In stoichiometric calculations, what is the mass of 1 mole of carbon dioxide (CO2) expressed in grams?

Introduction / Context:
This fundamental chemistry question checks your ability to calculate molar mass from a chemical formula. Molar mass is essential for converting between moles and grams in stoichiometry, gas law calculations and solution chemistry. Carbon dioxide is a common compound that appears in many exam problems and real world contexts such as respiration and combustion.

Given Data / Assumptions:
- The formula of carbon dioxide is CO2.
- We use approximate atomic masses: carbon ≈ 12 u, oxygen ≈ 16 u.
- The question asks for the mass of 1 mole of CO2 in grams, which equals the molar mass.

Concept / Approach:
Molar mass of a compound is found by summing the atomic masses of all atoms in its formula. For CO2, this means adding the mass of one carbon atom and two oxygen atoms. Once we have the molar mass in atomic mass units (u), the numerical value in grams per mole is the same. Therefore, the mass of 1 mole of CO2 is simply its molar mass expressed in grams.

Step-by-Step Solution:
Step 1: Identify the atoms in CO2: one carbon atom and two oxygen atoms. Step 2: Use approximate atomic masses: carbon = 12, oxygen = 16. Step 3: Calculate the contribution from carbon: 1 * 12 = 12. Step 4: Calculate the contribution from oxygen: 2 * 16 = 32. Step 5: Add these values to obtain molar mass: 12 + 32 = 44. Step 6: Conclude that the molar mass of CO2 is 44 g mol^-1, so 1 mole of CO2 has a mass of 44 grams.

Verification / Alternative check:
This value is widely used in many chemistry and physics problems, such as calculating the mass of CO2 produced in combustion reactions or determining the number of moles in a given mass of dry ice. If you recall that oxygen gas (O2) has a molar mass of 32 g mol^-1 and that CO2 contains one carbon (12) plus two oxygens (32), the total of 44 is straightforward and consistent. Any significantly different value would contradict well established molar mass tables.

Why Other Options Are Wrong:
32 grams: This is the molar mass of O2, not CO2; it counts only two oxygens and omits the carbon contribution.
16 grams: Represents approximately the mass of one oxygen atom per mole, far too low for CO2.
12 grams: Represents the molar mass of elemental carbon, not carbon dioxide.

Common Pitfalls:
One common mistake is to forget to multiply the atomic mass of oxygen by 2 in CO2 and incorrectly use 16 instead of 32 for the oxygen part. Another error is to confuse CO2 with CO or O2 when recalling numbers from memory. To avoid such problems, always write the formula clearly, list each element with its subscript and multiply atomic masses by the appropriate subscripts before summing.

Final Answer:
The mass of 1 mole of carbon dioxide (CO2) is 44 grams.