Tag: chemistry

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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

The concentration of matter in a material is:

  1. volume

  2. mass

  3. density

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For a pure chemical, the mass concentration is equal to its density (mass divided by volume); thus the mass concentration of a component in a mixture can be called density of a component in a mixture.

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

Convert $19200\;kg/m^3$ into $g:cm^{-3}$.

  1. $192\;g\:cm^{-3}$
  2. $1.92\;g\:cm^{-3}$
  3. $19.2\;g\:cm^{-3}$
  4. $1920\;g\:cm^{-3}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
$1\;kg=1000\;g$
Conversion factor $ =\dfrac{1000\:gm}{1kg}$
$1\;m=100\;cm$
Conversion factor $ =\dfrac{1\:m}{100\:cm}$
$\therefore\;19200\;kg\:m^{-3}=19200\;kg\:m^{-3} \times\dfrac{1000\;g}{1\;kg}\times \begin{pmatrix}\dfrac{1\;m}{100\;cm}\end{pmatrix}^3$
$=19.200\;g/cm^3 = 19.2\:g\:cm^{-3}$

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

Mark the correct statement.
a) Metals lose their lustre on keeping in air.
b) Gold is lustrous.
c) Metals are lustrous and can be polished.

  1. a, b

  2. b, c

  3. a, c

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

Metals lose their lustre when kept exposed to air for long time and gets a dull appearance. It loses most of its shine and lustre.

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

Formula of density is:

  1. $\dfrac{mass}{volume}$
  2. $\dfrac{volume}{mass}$
  3. $\dfrac{mass}{area}$
  4. $\dfrac{area}{mass}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Density, of a substance is define as mass per unit volume. Density $(\delta)$ is equal to mass $(m)$ divided by volume $(V)$. 

$Density = \dfrac{mass}{volume}$

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 used to galvanize metals, making them resistant to oxidation (rusting)?

  1. Zinc

  2. Iron

  3. Tin

  4. Aluminium

  5. Hydrogen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Zinc is used to galvanize metals, making them resistant to oxidation (rusting). Zinc is stronger reducing agent than the metal to be galvanized (such as iron) and hence, zinc can be more easily oxidised. Thus, during corrosion, zinc is oxidised. This prevents corrosion (rusting) of other metal.

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

Aluminium foils are used for:

  1. wrapping chocolates and food stuff

  2. to prepare hydrogen
  3. both $A$ and $B$

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Aluminium foils are impermeable to oxygen and water; thus are used for wrapping chocolates and foodstuff. 


It can be used for the preparation of hydrogen using the reaction of aluminium foil with a sodium hydroxide solution.


$2Al + 2NaOH + 6H _2O \rightarrow  2Na[Al(OH) _4] + 3H _2\uparrow$


Hence, the correct option is $\text{C}$

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

Soft metals which can be cut with a knife is/are :

  1. lithium

  2. potassium

  3. gold

  4. both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Metals like lithium, sodium and potassium can be cut with a knife because their melting point is low as compared to other alkali metals. 


Although alkaline earth metals with the exception of magnesium and beryllium can be also cut with a knife.

Hence the correct option is D.