Question

A student measures out 45.62 g of sodium chloride on a laboratory scale. How many moles of sodium chloride have they weighed? Your answer should have the appropriate number of significant figures (use two decimal places in atomic masses). Only give the numeric value of your answer. Don't include the units.

Answer 1

The student measured 45.62 g of sodium chloride which equals 0.78 moles of NaCl, calculated using the molar mass of NaCl, 58.44 g/mol.

Step-by-step explanation:

To calculate the moles of sodium chloride (NaCl) from its mass, we use the molar mass of NaCl as a conversion factor. The molecular weight or molar mass of NaCl is the sum of the atomic masses of sodium (Na) and chlorine (Cl). The molar mass is found to be 58.44 g/mol where the atomic mass of Na is 22.99 g/mol and Cl is 35.45 g/mol. Given that a student has measured out 45.62 g of NaCl, the conversion is done as follows:

Moles of NaCl = weight of NaCl / molar mass of NaCl

Moles of NaCl = 45.62 g / 58.44 g/mol = 0.78

Therefore, the number of moles of sodium chloride weighed by the student is 0.78 mol.