chemistry class 9 , icse board, pls help me in finding answers
Answers
Answer:
to balance this equation take help of balancing machine
Explanation:
Answer:
(a) MnO₂ + 4 HCl ⇒ MnCl₂ + 2 H₂O + Cl₂
(b) P + 5 HNO₃ ⇒ 5 NO₂ + H₂O + H₃PO₄
(c) Mg₃N₂ + 6 H₂O ⇒ 3 Mg(OH)₂ + 2 NH₃
(d) 4 NH₃ + 3 O₂ ⇒ 2 N₂ + 6 H₂O
(e) 2 Al(OH)₃ ⇒ Al₂O₃ + 3 H₂O
(f) 4 HNO₃ ⇒ 2 H₂O + 4 NO₂ + O₂
(g) Ca(OH)₂ + 2 NH₄Cl ⇒ CaCl₂ + 2 H₂O + 2 NH₃
Explanation:
To balance a chemical equation, see that the number of atoms of each element on both sides of the equation is the same, i.e., LHS(Left-hand side) and RHS(Right-hand side).
There are two ways to balance chemical equations. One way is to directly write the numbers in the equation and the other is to show steps as to how you got the solution.
(a) MnO₂ + HCl ⇒ MnCl₂ + H₂O + Cl₂
To balance:
The number of Mn atoms is the same on both sides. There are 2 Oxygen atoms in the LHS and 1 oxygen atom in the RHS. To balance oxygen atoms,
MnO₂ + HCl ⇒ MnCl₂ + 2 H₂O + Cl₂
Next, there is 1 Chlorine atom in the LHS and 4 chlorine atoms in the RHS. To balance chlorine atoms,
MnO₂ + 4 HCl ⇒ MnCl₂ + 2 H₂O + Cl₂
Now, there are 4 hydrogen atoms in the LHS and 4 hydrogen atoms in the RHS. So, they are balanced.
∴ Balanced equation = MnO₂ + 4 HCl ⇒ MnCl₂ + 2 H₂O + Cl₂
(b) P + HNO₃ ⇒ NO₂ + H₂O + H₃PO₄
To balance:
The number of P atoms is the same on both sides. There is 1 hydrogen atom in the LHS and 5 hydrogen atoms in the RHS. To balance hydrogen atoms,
P + 5 HNO₃ ⇒ NO₂ + H₂O + H₃PO₄
Now, there are 5 nitrogen atoms in the LHS and 1 nitrogen atom in the RHS. To balance nitrogen atoms,
P + 5 HNO₃ ⇒ 5 NO₂ + H₂O + H₃PO₄
Next, there are 15 oxygen atoms in the LHS and 15 oxygen atoms in the RHS. So, they are balanced.
∴ Balanced equation = P + 5 HNO₃ ⇒ 5 NO₂ + H₂O + H₃PO₄
(c) Mg₃N₂ + H₂O ⇒ Mg(OH)₂ + NH₃
To balance:
There are 3 magnesium atoms in the LHS and 1 magnesium atom in the RHS. To balance magnesium atoms,
Mg₃N₂ + H₂O ⇒ 3 Mg(OH)₂ + NH₃
There are 2 nitrogen atoms in the LHS and 1 nitrogen atom in the RHS. To balance nitrogen atoms,
Mg₃N₂ + H₂O ⇒ 3 Mg(OH)₂ + 2 NH₃
Now, there are 2 hydrogen atoms in the LHS and 12 hydrogen atoms in the RHS. To balance hydrogen atoms,
Mg₃N₂ + 6 H₂O ⇒ 3 Mg(OH)₂ + 2 NH₃
There are 6 oxygen atoms in the LHS and 6 oxygen atoms in the RHS. So, they are balanced.
