4.0 g of sodium hydroxide in 250 cm3 of solution contains?

To determine the moles of sodium hydroxide in the solution, we need to use the formula: moles = mass / molar mass The molar mass of sodium hydroxide (NaOH) is approximately 40 g/mol (23 g/mol for Na + 17 g/mol for OH). First, we need to convert the volume of the solution from cm^3 to dm^3: 250 cm^3 = 0.25 dm^3 Then, we can calculate the concentration of the solution in moles per dm^3: concentration = (4.0 g / 40 g/mol) / 0.25 dm^3 = 0.4 mol/dm^3 Therefore, the answer is: - 0.40 moles per dm^3 So, the correct label for this question would be: "concentration"