Question

When small amounts of acetylene gas are needed, a common process is to react calcium carbide with water. Acetylene gas is evolved rapidly from this combination even at room temperature, leaving a residue of calcium hydroxide. Write the balanced chemical equation for this process.

Short answer

The balanced chemical equation for the reaction between calcium carbide and water is: \( CaC_2 + 2H_2O \rightarrow C_2H_2 + Ca(OH)_2 \)

Step-by-step solution

Determine the reactants and products

The given reaction involves calcium carbide (CaC2) reacting with water (H2O) to produce acetylene gas (C2H2) and calcium hydroxide (Ca(OH)2).

Write the unbalanced chemical equation

The unbalanced chemical equation can be written as follows: CaC2 + H2O → C2H2 + Ca(OH)2

Balance the chemical equation

To balance the chemical equation, we need to ensure that there are equal numbers of each type of atom on both sides of the equation. We can do this by adjusting the coefficients in front of each compound. 1. There are equal numbers of Ca atoms on both sides of the equation, so there is no need to adjust these. 2. The number of carbon atoms on both sides is two, so these are balanced. 3. On the left-hand side of the equation, there are two hydrogen atoms, while there are four on the right-hand side. To balance the hydrogen atoms, we need to multiply the coefficient of the water molecule (H2O) by 2: CaC2 + 2H2O → C2H2 + Ca(OH)2 Now, the chemical equation is balanced. There are equal numbers of each type of atom on both sides of the equation: 1 Ca, 2 C, and 4 H atoms on both the left and right sides of the equation. Therefore, the final balanced chemical equation is: CaC2 + 2H2O → C2H2 + Ca(OH)2

Key concepts

Acetylene Production

Acetylene is a valuable gas used in various industrial applications. It is highly flammable and is mainly utilized for welding and as a raw material for chemical synthesis.
The production of acetylene gas is often achieved by the reaction between calcium carbide and water. When calcium carbide (CaC2) comes in contact with water (H2O), acetylene gas (C2H2) is rapidly released.
This method is popular for producing small quantities of acetylene due to its simplicity and efficiency.
Some key points about acetylene production include:

• Acetylene is produced instantly at room temperature.
• It requires minimal equipment, making it accessible for smaller-scale needs.
• The process leaves behind calcium hydroxide as a byproduct.

Understanding the basics of acetylene production helps in comprehending the practical applications and safety measures required when handling this reactive gas.

Calcium Carbide Reaction

Calcium carbide is a grayish-black solid compound widely used to generate acetylene gas through a chemical reaction with water. This reaction is straightforward yet fascinating due to the rapid evolution of gas it produces.
The initial step involves identifying the reactants: calcium carbide (CaC2) and water (H2O).
When these two come into contact, a vigorous chemical reaction occurs, producing acetylene gas (C2H2) and calcium hydroxide (Ca(OH)2) as the products.
Here are some key details:

• The reaction is exothermic, releasing heat which aids the process.
• The reaction formulation: \[ \text{CaC}_2 + 2 \text{H}_2\text{O} \rightarrow \text{C}_2\text{H}_2 + \text{Ca(OH)}_2 \]
• Calcium carbide effectively acts as a solid source of acetylene when water is added.

By comprehending the calcium carbide reaction, we gain insights into how simple chemical processes can be used for practical purposes.

Chemical Reactions

Chemical reactions are processes where substances (reactants) change into new substances (products) with different compositions and properties.
Understanding how to balance these reactions is vital in chemistry, as it allows us to adhere to the law of conservation of mass.
The reaction between calcium carbide and water to form acetylene and calcium hydroxide is a perfect example of a simple yet significant chemical reaction.
Here are some important aspects to consider when studying chemical reactions:

• Each side of the chemical equation must have an equal number of each type of atom, ensuring mass is conserved.
• Balancing chemical equations often requires adjusting coefficients to equalize atom counts between reactants and products.
• Understanding chemical reactions provides insight into complex transformations occurring in nature and industry.

Learning to balance and analyze chemical reactions empowers students to explore deeper into the interactions of matter on a molecular level.