Question

Danny weighs 4.9699 g of NaCl on a balance in a chemistry lab. How many moles of this compound did he weigh? Recall: moles = mass/molar mass.

Option A: 0.1 moles
Option B: 0.2 moles
Option C: 0.3 moles
Option D: 0.4 moles

Answer 1

Danny weighed 4.9699 g of NaCl, which when divided by the molar mass of NaCl (58.44 g/mol), equals approximately 0.085 moles. This value is closest to 0.1 moles.

Step-by-step explanation:

To determine how many moles of NaCl Danny weighed, we follow these steps:

Convert from grams to moles of NaCl using the molar mass of NaCl as the unit conversion factor. The molar mass of NaCl is 58.44 g/mol. So, we divide Danny's measured mass of 4.9699 g by this molar mass:

4.9699 g ÷ 58.44 g/mol = 0.085 moles NaCl
After calculating this, we see that the number of moles he weighed is closest to Option B: 0.1 moles, which is the correct answer.

To calculate the number of moles of NaCl, we can use the formula: moles = mass/molar mass. Given that Danny weighs 4.9699 g of NaCl, and the molar mass of NaCl is 58.44 g/mol, we can calculate:

moles = 4.9699 g / 58.44 g/mol = 0.085 moles

So, Danny weighed approximately 0.085 moles of NaCl.