Final answer:
To find the number of moles in 127.5 grams of Sodium Chloride, use the molar mass of NaCl (58.44 g/mol) in the calculation. This results in 2.18 moles of NaCl.
Step-by-step explanation:
To determine how many moles of Sodium Chloride (NaCl) are present in 127.5 grams, you first need to calculate the molar mass of NaCl. The molar mass is found by summing the atomic masses of sodium (Na) and chlorine (Cl), which equals 22.99 amu for Na and 35.45 amu for Cl. Therefore, the molar mass of NaCl is 58.44 grams/mole.
Next, you convert grams to moles using this molar mass:
127.5 grams NaCl × (1 mole NaCl / 58.44 grams NaCl) = 2.18 moles NaCl (rounded to two decimal places).
The student's calculation step (resulting in 0.072 mol NaCl) seems to be in error or refers to a different mass of NaCl. To answer the student’s question directly: 127.5 grams of NaCl is equivalent to 2.18 moles of NaCl.
To find the number of moles in 127.5 grams of Sodium Chloride (NaCl), you can use the formula:
Number of moles = Mass / Molar mass
The molar mass of NaCl is 58.44 grams/mole. So, the number of moles of NaCl in 127.5 grams is:
Number of moles = 127.5 grams / 58.44 grams/mole = 2.185 moles (rounded to three decimal places)