous mixture

  3. solid solution of two immiscible metals

  4. pure substance

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Correct Option: A
Explanation:

Bronze is an alloy consisting primarily of copper, commonly with about 12% tin and often with the addition of other metals (such as aluminium, manganese, nickel or zinc) and sometimes non-metals or metalloids such as arsenic, phosphorus or silicon.

All the alloys are homogeneous mixture.

Type metal is a well-known alloy made out of the three metals:

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. $Pb,\ Sb, \ Sn$

  2. $Ni,\ Cu,\ Ag$

  3. $Ag,\ Ni,\ Zn$

  4. $Al, \ Cu, \ Zn$

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Correct Option: A
Explanation:

Type metal is an alloy of lead, tin and antimony in different proportions depending on the application, be it individual character mechanical casting for hand setting, mechanical line casting or individual character mechanical typesetting and stereo plate casting.

Metallic bonding describes an array of positively charged metal cations surrounded by a sea of electrons that makes up a class of substances known as which of the following?

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. Alloys

  2. Allotropes

  3. Isomers

  4. Ions

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Correct Option: A
Explanation:

Answ: (A) Alloys

- We know that alloys is mixture of two or more metals. Which is held by metallic bond.
eg : brass which is made from copper and zinc.

An alloy is a specific type of substance that can best be described by which of the following?

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. An alloy is a mixture of various metals that can also contain non-metal elements.

  2. An alloy is a compound made of different types of metals.

  3. An alloy can only contain metals from the transition elements.

  4. An alloy can only contain two pure metals mixed in even quantities.

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Correct Option: A
Explanation:

Ans : (A) An alloy is a mixture of various metals that can also contain non-metals elements.

Eg : Steel is an alloy of iron (metal) and carbon (non-metal).

Statement 1: A mixture of pure metals is called an alloy. The melting point of an alloy will be lower than either of the component metals
Statement 2: The new bonds are weaker.

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1

  2. Both the Statement 1 and Statement 2 are correct, but Statement 2 is not the correct explanation of Statement 1.

  3. Statement 1 is correct, but Statement 2 is not correct.

  4. Statement 1 is not correct, but Statement 2 is correct.

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Correct Option: A
Explanation:

Both statement right and statement $2$ are correct Explanation.

Note : [alloy is the mixture of different metals .each metal having different size and structural arrangements. The different sizes of atoms in an alloy make their arrangement less regular than a pure metal. This makes the bonds between the atoms weaker and lower melting point.

Surface chemists design alloys for specific functions in everyday life.
Which of the following does not demonstrate a benefit of using an alloy?

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. Gold is mixed with copper or silver to make a less expensive form that can be used in jewelry.

  2. Smaller atoms of one metal are incorporated into the structure of larger metal atoms to reduce malleability and improve strength of the structure.

  3. Densities of metals are closely matched to increase desirable properties without increased cost.

  4. The conductivity has been eliminated due to the stronger bonding of the different types of metals.

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Correct Option: B
Explanation:

Ans: (B) Smaller atoms of one metal are incorporated into the structure of large metal atom to redue malleability and improve strength of structure.

Note : - Smaller atoms have greater ratios of surface area to volume which means greater ratio of atom boundary to dislocation.

Which substance would have the lowest melting point?

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. ${ Mg } _{ 3 }{ Al } _{ 2 }$

  2. $Ca{ Cl } _{ 2 }$

  3. ${ Cu } _{ 2 }Sn$

  4. ${ C } _{ 12 }{ H } _{ 22 }{ O } _{ 11 }$

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Correct Option: D
Explanation:

$C _{12}H _{22}O _{11} (Sucrose) -180^{\circ}C$

$Mg _{3}Al _{2}, CaCl _{2}$ and $Cu _{2}S _{n}$ show ionic bonding where as $C _{12}H _{22}O _{11}$ show covalent bonding. And we know melting point of covalent bonded compound is less then ionic compound.

Which of the following choices provides the BEST explanation for the fact that bronze, an alloy of copper and tin, is a good conductor of electricity?

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. Copper and tin have similar atomic radii.

  2. Copper and tin have similar melting points.

  3. The structure contains a "sea" of mobile valence electrons.

  4. The structure consists of strong covalent bonds between the atoms.

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Correct Option: C
Explanation:
Both tin and copper alloys having a free electron in their outermost valence shell. When potential energy is provided these electron move from one end to another and conduct the electricity.

An alloy of any metal with mercury is called amalgam and the electrical conductivity of an alloy is more than that of pure metals.

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. True

  2. False

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Correct Option: A
Explanation:

Alloys of mercury with metals like silver, copper, tin, zinc are used as amalgams.

Steel, composed of carbon and iron, is an example of an interstitial alloy.
Which of the following choices represents the best explanation for the fact that steel is harder and stronger than pure iron?

chemistry elements and compounds alloys and their properties metals, alloys and crystals chemical bonding and structure

  1. Carbon atoms are more reactive with oxygen than iron atoms. This prevents the steel from forming rust.

  2. Carbon atoms are smaller than iron atoms. Carbon atoms fill the spaces between iron atoms, making the structure more rigid.

  3. Carbon atoms form strong bonds with other carbon atoms. This forms a protective layer on the surface of steel.

  4. Both carbon and iron are good conductors of electricity. This makes steel harder and stronger than pure iron.

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Correct Option: B
Explanation:
Ans : (B) Carbon atoms are smaller than iron atoms. Carbon atoms fill the spaces between iron atom, making the structure $\%$ more rigid.
Note : - Steel is interstitial alloy of iron and carbon, due to smaller size of carbon, it easily fit between the metal atoms (iron) and provide Extra bonding to neighbouring atom, which makes alloy harder stronger (rigid).