The molecular formula of disulfur dioxide is S2O2. What is the empirical formula of disulfur dioxide? Question 2 In Lab #7, you collected these values: mass of crucible 21.3456 g mass of crucible plus copper wire = 21.4409 g mass of crucible plus copper sulfide = 21.4649 g Calculate the moles of copper (round your answer to five decimal places) 0.00150 0.01550 0.00220 0.00110
The Correct Answer and Explanation is:
Question 1: Empirical Formula of Disulfur Dioxide (S₂O₂)
The molecular formula of disulfur dioxide is given as S₂O₂. To find the empirical formula, we need to reduce the subscripts in the molecular formula to their simplest whole-number ratio.
- The molecular formula is S₂O₂, meaning there are 2 sulfur atoms and 2 oxygen atoms.
- To simplify the ratio, divide both the number of sulfur atoms and the number of oxygen atoms by their greatest common divisor, which is 2.
So, dividing both subscripts by 2:
- S₂ → S₁
- O₂ → O₁
Thus, the empirical formula of disulfur dioxide is SO.
Question 2: Moles of Copper Calculation
The masses collected in the experiment are as follows:
- Mass of the crucible = 21.3456 g
- Mass of the crucible + copper wire = 21.4409 g
- Mass of the crucible + copper sulfide = 21.4649 g
Step 1: Calculate the mass of copper wire and copper sulfide
- Mass of copper wire = Mass of the crucible + copper wire – Mass of the crucible
- 21.4409 g – 21.3456 g = 0.0953 g
- Mass of copper sulfide = Mass of the crucible + copper sulfide – Mass of the crucible
- 21.4649 g – 21.3456 g = 0.1193 g
Step 2: Calculate the mass of copper (Cu)
- The difference between the mass of copper wire and the mass of copper sulfide gives the mass of sulfur that reacted with copper:
- Mass of sulfur = 0.1193 g – 0.0953 g = 0.0240 g
Since copper sulfide (CuS) consists of copper (Cu) and sulfur (S), we know that the mass of copper remains constant, and sulfur reacts with it to form copper sulfide.
Step 3: Find the moles of copper
- The molar mass of copper (Cu) is 63.55 g/mol.
- Using the mass of copper wire (which is the mass of copper before reaction):
- Moles of copper = Mass of copper / Molar mass of copper
- Moles of copper = 0.0953 g / 63.55 g/mol
- Moles of copper = 0.00150 mol
Thus, the number of moles of copper is 0.00150 mol, and the correct answer is 0.00150.
Explanation:
- For the empirical formula, the goal is to simplify the molecular formula to its lowest ratio. The ratio of sulfur to oxygen atoms is 2:2, so we divide both by 2 to get the empirical formula SO.
- In the second question, the key step was to determine the mass of copper, then convert it to moles using the molar mass of copper (63.55 g/mol). The calculated moles of copper were 0.00150 mol, which corresponds to the given options.
