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Calculate the mass of sodium hydroxide in 30.0cm cubed of a 0.105 mol/dm cubed solution

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To find the mass of sodium hydroxide in a solution, multiply the volume of the solution by its concentration to get the number of moles, and then multiply by the molar mass of NaOH. The mass of NaOH in a 30.0 cm³ solution with a concentration of 0.105 mol/dm³ is 0.126 grams.

The mass of sodium hydroxide (NaOH) in 30.0 cm³ of a 0.105 mol/dm³ solution can be calculated using the formula: mass = number of moles × molar mass. To find the number of moles of NaOH, we use the volume of the solution and its concentration. Since the volume needs to be in dm³, we convert 30.0 cm³ to 0.030 dm³ by dividing by 1000 (because 1 dm³ = 1000 cm³). Then we use the concentration of the solution (0.105 mol/dm³) to find the moles of NaOH.

Number of moles = volume × concentration = 0.030 dm³ × 0.105 mol/dm³ = 0.00315 mol of NaOH

Next, we calculate the molar mass of NaOH using the atomic masses of its constituent elements. According to the periodic table:

  • Na = 22.990 g/mol
  • O = 15.999 g/mol
  • H = 1.008 g/mol

Molar mass of NaOH = 22.990 g/mol Na + 15.999 g/mol O + 1.008 g/mol H = 39.997 g/mol

Finally, we find the mass using the molar mass:

Mass of NaOH = number of moles × molar mass = 0.00315 mol × 39.997 g/mol = 0.126 g

30.0 cm³ of a 0.105 mol/dm³ sodium hydroxide solution contains 0.126 grams of NaOH.

User Gabriel M
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mol of NAOH = C × V

= 0.105 mol/dm-³ × 30 × 10-³dm³

= 3.15 × 10-³ mol

mass of NaOH = M × n

= 40gmol-¹ × 3.15 ×10-³ mol

= 126 × 10-³ mol

= 0.126 mol

User Elias Bachaalany
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6.4k points