find the percent composition of br in cubr2

find the percent composition of br in cubr2

Let’s delve into the intricate world of stoichiometry and explore how to find the percentage of bromine (Br) in copper(II) bromide (CuBr₂).

To begin with, understanding the concept of percent composition involves calculating the ratio of the mass of each element present in a compound relative to the total mass of the compound. In this case, we’re interested in determining the percentage of bromine in copper(II) bromide (CuBr₂). This task requires us to first comprehend the chemical formula and then apply the principles of atomic weights and molar masses.

Firstly, let’s consider the molecular structure of CuBr₂. Each molecule of copper(II) bromide contains one copper atom and two bromine atoms. To determine the percent composition, we need to calculate the molar mass of CuBr₂. The atomic weight of copper (Cu) is approximately 63.55 g/mol, while that of bromine (Br) is about 79.904 g/mol. Therefore, the molar mass of CuBr₂ can be calculated as follows:

[ \text{Molar mass of CuBr₂} = (\text{Atomic weight of Cu}) + 2 \times (\text{Atomic weight of Br}) ] [ \text{Molar mass of CuBr₂} = 63.55 , \text{g/mol} + 2 \times 79.904 , \text{g/mol} ] [ \text{Molar mass of CuBr₂} = 63.55 , \text{g/mol} + 159.808 , \text{g/mol} ] [ \text{Molar mass of CuBr₂} = 223.358 , \text{g/mol} ]

Next, we need to find the mass of bromine in one mole of CuBr₂. Since there are two bromine atoms in each molecule, the mass of bromine in one mole of CuBr₂ is:

[ \text{Mass of bromine in CuBr₂} = 2 \times (\text{Atomic weight of Br}) ] [ \text{Mass of bromine in CuBr₂} = 2 \times 79.904 , \text{g/mol} ] [ \text{Mass of bromine in CuBr₂} = 159.808 , \text{g/mol} ]

Finally, to find the percent composition of bromine, we use the following formula:

[ \text{Percent composition of Br} = \left( \frac{\text{Mass of bromine}}{\text{Molar mass of CuBr₂}} \right) \times 100% ] [ \text{Percent composition of Br} = \left( \frac{159.808 , \text{g/mol}}{223.358 , \text{g/mol}} \right) \times 100% ] [ \text{Percent composition of Br} \approx 71.40% ]

Thus, the percent composition of bromine in copper(II) bromide (CuBr₂) is approximately 71.40%.

Questions & Answers

  1. Q: What is the formula for calculating the percent composition of an element in a compound?

    • A: The formula for calculating the percent composition of an element in a compound is given by: [ \text{Percent composition of X} = \left( \frac{\text{Mass of X}}{\text{Molar mass of compound}} \right) \times 100% ] where (X) represents the element whose percent composition you are trying to find.

  2. Q: How do you find the molar mass of a compound like CuBr₂?

    • A: The molar mass of a compound is found by summing the atomic weights of all the atoms in the compound’s formula. For CuBr₂, it’s the sum of the atomic weight of copper (Cu) and twice the atomic weight of bromine (Br).

  3. Q: Why is it important to know the percent composition of elements in compounds?

    • A: Knowing the percent composition helps in understanding the structural makeup of a substance and its elemental content, which is crucial in fields such as chemistry, materials science, and environmental studies. It aids in predicting properties, formulating reactions, and analyzing samples.