Chemistry Stoichiometric Relationship

Question

Q5. How many grams of NaCl are contained in a 250 cm³ of a solution with concentration 0.4 mol/dm³?

Answer 1

1. To solve this problem, we can use the formula:
2. number of moles = concentration x volume
3. First, we need to convert the volume of the solution from cubic centimeters (cm3) to decimeters cubed (dm3) since the concentration is given in units of mol/dm3:
4. 250 cm3 = 0.25 dm3
5. Next, we can calculate the number of moles of NaCl in the solution:
6. number of moles = concentration x volume number of moles = 0.4 mol/dm3 x 0.25 dm3 number of moles = 0.1 moles
7. Finally, we can convert the number of moles to grams using the molar mass of NaCl:
8. mass = number of moles x molar mass mass = 0.1 moles x 58.44 g/mol (molar mass of NaCl) mass = 5.844 grams
9. Therefore, there are 5.844 grams of NaCl in a 250 cm3 solution with a concentration of 0.4 mol/dm3.