Tag: chemistry

Questions Related to chemistry

The concentration of matter in a material is:

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

  1. volume

  2. mass

  3. density

  4. none of these

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Correct Option: C
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.

Lustre is a property of:

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

  1. metals.

  2. non-metals.

  3. metalloids.

  4. none of the above.

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Correct Option: A
Explanation:

Lustre is a property of metals i.e. they have a shiny surface.

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

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

  1. $192\;g:cm^{-3}$

  2. $1.92\;g:cm^{-3}$

  3. $19.2\;g:cm^{-3}$

  4. $1920\;g:cm^{-3}$

Show answer
Correct Option: C
Explanation:
$1\;kg=1000\;g$
Conversion factor $ =\dfrac{1000\:gm}{1kg}$
$1\;m=100\;cm$
Conversion factor $ =\dfrac{1\:m}{100\:cm}$
$\therefore\;19200\;kg\:m^{-3}=19200\;kg\:m^{-3} \times\dfrac{1000\;g}{1\;kg}\times \begin{pmatrix}\dfrac{1\;m}{100\;cm}\end{pmatrix}^3$
$=19.200\;g/cm^3 = 19.2\:g\:cm^{-3}$

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.

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

  1. a, b

  2. b, c

  3. a, c

  4. All of the above

Show answer
Correct Option: D
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.

Identity the non-lustrous element.

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

  1. Bromine

  2. Iodine

  3. Silver

  4. Iron

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Correct Option: A
Explanation:

Iodine has lustrous appearance. Bromine is a non-metal so is non-lustrous. Silver and iron are metals and they are lustrous.

Formula of density is:

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

  1. $\dfrac{mass}{volume}$

  2. $\dfrac{volume}{mass}$

  3. $\dfrac{mass}{area}$

  4. $\dfrac{area}{mass}$

Show answer
Correct Option: A
Explanation:

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

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

Which of the following is used to galvanize metals, making them resistant to oxidation (rusting)?

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

  1. Zinc

  2. Iron

  3. Tin

  4. Aluminium

  5. Hydrogen

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Correct Option: A
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.

Beryllium, when combined with trace of chromium forms a gemstone called___________.

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

  1. Ruby

  2. Sapphire

  3. Emerald

  4. None of the above

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Correct Option: C
Explanation:

When combined with trace amounts of chromium, beryllium takes on a beautiful green hue as the gemstone commonly known as the emerald.

Aluminium foils are used for:

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

  1. wrapping chocolates and food stuff

  2. to prepare hydrogen

  3. both $A$ and $B$

  4. none of these

Show answer
Correct Option: C
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 $\text{C}$

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

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

  1. lithium

  2. potassium

  3. gold

  4. both A and B

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Correct Option: D
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.