Write balanced equations for the formation of the following compounds from their elements. (c) Dichloromethane (a liquid, CH2Cl2)

Verified step by step guidance

1. Identify the elements involved in the formation of dichloromethane, which are carbon (C), hydrogen (H), and chlorine (Cl).
2. Write the unbalanced equation using the molecular formula of dichloromethane (CH2Cl2) and the elemental forms of carbon, hydrogen, and chlorine. The elemental form of carbon is solid carbon (C), hydrogen is dihydrogen (H2), and chlorine is dichlorine (Cl2). The unbalanced equation is: C(s) + H2(g) + Cl2(g) → CH2Cl2(l).
3. Balance the carbon atoms first. Since there is one carbon atom in CH2Cl2 and one in elemental carbon, the carbon atoms are already balanced.
4. Next, balance the hydrogen atoms. There are two hydrogen atoms in CH2Cl2 and two in one molecule of dihydrogen (H2), so the hydrogen atoms are balanced with one molecule of H2.
5. Finally, balance the chlorine atoms. There are two chlorine atoms in CH2Cl2 and two in one molecule of dichlorine (Cl2), so the chlorine atoms are balanced with one molecule of Cl2. The balanced chemical equation is: C(s) + H2(g) + Cl2(g) → CH2Cl2(l).

Key Concepts

Balanced Chemical Equations

A balanced chemical equation represents a chemical reaction where the number of atoms for each element is the same on both sides of the equation. This is crucial for obeying the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction. Balancing involves adjusting coefficients in front of compounds to ensure that the total number of each type of atom is equal.

Formation Reactions

A formation reaction is a specific type of chemical reaction where a compound is formed from its constituent elements in their standard states. For example, when forming dichloromethane (CH2Cl2), chlorine gas (Cl2) and carbon (C) in its solid form, along with hydrogen gas (H2), are combined. Understanding formation reactions is essential for writing accurate equations for compound synthesis.

Standard States of Elements

The standard state of an element refers to its physical state and form at a specified temperature and pressure, typically 25°C and 1 atm. For example, carbon is solid (graphite), hydrogen is a gas (H2), and chlorine is also a gas (Cl2) at these conditions. Recognizing the standard states of elements is vital for correctly writing formation reactions and ensuring that the reactants are represented accurately.