NDA » NDA Study Material » Chemistry » Make notes on the equation-based problem

Make notes on the equation-based problem

The article contains equation-based problems, How to solve problems based on chemical equations, examples showing how to change the unbalanced chemical equations into balanced chemical equations.

Balancing a chemical equation is significant for studying chemical reactions. An equation is a mathematical statement. It contains addition, subtraction and equal symbol. Equation based problem is a symbolic representation of problems. A balanced chemical equation is useful in solving problems based on chemical equations. The symbolic representation of a chemical reaction is called a balanced chemical equation. 

Body

There are many equation-based problems in chemistry. There is a difference between molecular, complete ionic, and net ionic equations. The similarity between molecular, complete ionic and net ionic equations is that they all have coefficient, subscriptions and addition symbols. 

For three reasons, unbalanced chemical equations are made into balanced chemical equations. They are the following.

  • A balanced Chemical equation precisely addresses what happens when we notice the synthetic response in reality.

  • A balanced Chemical equation complies with the Law of conservation of Mass. This is a sign directing heads in science.

  • A balanced Chemical equation eases up foreseeing how much reactants are required and how many items are framed.

Some of the chemical equation problems and solutions are given below.

Problem

Write a balanced chemical equation for molecular nitrogen (N2) and oxygen (O2) reactions to form dinitrogen pentoxide.

Solution

Count the quantity of each sort of iota present in the unequal condition.

Unbalanced equation  = N2 + O⟶  N2O5

Element Reactants Products Balanced

N               1 × 2 = 2 1 × 2 = 2       2 = 2, yes

O               1 × 2 = 2        1 × 5 = 5   2 ≠ 5, no

However, nitrogen is balanced, changes in coefficients are expected to adjust the number of oxygen molecules. To adjust the number of oxygen molecules, a sensible first endeavour is to change the coefficients for the O2 and N2 O5 to numbers that will yield 10 O particles (the most un-normal numerous for the O iota addendums in these two recipes).

Unbalanced equation  =  N2 + 5O⟶  2N2O5

Element          Reactants       Products               Balanced

N             1 × 2 = 2       2 × 2 = 4               2 ≠ 4, no

O             5 × 2 = 10       2 × 5 = 10              10 = 10, yes 

The N atom has to be reestablished by changing the coefficient for the reactant N2 to 2.

2N2 + 5O⟶  2N2O5

Elements /Reactants  /Products /Balanced                                               

Nitrogen / 2 × 2 = 4  /   2 × 2 = 4/  4 = 4, yes

Oxygen/  5 × 2 = 10/ 2 × 5 = 10/10 = 10,yes

The quantities of N and O iotas on one or the other side of the situation are presently equivalent. Thus the condition is adjusted.

In this way, the adjusted compound condition for the response of sub-atomic nitrogen (N2) and oxygen (O2) to shape dinitrogen pentoxide is 2N2 + 5O⟶  2N2O5

Problem 

Write a balanced chemical equation for the decomposition of ammonium nitrate (NH4NO3) to form molecular nitrogen (N2), molecular oxygen (O2), and water (H2O)

Solution

Unbalanced equation  = NH4NO3 ⟶  N2 + O2 + H2O

Just change the coefficients (numbers in front substances)

Never change the addendums (little numbers after components)

Count the quantity of each kind of iota present in NH4NO

Element Balanced

N               2 × 2 = 4    

H                       4 x 2 = 8

O                       3 x 2 = 6

Count the quantity of each kind of iota present in N2 + O2 + H2O

Element Balanced

N               2 × 2 = 4  

O               2 + 4 = 6        

H                       2 + 2 = 4

Therefore, to balance the following chemical equation for the decomposition of ammonium nitrate (NH4NO3) to form molecular nitrogen (N2), molecular oxygen (O2), and water (H2O) is 2NH4NO3 ⟶  2N2 + O2 + 4H2O

Problem

Whenever carbon dioxide is broken up in a fluid arrangement of sodium hydroxide, the blend responds to yield watery sodium carbonate and liquid water. Compose balanced molecular, complete ionic, and net ionic equations for this cycle.

Solution 

Unbalanced equation = CO2(aq) + NaOH(aq) ⟶Na2CO3(aq) +H2O(l)

Balanced equation is given below

2NaCl(aq) + 2H2O ⟶ 2NaOH(aq) +H2(g) + Cl2(g) (molecular)

2Na + (aq) + 2Cl (aq) + 2H2O ⟶ 2Na+ (aq) + 2OH(aq)+ H2 (g)+ Cl2(g) (complete ionic)

2Cl(aq) + 2H2O ⟶ 2OH(aq) + 2H2(g) + Cl2(g) (net ionic)

Conclusion 

A balanced chemical equation is an important topic in chemistry. Questions from equation-based problems are frequently asked in exams. Some of the unbalanced equations are PCl5 (s) + H2O (1) → POCl3(l) + HCl (aq), Cu(s) + HNO3 (aq) → Cu (NO3)2 (aq) + H2O (l) + NO(g),   H2 (g) + I2 (s) → HI (s),  Fe (s) + O(g) → Fe2O3 (s), Na (s) + H2O(l) →  N2OH (aq) + H2(g). The actual conditions of reactants and items in compound conditions frequently are shown with an incidental condensing following the equations. Normal shortenings incorporate s for solids, l for fluids, g for gases, and aq for substances broken down in the water.

faq

Frequently asked questions

Get answers to the most common queries related to the NDA Examination Preparation.

What is the balanced equation?

Ans: Compound condition with equivalent quantities of iotas for every component in the response and item is ...Read full

What is a chemical equation?

Ans: The symbolic portrayal of a substance response is called a chemical equation....Read full

Can we change the coefficients while balancing the chemical equation?

Ans: We change the coefficients, i.e., numbers, in front of substances to balance the following che...Read full

Can we change the subscripts while balancing the chemical equation?

Ans: No, we cannot change the subscripts, i.e., small numbers after elements, to balance the chemical equati...Read full

Can we make every unbalanced chemical equation into a balanced chemical equation?

Ans: Yes,  we can make every unbalanced chemical equation into a balanced chemical equation....Read full

What is a molecular equation?

Ans: A molecular equation is a chemical equation where all reactants and items are addressed as non...Read full

When is an equation becomes balanced?

Ans: An equation becomes balanced when a similar number of every component is addressed on the reac...Read full