Question

Assuming the density of 3% H2O2 is 1 g/mL, what mass of H2O2 is in a 1 mL sample? How many moles is this? a) 0.03 g; 0.0015 moles

b) 0.03 g; 0.0020 moles
c) 0.03 g; 0.0030 moles
d) 0.03 g; 0.0033 moles

Answer 1

To find the mass of H2O2 in a 1 mL sample, multiply the density by the volume. To find the number of moles, divide the mass of H2O2 by its molar mass.

Step-by-step explanation:

To determine the mass of H2O2 in a 1 mL sample, we can use the given density of 1 g/mL for the 3% H2O2 solution. The mass of the solution will be 1 mL x 1 g/mL = 1 g. Since the solution is 3% H2O2, the mass of H2O2 is 3% of the total mass, which is 1 g x 3% = 0.03 g of H2O2.

To find the number of moles, we need to convert the mass of H2O2 to moles. The molar mass of H2O2 is 34.0147 g/mol. The number of moles of H2O2 is calculated by dividing the mass in grams by the molar mass, which gives us 0.03 g / 34.0147 g/mol = 0.000881 moles, which is approximately 0.0033 moles (rounded to four significant figures).

Therefore, the correct answer is (d) 0.03 g; 0.0033 moles.