Tag: chemistry

Questions Related to chemistry

The material mixed before ore is subjected for smelting in the extraction of iron are:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. cake and silica

  2. coke and limestone

  3. limestone and silica

  4. coke, limestone and silika

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Correct Option: B
Explanation:

Smelting is a form of extraction metallurgy. Its main purpose is to get pure metal from th ore. Coke and limestone are added. Coke acts as an reducing agent and limestone acts as a flux. Concentrated ore of iron i.e. haemetite is used.

Which of the following non-metal is a good conductor of electricity?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Graphite

  2. Hydrogen

  3. Phosphorous

  4. Bromine

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Correct Option: A
Explanation:

Graphite is a non-metal. Generally, non-metals are bad conductors of electricity but graphite is an exception. Because the structure of graphite is in such a way that electrons can move freely and conduct electricity. Due to this property, it is used in making of pencil cells. 


Hence, the correct option is $A$

Heamatite ore is concentrated by:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. gravity separation method

  2. forth floatation

  3. amalgamation

  4. hand picking

Show answer
Correct Option: A
Explanation:

Heamatite is an iron oxide with a chemical composition of $Fe _2O _3$. Gravity Separation or Hydraulic Washing (Levigation)

Heamatite ore is concentrated by gravity separation method. This method of concentration of the ore is based on the difference in specific gravities of the metallic ore and gangue particles. Generally metal ores are heavier than the gangue associated with them.
By flowing the powdered ore in a current of water, the lighter rocky impurities can be washed away and the ore particles are left behind. For this, either wilfley table or Hydraulic classifier is used. Generally oxide and carbonate ores are concentrated by this method. i.e. haematite and cerussite.

Which non-metallic element is in liquid form?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Carbon

  2. Hydrogen

  3. Bromine

  4. Phosphorous

Show answer
Correct Option: C
Explanation:

Bromine is a halogen and a non metal. It is a red brown liquid at room temperature. Its atomic number is 35. It belongs to fourth period and $VII :A$ group of the periodic table. 

Carbon and phosphorus are solids and hydrogen is a gas.

In general, the number of electrons in the outermost shell of a metal atom is:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. 1

  2. 1-3

  3. 1-8

  4. 8

Show answer
Correct Option: B
Explanation:

Metals have 1-3 electrons in their outermost orbit. They are present on the extreme left of the periodic table. They tend to donate electrons and obtain the stable electronic configuration of the nearest noble gas. The valency on metals also ranges from 1-3.


Hence, the correct option is $B$

Which metal is found in liquid state at room temperature?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Iron

  2. Zinc

  3. Mercury

  4. Aluminium

Show answer
Correct Option: C
Explanation:

Generally all the metals are found in the solid state at room temperature. The exception to this is mercury. Mercury is found in liquid state at room temperature. Whereas non metals are found in the 3 states at room temperature $i.e.$ solid, liquid and gas.

The metal reacting readily with cold water is:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. gold

  2. mercury

  3. sodium

  4. magnesium

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Correct Option: C

 Which of the following is the best electrical conductor?

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. Gold

  2. Silver

  3. Copper

  4. Aluminium

Show answer
Correct Option: B
Explanation:

The most electrically conductive element is silver, followed by copper and gold. Silver also has the highest thermal conductivity of any element and the highest light reflectance.  Because silver tarnishes, it is less desirable for high frequencies because the exterior surface is less conductive.
As to why silver is the best conductor, the answer is that its electrons are freer to move than those of the other elements. This has to do with its valence and crystal structure.

The most abundant metal in earth's crust is: 

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. iron

  2. magnesium

  3. calcium

  4. aluminium

Show answer
Correct Option: D
Explanation:

Aluminium is the most abundant metal in earth's crust with $\text{percentage by weight = 8.23%}$ followed by iron with $\text{5.63% by weight }$.

Hence, answer is option $D$.

The most abundant element in earth's crust is:

chemistry non-metals introduction to non-metals occurence of metals occurrence of metals and non metals

  1. hydrogen

  2. oxygen

  3. nitrogen

  4. silicon

Show answer
Correct Option: B
Explanation:

The most abundant element in earth's crust is oxygen with$\text{ Percent by weight = 46.1% followed by aluminium with 8.23% by weight.}$
Hence, the answer is option $B$.