Question

Determine the molar mass for the following compounds to four significant figures.

Short answer

Without the specific compounds' chemical formulas, it is impossible to provide exact molar masses. Once you provide the chemical formulas, you can determine their molar masses by calculating the sum of the products of each element's atomic mass and their respective quantities in the compound. Finally, round the result to four significant figures.

Step-by-step solution

Identify the chemical formula of the compound

Before we can find the molar mass, we must first know which compounds we are working with. Please provide the chemical formulas for the compounds in question.

Calculate the molar mass

Once the chemical formulas have been provided, you can proceed by finding the atomic masses of all the elements present in each compound. The atomic masses can be found in a periodic table. For each compound, multiply the atomic mass of each element by the number of atoms of that element in the compound's chemical formula. Finally, sum up the products for all elements within the compound to find the molar mass. Example: For the compound H2O (water), the molar mass is calculated as follows: Molar mass (H2O) = (2 * atomic mass of hydrogen) + (1 * atomic mass of oxygen) Molar mass (H2O) = (2 * 1.008) + (1 * 16.00) = 2.016 + 16.00 = 18.02 g/mol.

Round the molar mass to four significant figures

Round the molar mass calculated previously to four significant figures. In the example above, the molar mass is already to four significant figures. Please provide the chemical formulas for the compounds, and using the steps above, you can calculate the molar mass for each compound.

Key concepts

Chemical Formula

A chemical formula represents the elements present in a substance and the number of atoms of each element in a molecule. It's essential in determining the molar mass since it tells us exactly what atoms we need to account for. For example, the chemical formula for water is H₂O, indicating that each molecule of water consists of two hydrogen atoms and one oxygen atom. When working with chemical formulas, always ensure you're accurately counting the atoms, as this will affect calculations such as molar mass and chemical reactions.

• Subscript numbers in the formula indicate the number of atoms (e.g., H₂).
• If there is no subscript, it means there is only one atom of that element.
• Understanding formulas involves breaking down complex compounds into simpler representations.

Recognizing these aspects is crucial for calculating physical and chemical properties effectively.

Atomic Mass

Atomic mass is the mass of an atom, typically measured in atomic mass units (amu) and reflects the number of protons and neutrons in the nucleus. Each element has a distinct atomic mass, which you can find on the periodic table. In molar mass calculations, the atomic masses of elements in a compound are used to determine the total mass. For instance, the atomic mass of hydrogen is approximately 1.008 amu, and for oxygen, it's about 16.00 amu.

• Atomic masses are essential for calculating molar mass, which is the sum of all atomic masses in a compound.
• Since elements have isotopes, the atomic mass is often a weighted average based on natural abundance.
• Precision in atomic mass is vital for accurate calculations, especially in scientific settings.

By mastering atomic mass comprehension, you can perform accurate molar mass calculations in chemistry.

Significant Figures

Significant figures are the numbers that carry meaning contributing to a measurement's precision. In chemical calculations, maintaining the correct number of significant figures ensures the results accurately reflect the measurements' precision. When you round numbers, like in rounding molar masses, you should usually adhere to a specified number of significant figures, such as four, as detailed in your exercise.

• Start counting significant figures from the first non-zero digit.
• Trailing zeros in a decimal number are significant (e.g., 18.020 has five significant figures).
• Use significant figures to keep your calculations consistent with the precision of the given data.

Dealing correctly with significant figures eliminates errors caused by rounding too soon or too late during calculations.

Periodic Table

The periodic table is an organized chart of elements arranged by increasing atomic number. It's a vital tool in chemistry for quickly finding an element's atomic mass and other chemical properties. Each element's cell in the table contains important information, such as its symbol, atomic number, and atomic mass.

• Use the atomic mass from the periodic table for molar mass calculations.
• Elements are grouped into columns with similar chemical behaviors and properties.
• Understanding element placement can aid in predicting reactions and bonding behavior.

By utilizing the periodic table effectively, you streamline the process of identifying and calculating complex chemical properties.