Combination Reaction

Q.

Calcium oxide reacts vigorously with water to produce slaked lime. $\mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{aq}\right)\to \mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)$ This reaction can be classified as:

1. Combination reaction.

2. Exothermic reaction.

3. Endothermic reaction

4. Oxidation reaction.

Q. $\text{C}+{\text{O}}_2\to {\text{CO}}_2+\text{Heat}$

The given reaction is a/an example of:

1. Combination reaction
2. Exothermic reaction
3. Endothermic reaction
4. Decomposition reaction

Q.

$\mathrm{CaO}+{\mathrm{H}}_2\mathrm{O}\to \mathrm{Ca}{\left(\mathrm{OH}\right)}_2$ is an example of………….?

Q.

C+O₂$\to$CO₂ The above reaction is a ____________ reaction.

1. combination

2. decomposition

3. displacement

4. double displacement

Q. Write your observations for the following chemical reaction and name the products formed?
(e) When ammonium chloride is heated with sodium hydroxide.

Q. Which of the following compound is obtained when quicklime reacts with water?

1. ${\text{Ca(HCO}}_3{)}_2$
2. ${\text{Ca(OH)}}_2$
3. ${\text{CaCO}}_3$
4. ${\text{Ca(NO}}_3{)}_2$

Q.

Can a combination reaction be an oxidation reaction?

Q.

Two different solid substances when mixed together and heated undergo a combination reaction. Write a relevant and balanced equation for the reaction.

Q.

In a combination reaction, the number of products are________

Q.

Which of the following are examples of combination reaction?

(i) $CaO+O_2\to 2CaC{O}_3$

(ii) $CaC{O}_3\to CaO+C{O}_2$

(iii) $MgO+C{O}_2\to MgC{O}_3$

(iv) $Fe+S\to FeS$

(v) $2AgCl+sunlight\to 2Ag+C{l}_2$

(vi) $C{H}_4+2O_2\to C{O}_2+2H_{2}O$

(vii) $N{a}_{2}O+H_{2}O\to 2NaOH$

1. (ii), (vii), (iv), (vi)

2. (i), (ii), (v), (vii)

3. (ii), (iii), (iv), (vi)

4. (i), (iii), (iv), (vii)

Q.

Which of these reactions involve two or more reactants combining to form a single product?

1. $2C_8{H}_{18}+25O_2\to$
   $16C{O}_2+18H_{2}O$

2. $8Fe+S_8\to 8FeS$

3. $MgO+C{O}_2\to MgC{O}_3$

4. $3Pb(N{O}_3{)}_2+2AlC{l}_3\to$
   $3PbC{l}_2+2Al(N{O}_3{)}_3$

Q.

The following reaction is a/an –
$C+O_2\to C{O}_2+Heat$

1. Combination reaction

2. Oxidation reaction

3. All of the above

4. Exothermic reaction

Q. Identify the general representation of a combination reaction.

1. $\text{A+B}\to \text{AB}$
2. $\text{A+B}\to \text{B+C}$
3. $\text{AB}\to \text{A+B}$
4. $\text{A+B+C}\to \text{X+Y}$

Q. Balance the following chemical equation and identify the type of chemical reaction?
$Mg\left(s\right)+C{l}_2\left(s\right)\to MgC{l}_2\left(s\right)$.

Q.

Which one of the following reactions involves the combination of two elements?

1. $CaO+C{O}_2\to CaC{O}_3$

2. $4Na+O_2\to 2N{a}_{2}O$

3. $S{O}_2+\frac{1}{2}{O}_2\to S{O}_3$

4. $N{H}_3+HCl\to N{H}_{4}Cl$

Q.

Which of the following is a combination reaction and which is a displacement reaction?

1. $C{l}_2+2KI\to 2KCl+I_2$
2. $2K+C{l}_2\to 2KCl$

Q.

___ is formed when CaO(quick lime) reacts with water.

1. 

2. Slaked Lime

3. 

4. Quick lime

Q. $Mg\left(s\right)+C{l}_2\left(g\right)\to MgC{l}_2\left(s\right)$

1. Decomposition reactions
2. Combination reaction
3. Displacement reaction
4. Double displacement reaction

Q. Vedika got very confused when she fund that as the candle burnt, it melted, became smaller and heat light and carbon dioxide was produced. A decomposition reaction also yields either two or more substances. Can you explain why they are different and why are they termed as chemical changes ?
[3 MARKS]

Q.

$2{\mathrm{SO}}_2+{\mathrm{O}}_2\to 2{\mathrm{SO}}_3+42\mathrm{KCal}.$

The above reaction is:

1. Endothermic reaction

2. Exothermic reaction

3. Combination reaction

4. Displacement reaction

Q.

A reaction in which a single product is formed from two or more reactants is known as __.

Q.

The reaction, $C+O_2\to C{O}_2+Heat$ is a/an

1. Combination reaction

2. Oxidation reaction

3. Exothermic reaction

4. All of the above

Q.

What is synthesis reaction ?

Q.

Match the following:

$\begin{array}{ccc}& \text{Reaction Names}& \text{Reactions}\\ i)& \text{Displacement Reaction}& A.)CaO+O_2\to 2Ca(OH{)}_2\\ ii)& \text{Decomposition Reaction}& B.)Fe+Pb(N{O}_3{)}_2\to Fe(N{O}_3{)}_2+Pb\\ iii)& \text{Redox Reaction}& C.)MgC{l}_2+Ca(OH{)}_2\to Mg(OH{)}_2+CaC{l}_2\\ iv)& \text{Combination Reaction}& D.)KCl{O}_3\to 2KCl+3O_2\\ v)& \text{Double Displacement Reaction}& E.)C{O}_2+H_2\to 2CO+H_{2}O\end{array}$

1. B, E, F, A and C

2. B, F, E, A and C

3. A, E, F, B and C

4. A, F, E, B and C

Q. Silicon burns brilliantly in the air and vigorously in oxygen to form silicon dioxide.

1. True
2. False

Q. Identify the combination reaction(s) among the following:

1. $2C_8{H}_{18}+25O_2\to 16C{O}_2+18H_{2}O$
2. $8Fe+S_8\to 8FeS$
3. $MgO+C{O}_2\to MgC{O}_3$
4. $3Pb(N{O}_3{)}_2+2AlC{l}_3\to 3PbC{l}_2+2Al(N{O}_3{)}_3$

Q.

Magnesium ribbon burns in air to produce white substance called magnesium oxide. Which type of reaction is this?

1. Exothermic reaction

2. Endothermic reaction

3. Oxidation reaction

4. Exothermic and oxidation reaction

Q.

Conversion of frost to water vapour is an example of

1. endothermic reaction

2. exothermic reaction

3. photochemical reaction

4. none of the above

Q.

A reaction in which a single product is formed from two or more reactants is known as __ reaction.

Q.

Give an example of a combination reaction that is exothermic.