"The mass density of brain matter is 1.040 g/cm^3, and of that, the mass fraction which is hydrogen, is 0.107. Find the number of hydrogen protons in a volume of 1cm^3 of brain tissue"
To find the number of hydrogen protons in a volume of 1 cm^3 of brain tissue, we will need to make a few calculations based on the given information.
First, we need to calculate the mass of 1 cm^3 of brain tissue. The mass density of brain matter is given as 1.040 g/cm^3. Therefore, the mass of brain tissue in 1 cm^3 is:
Mass = Density * Volume
Mass = 1.040 g/cm^3 * 1 cm^3
Mass = 1.040 g
Next, we will determine the mass of hydrogen in 1 cm^3 of brain tissue. The mass fraction of hydrogen is given as 0.107. Therefore, the mass of hydrogen in 1 cm^3 of brain tissue is:
Mass of Hydrogen = Mass of Brain Tissue * Mass Fraction of Hydrogen
Mass of Hydrogen = 1.040 g * 0.107
Mass of Hydrogen = 0.11128 g
Now, to find the number of hydrogen protons, we need to convert the mass of hydrogen to moles. The molar mass of hydrogen (H) is 1.0078 g/mol. Therefore, the number of moles of hydrogen is:
Number of Moles = Mass of Hydrogen / Molar Mass of Hydrogen
Number of Moles = 0.11128 g / 1.0078 g/mol
Number of Moles = 0.11026 mol
Finally, we can calculate the number of hydrogen protons in 1 cm^3 of brain tissue. Since each hydrogen atom has one proton, the number of protons is equal to the number of moles:
Number of Hydrogen Protons = Number of Moles of Hydrogen
Number of Hydrogen Protons = 0.11026 mol
Therefore, the number of hydrogen protons in 1 cm^3 of brain tissue is approximately 0.11026 mol.