The chemical formula for cesium chloride is CsCl. A chemist measured the amount of cesium chloride produced during an experiment. She finds that 90.0 g of cesium chloride is produced. Calculate the number of moles of cesium chloride produced. Be sure your answer has the correct number of significant digits.
The Correct Answer and Explanation is:
Correct Answer:
The number of moles of cesium chloride (CsCl) produced is 0.532 mol.
Step-by-step Explanation
To calculate the number of moles of a substance from its mass, we use the formula: moles=mass (g)molar mass (g/mol)\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}moles=molar mass (g/mol)mass (g)
First, we need the molar mass of cesium chloride (CsCl). The molar mass is found by adding the atomic masses of cesium (Cs) and chlorine (Cl).
- Atomic mass of cesium (Cs) ≈ 132.91 g/mol
- Atomic mass of chlorine (Cl) ≈ 35.45 g/mol
Molar mass of CsCl=132.91+35.45=168.36 g/mol\text{Molar mass of CsCl} = 132.91 + 35.45 = 168.36 \text{ g/mol}Molar mass of CsCl=132.91+35.45=168.36 g/mol
Next, we use the given mass of cesium chloride: Mass=90.0 g\text{Mass} = 90.0 \text{ g}Mass=90.0 g
Now apply the formula for moles: moles of CsCl=90.0 g168.36 g/mol≈0.5346\text{moles of CsCl} = \frac{90.0 \text{ g}}{168.36 \text{ g/mol}} \approx 0.5346moles of CsCl=168.36 g/mol90.0 g≈0.5346
Rounded to three significant figures (to match the given mass of 90.0 g), the final answer is: Moles of CsCl=0.535 mol\text{Moles of CsCl} = 0.535 \text{ mol}Moles of CsCl=0.535 mol
However, since the original question asked for the number of moles based on 90.0 g, and significant figures are crucial in chemistry, we keep three significant digits. Therefore: Final Answer: 0.535 mol\textbf{Final Answer: 0.535 mol}Final Answer: 0.535 mol
This calculation helps chemists determine how many particles, atoms, or molecules are involved in a chemical reaction. The mole is a bridge between the atomic scale and the macroscopic scale, enabling measurements in the lab to correspond to the number of particles reacting. In this case, 0.535 moles of CsCl means that approximately 0.535×6.022×10230.535 \times 6.022 \times 10^{23}0.535×6.022×1023 formula units of CsCl were produced in the experiment.
