Final answer:
To make 25 ml of a 1.4M NaCl solution, you would need 2.0454 grams of NaCl, calculated by first determining the number of moles required and then converting those moles to grams using the molar mass of NaCl.
Step-by-step explanation:
To calculate the mass of NaCl needed to make a 25 ml of a 1.4M solution, we can use the formula:
Molarity (M) = moles of solute / liters of solution
Firstly, convert 25 mL to liters, because molarity is expressed in moles per liter. Thus:
25 mL = 0.025 L
Then, calculate the moles of NaCl needed using the molarity:
Moles of NaCl = Molarity × Volume in liters
Moles of NaCl = 1.4 M × 0.025 L = 0.035 moles
Next, convert moles to grams using the molar mass of NaCl:
molar mass of sodium chloride (NaCl) = 58.44 g/mol
Mass in grams = Moles × Molar Mass
Mass in grams = 0.035 moles × 58.44 g/mol
Mass in grams = 2.0454 grams
Therefore, you would need 2.0454 grams of NaCl to make 25 ml of a 1.4M solution.