Compounds

Q. ntStandard free energies of formation at 298K are-237.2 , 394.4 and -8.2 for H20(l) , CO2(g) and pentane (g) .The value of E^° cell for pentane oxygen is?n

Q.

Difference between molecule and compound .With examples

Q.

Components of a compound can be separated by physical methods.

1. True

2. False

Q.

The formula of a compound having its constituent as $X$ and $Y$ is $X_2{Y}_3$. If the element will form its chloride then what will be the formula of the compound?

1. XCl₂

2. X₃Cl

3. XCl₃

4. X₂Cl

Q.

Arrange the following substances in the increasing order of intermolecular forces of attraction:
(a) Salt
(b) Water
(c) Carbon dioxide

Q.

Write symbols for the following radicals: chloride, oxide, sulphide, carbonate, sulphate and nitrate.

Q.

Which one of the following is a compound?

1. Carbon dioxide

2. Iron

3. Oxygen

4. Nitrogen

Q.

A/an ___________ is a simple substance which cannot be further divided into one or more pure components by any chemical means. Whereas, a/an ___________ is a chemical combination of two or more simple substances.

1. compound, element

2. mixture, compound

3. element, compound

4. mixture, element

Q. Which among the following is/are example(s) of pure substances?

1. Carbon dioxide and Nitrogen dioxide
2. Both A and B
3. Sugar solution and Chalk powder solution
4. Water and Ammonia

Q.

What is the difference between atom and molecule?

Q.

Iron and sulphur both are elements whereas iron sulphide is a compound, explain.

Q.

How compounds are classified?

Q.

Why is air called a mixture? Give five facts in support of your answer.

Q.

The intermolecular force and the intermolecular space are responsible for determining the mass of matter. (True/False)

Q.

The intermolecular space is maximum in

1. Gold

2. Stainless steel

3. Water

4. Hydrogen

Q. Which of the following is/are correct statement for compounds?

1. Compounds are pure and homogeneous mixtures.
2. Compounds are heterogeneous mixtures.
3. Compounds contain components that are loosely held together. They retain their individual properties.
4. Compounds consist of two or more substances combined in any ratio.

Q.

Classify the following substance as element, compound or mixture:

Chalk

Q. You are provided with a mixture of salt, sand, oil, and water. Write the steps involved for the separation of salt, sand, and oil from the mixture by giving an activity along with the diagram. ​

Q.

The force of attraction that exists between similar kinds of molecules is _______.

Q. A mixture of iron nails, salt, oil, and water is provided to you. Give stepwise methods to separate each component from this mixture?​

Q.

Write true or false for the following statement:

A chemical compound may occur either homogeneous or heterogeneous in nature.

1. True
2. False

Q.

What do we call the substance which is composed of two or more elements, and chemically combined in a fixed ratio by mass?

1. Homogeneous mixtures

2. Compound

3. Heterogeneous mixtures

4. Ions

Q.

Few properties are mentioned below. Specify the property as mixture or compounds:

STATEMENT 1: The constituents can be separated easily by physical means.

STATEMENT 2: Has a variable composition.

STATEMENT 3: The composition is always fixed.

STATEMENT 4: Shows entirely different properties from constituent elements.

1. statement 3 and 4 mixture and rest are compound.

2. statement 1 and 2 are mixtures and 3 and 4 are compounds.

3. 1 and 3 are compounds are rest are mixture.

4. statement 1 is mixture and rest are compound.

Q.

Identify the correct sequence of relevant steps to write the formula of cupric bisulphate.

1. Writing the symbol of a negative radical as ${\mathrm{HSO}}_4^{-2}$
2. Writing the symbol of a positive radical as ${\mathrm{Cu}}^{+2}$
3. Writing the symbol of a negative radical as ${\mathrm{HSO}}_4^{-}$
4. Writing the symbol of a positive radical as ${\mathrm{Cu}}^{+}$
5. Interchanging the valencies of positive and negative radicals and writing subscripts as 1 and 2.
6. Interchanging the valencies of positive and negative radicals and writing subscripts as 2 and 1.
7. Keeping HSO₄ in parenthesis
8. Keeping Cu in parenthesis

1. 2 1 5 8

2. 2 3 5 7

3. 4 3 6 8

4. 4 1 6 7

Q. Match the substances given in Column A with their uses given in Column B.
$\begin{array}{cccc}& A& & B\\ \left(i\right)& Gold& \left(a\right)& Thermometers\\ \left(ii\right)& Iron& \left(b\right)& Electricwire\\ \left(iii\right)& Aluminium& \left(c\right)& Wrappingfood\\ \left(iv\right)& Carbon& \left(d\right)& Jewellery\\ \left(v\right)& Copper& \left(e\right)& Machinery\\ \left(vi\right)& Mercury& \left(f\right)& Fuel\end{array}$

Q. A substance that is composed of two or more elements, chemically combined with one another in a fixed proportion of mass is called ___

Q.

A compound cannot be split into a simpler form.

1. True
2. False

Q.

Match the following:

$\begin{array}{cccc}\text{(i)}& \text{Can have variable composition of constituent elements}& \text{(A)}& \text{Compound}\\ \text{(ii)}& \underset{–}{}\underset{–}{}\underset{–}{}\text{is new substance formed due to reaction of two constituent elements}& \text{(B)}& \text{Mixture}\\ \text{(iii)}& \text{Constituent elements can be separated easily}& \text{(C)}& \text{Element}\\ \text{(iv)}& \text{Can be separated only by chemical or electrochemical reactions}& & \\ \text{(v)}& \text{Composition is always fixed}& & \\ \text{(vi)}& \text{Shows properties of constituent elements}& & \end{array}$

The correct pairs are:-

1. (ii, iv, v) – A, (iii, i) – B

2. (iv, v) – A, (iii) – B, (ii, i) - C

3. (iv, v) – A, (iii, i) – B, (ii) - C

4. (ii, iii, v) – A, (iv, i) – B

Q. Does aluminium require two more electron to complete its octet since it has three valence electrons and three more electrons are shared by three chlorine atoms? if not why

Q.

A formula of a compound having its constituents as X and Y is $X_2{Y}_3$. What can be the formula of the chloride if the element X forms one?

1. X₂Cl

2. XCl₂

3. X₃Cl

4. XCl₃