Class 10 Chemistry Worksheet Chemical Reactions and Equations

In chemistry, everything revolves around changes. Whether it’s cooking food, rusting iron, or burning wood, chemical reactions make these transformations possible. Chapter 1 introduces you to the world of chemical reactions, their characteristics, and how we represent them with chemical equations. By the end of this worksheet, you’ll not only understand how to write and balance chemical equations but also classify reactions and explore practical phenomena like corrosion and rancidity.

What is a Chemical Reaction?

A chemical reaction is a process where one or more substances (called reactants) change into new substances (called products).

For example:

• Magnesium burns in air to form magnesium oxide:

 

$$2Mg + O_2 \rightarrow 2MgO$$

Characteristics of a Chemical Reaction

The following signs indicate that a chemical reaction has occurred:

1. Change in State: Formation of gas, liquid, or solid.
   • Example: Steam condensing into liquid water.
2. Change in Color: A visible color change occurs.
   • Example: Rusting of iron changes the color to reddish-brown.
3. Evolution of Gas: Gas bubbles are produced during the reaction.
   • Example: Effervescence in vinegar and baking soda reaction.
4. Change in Temperature: Heat is absorbed or released.
   • Example: Burning of coal releases heat.
5. Formation of Precipitate: An insoluble solid forms in a liquid reaction.
   • Example: Mixing barium chloride and sulfuric acid forms a white precipitate of barium sulfate.

CBSE Class 10 Worksheet – Chemical Reactions and Equations

1. What are the key features of a chemical reaction?
2. Identify the type of change (color, gas, or precipitate) in the following reactions:
   • Zinc reacting with hydrochloric acid.
   • Copper sulfate reacting with iron.

Writing and Balancing Chemical Equations

2.1 Chemical Equations

Chemical reactions are represented by chemical equations using symbols and formulas.

• Example: Hydrogen reacts with oxygen to form water.
  $$2H_2+O_2\to 2H_{2}O$$

   

2.2 Balancing Chemical Equations

According to the Law of Conservation of Mass, the total mass of reactants must equal the total mass of products. To ensure this, chemical equations are balanced.

Steps to Balance an Equation:

1. Write the skeleton equation.
2. Count the number of atoms of each element on both sides.
3. Adjust coefficients to balance atoms.
4. Double-check the balance.

• Unbalanced Example:
  $$H_2+O_2\to H_{2}O$$

   

• Balanced Equation:
  $$2H_2+O_2\to 2H_{2}O$$

   

Chemical Reactions and Equations Class 10 Woksheet

• Balance the following equations:

 

$$Fe+O_2\to F{e}_2{O}_3$$ $$KCl{O}_3\to KCl+O_{\mathrm{2<span\; style="font-family:\; Georgia,\; \text{'}Times\; New\; Roman\text{'},\; \text{'}Bitstream\; Charter\text{'},\; Times,\; serif;\; font-size:\; 16px;"></span>}}$$

• Write the chemical equations for:
• • Reaction of magnesium with oxygen.
  • Reaction of calcium carbonate with hydrochloric acid.

Types of Chemical Reactions

3.1 Combination Reaction

In a combination reaction, two or more reactants combine to form one product.

Example:

$$2H_2+O_2\to 2H_{2}O$$

3.2 Decomposition Reaction

A decomposition reaction involves breaking down a single compound into simpler substances.

Example:

$$2H_{2}O\to 2H_2+O_{\mathrm{2<span\; style="font-family:\; Georgia,\; \text{'}Times\; New\; Roman\text{'},\; \text{'}Bitstream\; Charter\text{'},\; Times,\; serif;\; font-size:\; 16px;"></span>}}$$

3.3 Displacement Reaction

In a displacement reaction, one element replaces another in a compound.

Example:

$$Zn+CuS{O}_4\to ZnS{O}_4+Cu$$

3.4 Double Displacement Reaction

A double displacement reaction involves the exchange of ions between two compounds.

Example:

$$NaCl+AgN{O}_3\to NaN{O}_3+AgCl$$

3.5 Redox Reaction

Oxidation and reduction occur simultaneously in a redox reaction.

Example:

$$Zn+H_{2}S{O}_4\to ZnS{O}_4+H_{\mathrm{2<span\; style="font-family:\; Georgia,\; \text{'}Times\; New\; Roman\text{'},\; \text{'}Bitstream\; Charter\text{'},\; Times,\; serif;\; font-size:\; 16px;"></span>}}$$

Class 10 Chemical Reactions and Equations Worksheet

• Identify the type of reaction:

 

$$2KCl{O}_3\to 2KCl+3O_{\mathrm{2<span\; style="font-family:\; Georgia,\; \text{'}Times\; New\; Roman\text{'},\; \text{'}Bitstream\; Charter\text{'},\; Times,\; serif;\; font-size:\; 16px;"></span>}}$$ $$2Na+C{l}_2\to 2NaCl$$

 

• Write one example each for combination, decomposition, and displacement reactions.

Corrosion and Rancidity

4.1 Corrosion

Corrosion is the gradual destruction of metals due to chemical reactions with the environment.

• Example: Rusting of iron:
  $$4Fe + 3O_2 + 6H_2O \rightarrow 4Fe(OH)_3$$

   

  4Fe+3O2​+6H2​O→4Fe(OH)3​

4.2 Rancidity

Rancidity is the spoiling of food due to the oxidation of fats and oils.

Methods to Prevent Rancidity:

1. Store food in airtight containers.
2. Add antioxidants.
3. Refrigerate food.

Worksheet for Chemical Reactions and Equations Class 10

1. Explain the process of rusting in your own words.
2. List three methods to prevent food rancidity.

More Chemical Reactions & Equations Class 10 Worksheet

Higher Order Thinking Skills (HOTs)

1. Why is it important to balance chemical equations?
2. How does double displacement differ from displacement reactions?
3. Why are nitrogen gas packets used to store chips?

Fill in the Blanks

1. A chemical reaction involves a change in __________ and the formation of new substances.
2. The gradual destruction of metals by environmental reactions is called __________.
3. __________ reactions involve the exchange of ions between two compounds.

Match the Following

True or False

1. All chemical reactions produce heat. ( )
2. Decomposition reactions involve one product breaking down. ( )
3. Rusting is a type of chemical reaction. ( )