Question

According to the law of conservation of mass, if element A has an atomic mass of 2 mass units and element B has an atomic mass of 3 mass units, what mass would be expected for compound AB? for compound \(\mathrm{A}_{2} \mathrm{B}_{3}\) ?

Short answer

The mass of compound AB is 5 mass units, and the mass of compound \( \text{A}_2\text{B}_3 \) is 13 mass units.

Step-by-step solution

- Understand the Law of Conservation of Mass

The Law of Conservation of Mass states that mass cannot be created or destroyed in a chemical reaction. Therefore, the total mass of the reactants must equal the total mass of the products.

- Determine the Mass of Compound AB

To find the mass of compound AB, add the atomic masses of elements A and B. Element A has an atomic mass of 2 mass units and element B has an atomic mass of 3 mass units. Thus, the mass of AB is: \( \text{Mass of AB} = 2 + 3 = 5 \text{ mass units} \)

- Determine the Mass of Compound \( \text{A}_2\text{B}_3 \)

To find the mass of compound \( \text{A}_2\text{B}_3 \), calculate the total mass of two atoms of element A and three atoms of element B. \( 2 \times \text{Atomic mass of A} = 2 \times 2 = 4 \text{ mass units} \) \( 3 \times \text{Atomic mass of B} = 3 \times 3 = 9 \text{ mass units} \) Add these values together to find the total mass of \( \text{A}_2\text{B}_3 \): \( \text{Mass of } \text{A}_2\text{B}_3 = 4 + 9 = 13 \text{ mass units} \)

Key concepts

atomic mass

Atomic mass is a key concept in understanding the Law of Conservation of Mass and chemical reactions. It is the mass of a single atom of a chemical element, usually expressed in atomic mass units (amu). To make sense of atomic mass:

• Each element on the periodic table has a unique atomic mass.
• It accounts for the total mass of protons and neutrons in an atom's nucleus.

For elements A and B in the exercise, the atomic masses are 2 amu and 3 amu, respectively. Knowing these values helps you calculate the mass of compounds they form, as outlined in the solution.

chemical reactions

A chemical reaction involves the transformation of reactant substances into products. According to the Law of Conservation of Mass, the total mass of the reactants equals the total mass of the products. Key points about chemical reactions:

• Involves breaking and forming chemical bonds.
• No atoms are lost or gained; they are simply rearranged.
• Mass remains constant throughout the reaction.

Understanding these principles is crucial for calculating the mass of products, such as compound AB and compound \(\text{A}_2\text{B}_3\) in the example.

compound mass calculation

Compound mass calculation is essential for applying the Law of Conservation of Mass in chemical reactions. To calculate compound mass:

• Sum up the atomic masses of all atoms in the compound.
• Use the atomic mass units (amu) for precision.
• Ensure mass conservation by balancing both sides of the reaction.

For compound AB: The mass is the sum of A (2 amu) and B (3 amu), resulting in 5 amu. For compound \(\text{A}_2\text{B}_3\): Calculate the mass of 2 atoms of A (\(2 \ times 2 = 4\) amu) and 3 atoms of B (\(3 \ times 3 = 9\) amu). Adding them gives 13 amu. This method guarantees accuracy in any compound mass calculation.