Answer :
A. 38.2 g NaCl: 0.654 mol, B. 36.5 g NO: 1.216 mol, C. 4.25 kg CO₂: 96.57 mol, D. 2.71 mg CCl₄: 0.0000176 mol.
The following formula to convert grams (g), kilograms (kg), or milligrams (mg) of a substance to moles (mol):
moles (mol) = mass (g / kg / mg) / molar mass (g/mol)
Molar mass: This is the mass of one mole of a substance and is unique for each compound. You'll likely need a reference table to find the molar masses.
Let's solve for each sample:
A. 38.2 g sodium chloride (NaCl):
Find the molar mass of NaCl (approximately 58.44 g/mol).
Plug in the values: moles (mol) = 38.2 g / 58.44 g/mol = 0.654 mol (rounded to three decimal places)
B. 36.5 g nitrogen monoxide (NO):
Find the molar mass of NO (approximately 30.01 g/mol).
Plug in the values: moles (mol) = 36.5 g / 30.01 g/mol = 1.216 mol (rounded to three decimal places)
C. 4.25 kg carbon dioxide (CO₂):
Convert kilograms (kg) to grams (g): 4.25 kg * 1000 g/kg = 4250 g
Find the molar mass of CO₂ (approximately 44.01 g/mol).
Plug in the values: moles (mol) = 4250 g / 44.01 g/mol = 96.57 mol (rounded to two decimal places)
D. 2.71 mg carbon tetrachloride (CCl₄):
Convert milligrams (mg) to grams (g): 2.71 mg * 1 g/1000 mg = 0.00271 g
Find the molar mass of CCl₄ (approximately 153.82 g/mol).
Plug in the values: moles (mol) = 0.00271 g / 153.82 g/mol = 0.0000176 mol (rounded to six decimal places)
