Chapter 9: Problem 14
State the molar mass for each of the following: (a) arsenic, As (b) germanium, Ge (c) ozone, \(\mathrm{O}_{3}\) (d) phosphorus, \(P_{4}\)
Short Answer
Expert verified
(a) 74.92 g/mol, (b) 72.63 g/mol, (c) 48.00 g/mol, (d) 123.88 g/mol.
Step by step solution
01
Molar Mass of Arsenic
The molar mass of an element corresponds to the mass of one mole of that element. According to the periodic table, the atomic mass of arsenic (As) is approximately 74.92 g/mol.
02
Molar Mass of Germanium
Similarly, to find the molar mass of germanium (Ge), refer to the periodic table. The atomic mass of germanium is approximately 72.63 g/mol.
03
Molar Mass of Ozone
Ozone is a molecule consisting of three oxygen atoms. The atomic mass of oxygen (O) is approximately 16.00 g/mol. Therefore, the molar mass of ozone (\(O_3\)) is calculated as: \(3 \times 16.00 = 48.00\) g/mol.
04
Molar Mass of Phosphorus
Phosphorus typically exists as \(P_4\). The atomic mass of phosphorus (P) is approximately 30.97 g/mol. Therefore, the molar mass of \(P_4\) is calculated as: \(4 \times 30.97 = 123.88\) g/mol.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Periodic Table
The periodic table is a powerful tool in chemistry and forms the foundation for understanding many scientific concepts. It organizes all known chemical elements in a structured format. This format is based on increasing atomic number, which is the number of protons in an atom’s nucleus. Each element has its own unique square in the table, providing important information about that element, such as its symbol, atomic number, and atomic mass.
One of the key advantages of the periodic table is that it allows chemists to quickly access the atomic mass of elements, which is crucial for calculating molar mass. For instance, by simply looking at the periodic table, you can determine the atomic mass of arsenic (As) as 74.92 g/mol.
It's important to get familiar with reading the periodic table, as it helps in understanding the relationships between different elements and their properties. Elements are grouped into columns known as "groups" or "families," which often share similar chemical behaviors. This makes the periodic table not just a chart but a highly informative source for chemical analysis.
One of the key advantages of the periodic table is that it allows chemists to quickly access the atomic mass of elements, which is crucial for calculating molar mass. For instance, by simply looking at the periodic table, you can determine the atomic mass of arsenic (As) as 74.92 g/mol.
It's important to get familiar with reading the periodic table, as it helps in understanding the relationships between different elements and their properties. Elements are grouped into columns known as "groups" or "families," which often share similar chemical behaviors. This makes the periodic table not just a chart but a highly informative source for chemical analysis.
Atomic Mass
Atomic mass, sometimes referred to as atomic weight, is the weighted average mass of the atoms in a naturally occurring element. It is measured in atomic mass units (amu) and usually expressed in grams per mole (g/mol).
The atomic mass of an element takes into account the different isotopes and their abundance found in nature. This is why, for example, the atomic mass of oxygen is approximately 16.00 g/mol, even though some oxygen atoms exist as heavier isotopes.
Knowing the atomic mass is essential for calculating the molar mass of substances. In our example, the atomic mass of germanium is approximately 72.63 g/mol, which directly tells us that one mole of germanium atoms would weigh around 72.63 grams.
For chemical reactions and mole calculations, understanding and using atomic masses from the periodic table is a fundamental skill, leading to more accurate and meaningful scientific analyses.
The atomic mass of an element takes into account the different isotopes and their abundance found in nature. This is why, for example, the atomic mass of oxygen is approximately 16.00 g/mol, even though some oxygen atoms exist as heavier isotopes.
Knowing the atomic mass is essential for calculating the molar mass of substances. In our example, the atomic mass of germanium is approximately 72.63 g/mol, which directly tells us that one mole of germanium atoms would weigh around 72.63 grams.
For chemical reactions and mole calculations, understanding and using atomic masses from the periodic table is a fundamental skill, leading to more accurate and meaningful scientific analyses.
Molecular Mass
Molecular mass, also known as molecular weight, is the sum of the atomic masses of the atoms in a molecule. It helps in understanding the mass of a single molecule, as opposed to the molar mass, which is concerned with one mole of molecules.
To calculate the molecular mass of a compound, add up the atomic masses of all atoms that make up the molecule. For instance, ozone (\(O_3\)) consists of three oxygen atoms. Knowing the atomic mass of oxygen is about 16.00 g/mol, we calculate the molecular mass of ozone as \(3 \times 16.00 = 48.00\) g/mol.
This concept is vital when dealing with molecular compounds as it facilitates the determination of how much space a given number of molecules might occupy, how they might behave in a chemical reaction, and other important properties.
To calculate the molecular mass of a compound, add up the atomic masses of all atoms that make up the molecule. For instance, ozone (\(O_3\)) consists of three oxygen atoms. Knowing the atomic mass of oxygen is about 16.00 g/mol, we calculate the molecular mass of ozone as \(3 \times 16.00 = 48.00\) g/mol.
This concept is vital when dealing with molecular compounds as it facilitates the determination of how much space a given number of molecules might occupy, how they might behave in a chemical reaction, and other important properties.
Element Calculation
Element calculation is a fundamental skill in chemistry, allowing us to determine the amount of an element or compound in a sample by calculating its molar mass. This requires a good understanding of both atomic and molecular masses, as well as the ability to accurately interpret information from the periodic table.
As seen in our exercise, calculating the molar mass of molecules like phosphorus \(P_4\) involves summing the atomic masses of involved atoms. For phosphorus, the atomic mass is approximately 30.97 g/mol, and since \(P_4\) consists of four phosphorus atoms, its molar mass would be \(4 \times 30.97 = 123.88\) g/mol.
Thoroughly grasping element calculation techniques enables you to handle a wide range of scientific tasks, from balancing chemical equations to analyzing the results of a lab experiment. It forms the building block for quantitative chemistry.
As seen in our exercise, calculating the molar mass of molecules like phosphorus \(P_4\) involves summing the atomic masses of involved atoms. For phosphorus, the atomic mass is approximately 30.97 g/mol, and since \(P_4\) consists of four phosphorus atoms, its molar mass would be \(4 \times 30.97 = 123.88\) g/mol.
Thoroughly grasping element calculation techniques enables you to handle a wide range of scientific tasks, from balancing chemical equations to analyzing the results of a lab experiment. It forms the building block for quantitative chemistry.
