Balancing of Chemical Equations

Q. Question 7.1
Write the balanced chemical equation for the following reaction:
Calcium hydroxide + Carbon dioxide $\to$ Calcium carbonate + Water

Q. Estimate the value $x$ to balance the given equation.

$M{g}_3{N}_2\left(aq\right)+x{H}_{2}O\left(l\right)\to 3Mg\left(OH{)}_2\right(aq)+2N{H}_3(g)$

1. 4
2. 6
3. 8
4. 2

Q.

Write the balanced chemical equations for the following reactions.
(A) Calcium hydroxide + Carbon dioxide → Calcium carbonate + water
(B) Zinc + Silver nitrate → Zinc nitrate + Silver
(C) Aluminium + copper chloride → Aluminium chloride + Copper
(D) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride.

Q.

How many atoms are present in the following? [5 MARKS]
1. $H_2{O}_2$
2. $H_{3}P{O}_4$
3. $C{O}_3^{2-}$
4. $C_{12}{H}_{22}{O}_{11}$
5. $H_{2}S{O}_4$

Q. State the number of atoms present in each of the following chemical species

(a) $C{O}_3^{2-}$

(b) $P{O}_4^{3-}$

(c) $P_2{O}_5$

(d) $CO$

Q. The total atoms of oxygen in ${\text{MnO}}_2$ is:

1. 2

Q. $H_2\left(g\right)+V_2{O}_5\left(s\right)\to V_2{O}_3\left(s\right)+H_{2}O\left(l\right)$
Let the coefficients for the given reaction be as follows:
$w{H}_2\left(g\right)+x{V}_2{O}_5\left(s\right)\to y{V}_2{O}_3\left(s\right)+z{H}_{2}O\left(l\right)$
What will be the values of w, x, y and z so that the reaction is balanced?

1. w = z, x = y, 5x = 3y + z
2. w = z, x = 2y, 5x = 3y + z
3. w = 2z, x = y, 5x = 3y + z
4. 2w = 2z, 2x = 2z, 2y = z

Q. is conserved in a chemical reaction.

1. Mass
2. Density
3. Volume

Q. What will be the values of the coefficients x, y and z if the given reaction is balanced?

${\text{xFeCl}}_3+\text{yMgO}\to {\text{Fe}}_{\text{2}}{\text{O}}_3+{\text{zMgCl}}_2$

1. x = 2, y = 3, z = 3
2. x = 2, y = 4, z = 3
3. x = 3, y = 2, z = 2
4. x = 3, y = 2, z = 3

Q. What will be $\text{A+B+C}$ if the following reaction is balanced?

${\text{AFeCl}}_3\text{(aq)}+\text{BMgO}\text{(s)}\to {\text{Fe}}_2{\text{O}}_3\text{(s)}+{\text{CMgCl}}_2\text{(aq)}$

1. 8
2. 9
3. 7
4. 10

Q. State the number of atoms present in each of the following chemical species

(a) $C{O}_3^{2-}$

(b) $P{O}_4^{3-}$

(c) $P_2{O}_5$

(d) $CO$

Q. The balanced chemical equation for potassium reacting with water is:

1. $\text{K}\text{(s)}+2{\text{H}}_2\text{O(l)}\to \text{KOH(aq)}+{\text{H}}_2\text{(g)}$
2. $2\text{K}\text{(s)}+{\text{H}}_2\text{O(l)}\to 2\text{KOH(aq)}+{\text{H}}_2\text{(g)}$
3. $\text{K}\text{(s)}+{\text{H}}_2\text{O}\text{(l)}\to \text{KOH(aq)}+{\text{H}}_2\text{(g)}$
4. $2\text{K}\text{(s)}+2{\text{H}}_2\text{O}\text{(l)}\to 2\text{KOH(aq)}+{\text{H}}_2\text{(g)}$

Q. Assertion (A): During a chemical reaction, the total mass of the reactants is equal to the total mass of the products.
Reason (R): During a reaction, the formation and destruction of atoms take place.

1. Both A and R are false
2. Both A and R are true but R is not the correct explanation of A
3. Both A and R are true and R is the correct explanation of A
4. A is true but R is false

Q. When a reaction takes place, the mass of the individual elements changes after the reaction is over.

1. False
2. True