Final answer:
To find the number of moles of hydrogen peroxide in 7.50 mL of 100% pure H2O2, assuming a similar density to water, we calculate the mass and divide it by the molar mass of H2O2, yielding approximately 0.2204 moles.
Step-by-step explanation:
To calculate the number of moles of hydrogen peroxide (H2O2) in 7.50 mL of 100% pure H2O2, we first need to know the density of H2O2. Assuming that it is similar to water (approximately 1.0 g/mL due to the lack of provided information on its actual density), the mass of 7.50 mL would be roughly 7.50 g (since 1 mL of water weighs approximately 1 g).
The molar mass of H2O2 is 34.0147 g/mol (2 hydrogen atoms' combined atomic mass is approximately 2.016 g/mol and 2 oxygen atoms' combined atomic mass is approximately 31.998 g/mol). The number of moles is the mass divided by the molar mass, which gives us:
Number of moles = \( \frac{7.50\,\text{g}}{34.0147\,\text{g/mol}} \) = 0.2204 moles
Therefore, you would have approximately 0.2204 moles of H2O2 if you had 7.50 mL of 100% hydrogen peroxide.