Ch.3 - Chemical Reactions and Reaction Stoichiometry

Brown - Chemistry: The Central Science 15th Edition

Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970Not the one you use?Change textbook

Brown 15th Edition

Ch.3 - Chemical Reactions and Reaction Stoichiometry

Problem 28a

Chapter 3, Problem 28a

Calculate the percentage of carbon by mass in each of the compounds represented by the following models: (a)

Verified step by step guidance

Step 1: Identify the molecular formula of the compound. This information is usually given in the problem or can be determined from the model.

Step 2: Calculate the molar mass of the compound. This is done by adding up the atomic masses of all the atoms in the compound. The atomic masses can be found on the periodic table.

Step 3: Calculate the molar mass of the carbon in the compound. This is done by multiplying the atomic mass of carbon (approximately 12.01 g/mol) by the number of carbon atoms in the compound.

Step 4: Divide the molar mass of the carbon by the molar mass of the compound and multiply by 100 to get the percentage of carbon by mass in the compound.

Step 5: Repeat the process for each compound in the problem.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all the atoms in a molecule. Understanding molar mass is essential for determining the mass percentage of an element in a compound, as it provides the necessary context for comparing the mass of the element to the total mass of the compound.

Mass Percentage

Mass percentage is a way of expressing the concentration of an element in a compound, calculated by dividing the mass of the element by the total mass of the compound and multiplying by 100. This concept is crucial for the question, as it directly relates to how to quantify the proportion of carbon in the given compounds, allowing for a clear comparison of elemental composition.

Chemical Formulas

Chemical formulas represent the composition of a compound, indicating the types and numbers of atoms present. For example, in the formula C2H6, there are two carbon atoms and six hydrogen atoms. Understanding how to interpret chemical formulas is vital for identifying the elements involved and calculating their respective contributions to the overall mass of the compound.

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