14. What is the number of moles in 42 g of NaCl?
A. 1.8 mol NaCl
B. 0.72 mol NaCl
C. 0.61 mol NaCl
D. 1.2 mol NaCl
I'm sorry, I have no idea what I'm doing here.
mols = grams/molar mass
b. 0.72 mole naci
No worries! I can help you with that. To determine the number of moles in a given amount of a substance, you need to use its molar mass.
The molar mass of NaCl (sodium chloride) can be calculated by adding up the atomic masses of sodium (Na) and chloride (Cl) in the compound. The atomic mass of sodium is 22.99 g/mol, and the atomic mass of chlorine is 35.45 g/mol. Adding these two values gives us a molar mass of NaCl equal to 58.44 g/mol.
To find the number of moles in 42 g of NaCl, you divide the given mass by the molar mass. So, 42 g NaCl / 58.44 g/mol = 0.72 mol NaCl.
Therefore, the answer is B. 0.72 mol NaCl.