∴ Balanced equation = Mg₃N₂ + 6 H₂O ⇒ 3 Mg(OH)₂ + 2 NH₃
(d) NH₃ + O₂ ⇒ N₂ + H₂O
To balance:
There is 1 nitrogen atom in the LHS and 2 nitrogen atoms in the RHS. To balance nitrogen atoms,
2 NH₃ + O₂ ⇒ N₂ + H₂O
There are 6 hydrogen atoms in the LHS and 2 hydrogen atoms in the RHS, To balance hydrogen atoms,
2 NH₃ + O₂ ⇒ N₂ + 3 H₂O
Now, there are 2 oxygen atoms in the LHS and 3 oxygen atoms in the RHS. To balance oxygen atoms,
2 NH₃ + 2 O₂ ⇒ N₂ + 3 H₂O Now there are 4 oxygen atoms in the LHS and 3 in the RHS. To balance, 2 NH₃ + 2 O₂ ⇒ N₂ + 4 H₂O
BY adding 4 before H₂O, the number of hydrogen atoms changed from 6 to 8 in the RHS. TO again balance hydrogen atoms,
4 NH₃ + 2 O₂ ⇒ N₂ + 4 H₂O
BY adding 4 before NH₃, the number of hydrogen atoms changed from 6 to 12 in the LHS (and0 the number of nitrogen atoms changed from 2 to 4 in the LHS. To balance both hydrogen and nitrogen atoms,
4 NH₃ + 2 O₂ ⇒ 2 N₂ + 6 H₂O
Now, the last step is to balance oxygen atoms. There are 4 atoms in the LHS and 6 atoms in the RHS. To balance,
4 NH₃ + 3 O₂ ⇒ 2 N₂ + 6 H₂O
∴ Balanced equation = 4 NH₃ + 3 O₂ ⇒ 2 N₂ + 6 H₂O
(e) Al(OH)₃ ⇒ Al₂O₃ + H₂O
To balance:
There is 1 aluminum atom in the LHS and 2 aluminum atoms in the RHS. To balance aluminum atoms,
2 Al(OH)₃ ⇒ Al₂O₃ + H₂O
Now, there are 6 hydrogen atoms in the LHS and 2 hydrogen atoms in the RHS. To balance hydrogen atoms,
2 Al(OH)₃ ⇒ Al₂O₃ + 3 H₂O
Next, the number of oxygen atoms on both sides of the equation is the same, i.e., 6.
∴ Balanced equation = 2 Al(OH)₃ ⇒ Al₂O₃ + 3 H₂O
(f) HNO₃ ⇒ H₂O + NO₂ + O₂
To balance:
There are 3 oxygen atoms in the LHS and 5 oxygen atoms in the RHS. To balance oxygen atoms,
4 HNO₃ ⇒ H₂O + NO₂ + O₂
Now, there are 4 hydrogen and nitrogen atoms in the LHS and 2 hydrogens, 1 nitrogen atom in the RHS. To balance both hydrogen and nitrogen atoms,
4 HNO₃ ⇒ 2 H₂O + 4 NO₂ + O₂
Now, there are 12 oxygen atoms in the LHS and 12 oxygen atoms {2+(4*2)+2} in the RHS. So, they are balanced.
∴ Balanced equation = 4 HNO₃ ⇒ 2 H₂O + 4 NO₂ + O₂
(g) Ca(OH)₂ + NH₄Cl ⇒ CaCl₂ + H₂O + NH₃
To balance:
The number of calcium atoms on both sides of the equation is the same, i.e., 1. There is 1 chlorine atom in the LHS and 2 chlorine atoms in the RHS. To balance chlorine atoms,
Ca(OH)₂ + 2 NH₄Cl ⇒ CaCl₂ + H₂O + NH₃
Now, there are 2 nitrogen atoms in the LHS and 1 nitrogen atom in the RHS. To balance nitrogen atoms,
Ca(OH)₂ + 2 NH₄Cl ⇒ CaCl₂ + H₂O + 2 NH₃
There are 2 oxygen atoms in the LHS and 1 atom in the RHS. To balance oxygen atoms,
Ca(OH)₂ + 2 NH₄Cl ⇒ CaCl₂ + 2 H₂O + 2 NH₃
Now, the number of hydrogen atoms on both sides of the equation is the same, i.e., 10.
∴ Balanced equation = Ca(OH)₂ + 2 NH₄Cl ⇒ CaCl₂ + 2 H₂O + 2 NH₃