How many atoms of carbon are present in 6.81 grams of carbon monoxide, CO? How many grams of oxygen are present in 2.50×10^22 molecules of carbon monoxide?
The Correct Answer and Explanation is:
Question 1: How many atoms of carbon are present in 6.81 grams of carbon monoxide (CO)?
Step 1: Find the molar mass of CO
- Carbon (C) = 12.01 g/mol
- Oxygen (O) = 16.00 g/mol
Total molar mass of CO = 12.01 + 16.00 = 28.01 g/mol
Step 2: Find moles of CO in 6.81 grams
Moles of CO = Mass of CO ÷ Molar mass of CO
Moles of CO = 6.81 g ÷ 28.01 g/mol ≈ 0.243 moles CO
Step 3: Find number of carbon atoms
Each molecule of CO contains one atom of carbon. Therefore:
- 1 mole of CO = 6.022 × 10²³ molecules of CO
- 0.243 moles of CO × 6.022 × 10²³ = 1.463 × 10²³ carbon atoms
Final Answer:
1.463 × 10²³ atoms of carbon
Question 2: How many grams of oxygen are present in 2.50 × 10²² molecules of CO?
Step 1: Find moles of CO
Moles of CO = Number of molecules ÷ Avogadro’s number
Moles of CO = 2.50 × 10²² ÷ 6.022 × 10²³ ≈ 0.0415 moles CO
Step 2: Find moles of oxygen atoms
Each CO molecule contains one oxygen atom. So, moles of oxygen atoms = moles of CO = 0.0415 moles
Step 3: Find mass of oxygen
Mass = Moles × Molar mass of oxygen
Mass = 0.0415 moles × 16.00 g/mol ≈ 0.664 grams
Final Answer:
0.664 grams of oxygen
Summary Explanation
Carbon monoxide (CO) consists of one carbon and one oxygen atom per molecule. To find the number of carbon atoms, calculate the moles of CO from the given mass and use Avogadro’s number to convert to atoms. Similarly, to find the mass of oxygen in a specific number of CO molecules, convert molecules to moles, recognize that there is one oxygen atom per molecule, and then calculate the mass using the molar mass of oxygen.
