Tag: general introduction: importance and scope of chemistry

Questions Related to general introduction: importance and scope of chemistry

How many elements is expected in period number 10 of the periodic table?

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. 68

  2. 72

  3. 50

  4. 32

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Correct Option: B

Which of the following is an ionic compound?

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. ${ SO } _{ 3 }$

  2. $ICl$

  3. $KI$

  4. ${ CHCl } _{ 3 }$

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Correct Option: C
Explanation:
An ionic compound is composed of cation and anion and by the electrostatic force of attraction. But after formation, cation attracts the electron pair towards itself and cause some deformation of electron density of anion. Above all if the ionic character predominates over covalent character, then we call it ionic.

$KI$ consist of $K^+ $ cations  and $I^-$ anions.

The bond is purely ionic and the compound is ionic.


Option C is correct.

Which one is the man made element ?

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. Fe

  2. Ru

  3. Te

  4. none

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Correct Option: C

$0.14\ g$ of an element on combustion gives $0.28\ g$ of its oxide. That is that element?

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. Nitrogen

  2. Carbon

  3. Fluorine

  4. Sulphur

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Correct Option: D

Different states of matter are_________.

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. Gas

  2. Liquid

  3. Solid

  4. all of above

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Correct Option: D
Explanation:

Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space.
Three basic forms of matter are solid, liquid and gas.

Hence, option $D$ is correct.

Milk is a compound.

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. True

  2. False

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Correct Option: B
Explanation:

Milk is not compound. A compound is an entity consisting of two or more different atoms associating with chemical bonds. Milk is an emulsion or colloid of fat globules within a water-based fluid that contains dissolved carbohydrates and protein aggregates with minerals.

What will be the product, if dilute hydrochloric acid is added to $FeS$?

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. Element

  2. Mixture

  3. Compound

  4. None of these

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Correct Option: C
Explanation:

If you heat iron filings ans sulphur to a sufficiently high temperature you form iron sulphide 
$Fe + S \rightarrow FeS$
If you add HCl to this the following reaction occurs: 
$FeS + 2HCl \rightarrow FeCl _2 + H _2S$ 
$H _2S$ gas is given off and iron chloride is produced. 

Both are chemical compounds.

Which of the following is a compound?

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. $NaCl$

  2. $KCl$

  3. $NaOH$

  4. All of the above

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Correct Option: D
Explanation:

A compound is a chemical species that is formed when two or more atoms join together chemically, with covalent or ionic bonds.
Examples: $NaCl$, $KCl$ and $NaOH$

Brass is an element.

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. True

  2. False

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Correct Option: B
Explanation:

Brass is not an element but it is an alloy made of copper and zinc the proportions of zinc and copper can be varied to create a range of brasses with varying properties.

What is formed if a mixture of powdered iron and sulphur is heated in a test tube?

evs look, learn and experience matter: states, classification and properties study of matter general introduction: importance and scope of chemistry

  1. An element

  2. A mixture

  3. A compound

  4. None of the above

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Correct Option: C
Explanation:

A mixture is made when you combine matter in a way where the components can be separated again. A compound results from a chemical reaction between components, forming a new substance. For example, you can combine iron filings with sulfur to form a mixture. All it takes is a magnet to separate the iron from the sulfur. On the other hand, if you heat the iron and sulfur, you form iron sulfide, which is a compound.
$Fe+S \rightarrow FeS$