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

Why are metals lustrous?

  1. Light is transmitted through delocalized electrons

  2. They have a high boiling point

  3. Light is reflected through delocalized electrons

  4. Light does not travel through metals at all
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A metal is a lattice of metal "ions" in a "sea" of delocalised electrons - mobile electrons. Photons of light do not penetrate very far into the surface of a metal and are typically reflected, or bounced off, the metallic surface, by the mobile electrons and what you get is metallic reflection, which is lustrous.

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 example possess lustre?

  1. Silver

  2. Platinum

  3. Mercury

  4. All of above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$A,\ B$ and $C$ are all metals with free electrons. Photons of light do not penetrate very far into the surface of a metal and are typically reflected or bounced off the metallic surface by the mobile electrons and what you get is a metallic reflection, which is lustrous.

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

Why iron is used widely in construction of buildings, bridges, railway lines etc?

  1. Iron is a good conductor of electricity

  2. Iron is ductile

  3. Iron have high tensile strength

  4. Iron is malleable
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Metals (except sodium, potassium) have very high tensile strength.
For example - iron can bear a lot of tensile strength. So, it is used in construction of buildings, bridges, railway lines etc.

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

The density of ice is $0.921\;g\ cm^{-3}$. Calculate the mass of a cubic block of ice which is $76\;mm$ on each side.

  1. $49 \:g$
  2. $4\times 10^2\;g$
  3. $0.04 \:g$
  4. $4\times 10^3\;g$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Now, 1 $mm $ =   0.1 $cm$

$ \therefore $ 76$mm $ =   7.6 $cm$
Volume of cube $ =  $ $ (7.6)^3$ $ =  $ 438. 98 $ cm^3$
Now, mass $ =  $ density $ \times $ volume $ =  $ 0.921 $ \times $ 438.98 $ =  $ 404 $g$ $ =  $ $ 4.04 \times10^2 :g$

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

The mass of a piece of paper is $0.02\;g$ and the mass of a social substance and the piece of paper is $20.036\;g$. The volume of the solid substance is $2.16\;cm^3$. Calculate the density of the substance.

  1. $9.98$
  2. $7.36$
  3. $7.14$
  4. $9.268$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Mass of piece of paper $=0.02\;g$


Mass of solid substance and piece of paper $=20.036\;g$

$\therefore$ Mass of solid substance $=20.036\;g-0.02\;g$

$\approx 20.02\;g$

Volume of solid $=2.16\;cm^3$

Density = $\dfrac{Mass}{Volume}=\dfrac{20.02}{2.16}=9.268 \ g/cm^3$

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

The mass of steel sphere having density 7850$\;kg :m^{-3}$ and radius 0.15$\;m$ is:

  1. 112$\;kg$.
  2. 290$\;kg$.
  3. 110.9$\;kg$.
  4. 300$\;kg$.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mass  of the sphere, $M = Density \times Volume$


Volume of the sphere is, $ V= \dfrac {4}{3} \pi r^3$


$ V=  \dfrac {4}{3} \pi (0.15)^3= 0.01412  \ m^{3} $

$M= 7850 \times 0.01412$

$= 110.9 \:kg$