Chemical Reaction

Q.

What is a displacement reaction? Give an example.

Q.

Name the chemical reaction. $\mathrm{Fe}+{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)\to {\mathrm{FeSO}}_4\left(\mathrm{aq}\right)+\mathrm{Cu}\left(\mathrm{s}\right)$

Q. Why is electrolysis of water a chemical change?

Q.

When wax is burnt (in the form of a wax candle), then water and carbon dioxide are formed.This shows the "change in state" characteristic of reactions.

1. True

2. False

Q.

(a) What is a chemical reaction ?

(b) State the conditions necessary for a chemical change or reaction.

Q.

What does $2H_{2}O$ represent?

1. 2 molecules of water

2. 6 atoms in total

3. 6 atoms in total or 2 molecules of water

4. 4 atoms in total or 2 molecules of water

Q.

$\text{CaO(s)}+{\text{H}}_2\text{O (l)}\to {\text{Ca(OH)}}_2\text{(aq)}+\text{Heat}$

What can be inferred from the above reaction?

1. Calcium oxide ($\text{CaO}$) is solid.
2. Water (${\text{H}}_2\text{O})$ is in vapour state.
3. Calcium hydroxide [${\text{Ca(OH)}}_2$] is aqueous in nature.
4. The given reaction is exothermic in nature.

Q.

Iron nails were dipped in a solution kept in a test tube. After half an hour, it was observed that the colour of the solution has changed. The solution present in the test tube was that of

1. Zinc sulphate

2. Copper sulphate

3. Iron sulphate

4. Aluminium sulphate

Q. Name the type of the following chemical reaction.

1. Combination
2. Decomposition
3. Double displacement
4. Synthesis

Q. In a reaction, represents that the reactant or the product is present as a solution with water as a solvent.

1. (s)
2. (g)
3. (aq)
4. (liq)

Q.

Classify the following changes as physical and chemical change

d) Blackening of silverware

Q.

Law of conservation of mass states that ______ can neither be created nor destroyed.

Q.

Question 3

Define combination reaction. Give an example of a combination reaction that is also exothermic.

Q.

Is it possible to liquefy CO₂ gas at 50⁰C? Give a reason.

Q.

Give an example to show that constituents of a mixture always retain their physical and chemical properties.

Q.

Which law of chemical combination is referred to as the ‘law of indestructibility of matter’

Q.

What do you understand by 'chemical reaction' ?

Q. Question 2
${\text{Fe}}_2{\text{O}}_3+2\text{Al}\to {\text{Al}}_2{\text{O}}_3+2\text{Fe}$
The above reaction is an example of a:

Q.

Analyze the diagram below:

The rate of the reaction in a test tube B is greater than the rate of the reaction in a test tube A. Which of the following factor could probably be the main reason for this?

1. The pressure on the reactants
2. The temperature of the reactants
3. The presence of light
4. The concentration of the reactants.

Q. Atomicity is defined as the total number of atoms present in a molecule.

1. True
2. False

Q.

F) Pick the odd one out . Give reason for your choice

(a) Boiling an egg , Preparing idli , writing a book , baking bread

Q. Which among the following is an example of gas in gas solution?

1. Air
2. Soda pop
3. Gasoline
4. Alloys

Q. In metal reactivity series hydrogen is present at ______________.

1. top
2. bottom
3. it is not present in metal reactivity series
4. middle

Q.

The reaction between Iron and Copper sulphate is a displacement reaction.

1. True
2. False

Q. Which of these does not influence the rate of reaction?

1. Nature of the reactants
2. Concentration of the reactants
3. Temperature of the reactions
4. Molecularity of the reaction

Q. Define
A)Atom
B)Elements
C)Compound

Q. Identify the type of reaction in the following example.

Q. Define
A)Atom
B)Elements
C)Compound

Q.

Name the oxide of sulphur which reacts with water to give sulphuric acid.

1. $S{O}_2$

2. $S{O}_3$

3. SO

4. $S_{2}O$

Q.

Calculate the number of atoms in $52$ a.m.u. of $\mathrm{He}$.