Compounds

Q.

H₂ is a compound.

1. True
2. False

Q.

Which of the following property does not describe a compound?

1. (a) It is composed of two or more elements

2. (b) It is a pure substance.

3. (c) It cannot be separated into constituents by physical means

4. (d) It is mixed in any proportion by mass.

Q.

What does a +2 charge mean?

Q. A compound will always retain all the properties of its constituent elements.

1. True
2. False

Q.

State the formula and valency of ammonium ion.

Q.

Match the following:

$\begin{array}{cccc}\left(i\right)& \text{Water}& \left(A\right)& \text{Compound}\\ \left(ii\right)& \text{Hydrogen}& \left(B\right)& \text{Element}\\ \left(iii\right)& \text{Salt}& & \\ \left(iv\right)& \text{Gold}& & \\ \left(v\right)& \text{Carbon dioxide}& & \\ \left(vi\right)& \text{Iron}& & \end{array}$
The correct pairs are:-

1. (i, iii, iv) – A, (ii, v, vi) - B

2. (i, iii, v) – A, (ii, iv, vi) - B

3. (i, ii, v) – A, (iii, iv, vi) - B

4. (i, ii, iii) – A, (iv, v, vi) - B

Q.

Two substances A and substance B when brought together forms a substance C with liberation of heat .the properties of C are entirely different from those of A and B. What is substance C ?
a) metal
B) element
C) compound
D) mixture

Q.

Give two examples of molecules containing two different kind of atoms.

Q.

Which of the following substances is an element?

1. Gold

2. Sugar

3. Water

4. Snow

Q.

The overall charge on sodium chloride formed by the combination of an anion (Cl^-) and a cation (Na⁺) is

1. + 2 charge

2. +1 charge

3. None of these.

4. -1 charge

Q.

Atoms of different kinds combine to form molecules of

1. an element

2. a compound

3. a mixture

4. all of the above

Q.

A ___ is formed by the physical combination of two or more substances, where the entities retain their identities.

1. Mixture

2. Element

3. Pure substance

4. Compound

Q. Which among the following statements are correct about water?

1. It is a compound.
2. It has two hydrogen atoms.
3. It has one oxygen atom.
4. It is an element.

Q.

Fill in the blanks:

A _____ shows the properties of constituent substances.

Q.

Which of the following is not a mixture?

1. Air

2. Milk

3. Blood

4. Water

Q.

A pure substance can be:

1. an element only

2. a compound only

3. either element or compound

4. any substance

Q.

Match the following:

$$\begin{array}{cccc}\left(\text{i}\right)& \text{Water}& \left(\text{A}\right)& \text{Compound}\\ \left(\text{ii}\right)& \text{Hydrogen}& \left(\text{B}\right)& \text{Element}\\ \left(\text{iii}\right)& \text{Salt}& & \\ \left(\text{iv}\right)& \text{Gold}& & \\ \left(\text{v}\right)& \text{Carbon dioxide}& & \\ \left(\text{vi}\right)& \text{Iron}& & \end{array}$$
The correct pairs are:-

1. (i, iii, iv) – A, (ii, v, vi) - B

2. (i, iii, v) – A, (ii, iv, vi) - B

3. (i, ii, v) – A, (iii, iv, vi) - B

4. (i, ii, iii) – A, (iv, v, vi) - B

Q.

Which of the following properties does not describe a compound?

1. It is composed of two or more elements

2. It is mixed in any proportion by mass

3. It has unique properties as compared to its constituents

4. It is a pure substance

Q.

Which one of the following can be considered as 'pure'?

1. Sugar

2. Aerosol

3. Soil

4. Soft drink

Q.

4. The properties of a compound are different from those of the ……………… that make it up.

Q.

Give the names of the elements present in:

aqueous solution of calcium chloride

Q.

The ratio of hydrogen and oxygen in water is ________.

Q.

Match the following:

$$\begin{array}{cccc}\text{(i)}& \text{Water}& \text{(A)}& \text{Compound}\\ \text{(ii)}& \text{Hydrogen}& \text{(B)}& \text{Element}\\ \text{(iii)}& \text{Salt}& & \\ \text{(iv)}& \text{Gold}& & \\ \text{(v)}& \text{Carbon}\text{dioxide}& & \\ \text{(vi)}& \text{Iron}& & \end{array}$$
The correct pairs are:-

1. (i, ii, iii) – A, (iv, v, vi) - B

2. (i, iii, iv) – A, (ii, v, vi) - B

3. (i, iii, v) – A, (ii, iv, vi) - B

4. (i, ii, v) – A, (iii, iv, vi) - B

Q.

State the valency of iodine ion.

Q.

The statement given below is incorrect. Write the correct statement.

A chemical compound has a variable composition.

Q.

Match the following:

$\begin{array}{cccc}\left(i\right)& \text{Water}& \left(A\right)& \text{Compound}\\ \left(ii\right)& \text{Hydrogen}& \left(B\right)& \text{Element}\\ \left(iii\right)& \text{Salt}& & \\ \left(iv\right)& \text{Gold}& & \\ \left(v\right)& \text{Carbon dioxide}& & \\ \left(vi\right)& \text{Iron}& & \end{array}$
The correct pairs are:-

1. (i, iii, iv) – A, (ii, v, vi) - B

2. (i, iii, v) – A, (ii, iv, vi) - B

3. (i, ii, v) – A, (iii, iv, vi) - B

4. (i, ii, iii) – A, (iv, v, vi) - B

Q. Elements in the compounds are present in ________ and cannot be separated by ______.

1. indefinite proportion, physical methods
2. definite proportion, physical methods
3. definite proportion, chemical methods
4. indefinite proportion, chemical methods

Q. Identify the correct pairs.

1. Gold - element, water - compound
2. Iron - compound, carbon dioxide - element
3. Carbon dioxide - compound, gold - compound
4. Iron - element, water - element

Q.

Pick out the odd one from amongst the following which does not belong to the set:

Hydrogen, steam, graphite, gold.

Q. A compound will always retain all the properties of its constituent elements.

1. True
2. False