A chemistry student must write down in her lab notebook the concentration of a solution of sodium hydroxide the concentration of a solution equals the mass of what’s dissolved divided by the total volume of solution
The label on the graduated cylinder says empty weight 1.500g
She put some solid sodium hydroxide into the graduated cylinder and weighed it with the sodium hydroxide added the cylinder weighted 10.98g
She added water to the graduated cylinder and dissolved the sodium hydroxide completely then she read the total volume of solution from the markings on the graduated cylinder the total volume of the solution was 138.61mL
What concentration should the student write down in her lab notebook be sure your answer has the correct number of significant digits
To find the concentration of the sodium hydroxide solution, we need to calculate the mass of the sodium hydroxide dissolved in the solution and divide it by the total volume of the solution.
First, we calculate the mass of sodium hydroxide dissolved in the solution:
Mass of sodium hydroxide = Weight of graduated cylinder with sodium hydroxide - Empty weight of graduated cylinder
Mass of sodium hydroxide = 10.98g - 1.500g = 9.48g
Next, we calculate the concentration:
Concentration = Mass of sodium hydroxide / Total volume of solution
Concentration = 9.48g / 138.61mL
The concentration should be written as:
Concentration = 0.0683 g/mL
To find the concentration, we need to determine the mass of sodium hydroxide dissolved and the total volume of the solution.
Given information:
Empty weight of graduated cylinder = 1.500g
Weight of graduated cylinder + sodium hydroxide = 10.98g
Total volume of solution = 138.61 mL
Step 1: Calculate the mass of sodium hydroxide
Mass of sodium hydroxide = Weight of graduated cylinder + sodium hydroxide - Empty weight of graduated cylinder
Mass of sodium hydroxide = 10.98g - 1.500g
Mass of sodium hydroxide = 9.48g
Step 2: Calculate the concentration of the solution
Concentration (in g/mL) = Mass of sodium hydroxide / Total volume of solution
Concentration = 9.48g / 138.61mL
Since the question asks for the concentration with the correct number of significant digits, we need to use the same number of significant digits as the given data, which is 3 significant digits.
Concentration = 9.48g / 138.61mL
Concentration ≈ 0.068 g/mL (rounded to 3 significant digits)
The student should write down the concentration as approximately 0.068 g/mL in her lab notebook.