Tag: general characteristics and uses of metals

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Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Four metals $P$, $Q$, $R$ and $S$ react with water as given below:
I. $P$ reacts with cold water
II. $Q$ reacts with hot water
III. $R$ reacts with steam
IV. Red hot $S$ reacts with steam.
Then, highly reactive metal is:

  1. $P$
  2. $Q$
  3. $R$
  4. $S$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The highly reactive metal is $P$ as it reacts with cold water. This is because, the reaction with cold water requires lowest energy of activation.

Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Select the object from the following which can shine (have lusture) _____________

  1. glass bowl and wooden bowls

  2. towel and toys

  3. shirts and scarfs

  4. ornaments and brass utensils
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

1) ornaments and brass utensils both are made up of metals.

2) Metals are lustrous because of the free electrons they have.

3) The free electrons can move freely in the metal causing any light incident on them to get reflected back.

4) This reflection is specular reflection rather than diffused and thus the metal surface appears shiny or lustrous.

Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Metallic radii of some transition elements are given below. Which of these elements will have the highest density?
Element                    $Fe$     $CO$       $Ni$     $Cu$ 
Metallic radii/pm     126     125     125    128

  1. same

  2. $Ni$
  3. $Co$
  4. $Cu$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Density is mass divided by volume. For transition elements in the same period, as atomic number increases, the atomic radius generally decreases or stays similar, while the atomic mass increases significantly. Copper (Cu) has the highest atomic mass among the listed elements (Fe, Co, Ni, Cu), leading to the highest density.

Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Which one of the following four metals would be displaced from the solution of its salt by other three metals?

  1. Mg

  2. Ag

  3. Zn

  4. Cu
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ag metal would be displaced from the solution of its salt by Mg, Zn or Cu metals.

Among the given metals, the standard reduction potential for the half reaction $\displaystyle Ag^+ + e^- \rightarrow Ag$ is maximum.

Hence, among the given metals (ions),  $\displaystyle Ag^+ $ ion has maximum strength as oxidising agent. Hence, $\displaystyle Ag^+$ ion gains an electron and other metals loses electron.

Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Read the following statements and answer as true or false.
The presence of carbon in pig iron makes it brittle.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 Pig iron has a very high carbon content, typically 3.8–4.7%, along with silica and other constituents of dross, which makes it very brittle, and not useful directly as a material except for limited applications.

Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Which of the following is not correct observation based on Ellingham diagram?

  1. A metal can reduce the oxide of other metal which lies above it in Ellingham diagram
  2. $CO$ is more effective than $C$ as reducing agent below $170^{o}C$
  3. $\Delta G^{o}$ metal oxide is higher than of $CO _{2}$ hence oxidation of metal sulphides to oxides is not favourable

  4. Need for conversion of metal sulphide to metal oxide before reduction can be explained thermodynamically
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

As moving down of bottom of diagram metals becomes more reactive oxides will be hard to reduce.A given metal can reduce the oxides of other metal which lies above it in Ellingham diagram.

Multiple choice chemistry materials: metals and non-metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Generally ornaments are usually made up of 24 karat gold.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ornaments and jewellry can't be made of 100 per cent pure gold or 24 Karat gold as it is very soft and delicate. Most of jewellry are made of 22 karat to 10 karat of gold.


24 carat is pure gold so it has less strength to make ornaments. To impart strength, some impurities are mixed such as copper to make the 22 carat gold which is suitable for making ornaments. Therefore, 24 carat gold is pure gold , it is weak to make ornaments.

Multiple choice chemistry materials: metals and non-metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Non-metals have many different colours.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Non-metals like phosphorous exist in various colors such as white, scarlet, yellow, red, violet, black. Similarly, sulfur is pale yellow, bromine is red-brown colored in liquid and vapor state.
Thus option $A$ is correct.

Multiple choice chemistry materials: metals and non-metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Non-metals are less dense and have low melting and boiling points as compared to metals.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The melting point of an element is the temperature at which it converts from solid form to a liquid. In metals, there are two types of bonding that lead to higher melting points: covalent and metallic. Covalent bonds are when electron pairs are shared equally between atoms, and they pull atoms even closer together if multiple pairs of electrons are involved. Metallic bonds involve electrons that are delocalized: they float between many atoms, not just two, and positively charged nuclei are firmly bound to the surrounding "sea" of electrons. As strong bonds between atoms give elements higher melting points, it is also true that lower melting points are a result of weaker bonds or a lack of bonds between atoms. Therefore non-metals lack metallic bonding between atoms therefore have lower melting and boiling point than metals.
Also the closed and dense packing of metals in the lattice impart them high density and strength that lacks in non-metals.
Thus option A is true.

Multiple choice chemistry materials: metals and non-metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

Metals are lustrous.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Metals are lustrous because of the free electrons present in them. The free electrons can move freely in the metal causing any light incident on them to get reflected back. This reflection is specular reflection rather than diffused and thus the metal surface appears shiny or lustrous.
Hence, option $A$ is correct.