Calculate the number of coulombs of positive charge in 261 cm3 of (neutral) water. (Hint: A hydrogen atom contains one proton; an oxygen atom contains eight protons.)
261 cm^3 has a mass of 260 g and that is 260/18 = 14.44 moles of H2O. Each mole has 6.02*10^23 molecules, and each molecule has 10 protons.
14.44 x 6.02*10^23 x 10 = __?__ protons
Multiply that by e = 1.60*10^-19 Coulombs per proton for the number of coulombs
To calculate the number of coulombs of positive charge in water, we need to determine the number of protons in the water molecules.
First, let's determine the number of water molecules in 261 cm³ of water.
We know that the density of water is approximately 1 gram/cm³.
Since the molar mass of water (H₂O) is 18 grams/mol, we can calculate the number of moles of water in 261 cm³.
Number of moles of water = (volume of water in cm³) / (molar volume of water)
= 261 cm³ / 18 cm³/mol
≈ 14.5 mol (rounded to one decimal place)
Since each water molecule contains one oxygen atom and two hydrogen atoms, we can calculate the total number of hydrogen and oxygen atoms present:
Number of hydrogen atoms = 2 * (number of moles of water)
≈ 2 * 14.5
≈ 29 (rounded to the nearest whole number)
Number of oxygen atoms = 1 * (number of moles of water)
≈ 1 * 14.5
≈ 14.5 (rounded to one decimal place)
Finally, let's calculate the total number of protons (positive charges) in water:
Number of protons = (number of hydrogen atoms) + (number of oxygen atoms * 8)
= 29 + (14.5 * 8)
= 29 + 116
= 145
So, there are approximately 145 coulombs of positive charge in 261 cm³ of water.
To calculate the number of coulombs of positive charge in the given amount of water, we need to determine the number of protons in the water molecules.
First, let's find the number of water molecules in 261 cm3 of water. We know that 1 cm3 of water is approximately equivalent to 1 gram of water. The molar mass of water (H2O) is approximately 18 grams per mole.
So, using the formula:
number of moles = mass / molar mass,
number of moles of water = 261 g / 18 g/mol ≈ 14.5 moles of water.
Next, we need to find the number of water molecules in 14.5 moles. One mole contains 6.022 × 10^23 molecules (Avogadro's number).
number of molecules = number of moles × Avogadro's number,
number of water molecules = 14.5 moles × (6.022 × 10^23 molecules/mole) ≈ 8.73 × 10^24 water molecules.
Now, for each water molecule, there is one oxygen atom (with 8 protons) and two hydrogen atoms (each with 1 proton).
So, the total number of protons in the water molecules would be:
total number of protons = (number of water molecules × number of protons per molecule),
total number of protons = (8.73 × 10^24 molecules) × [(1 proton/molecule) + (2 protons/molecule)].
total number of protons ≈ 2.62 × 10^25 protons.
Since each proton carries a charge of +1.602 × 10^(-19) coulombs, we can calculate the total positive charge in Coulombs:
total positive charge = (total number of protons) × (charge per proton).
total positive charge ≈ 2.62 × 10^25 protons × (1.602 × 10^(-19) C/proton).
total positive charge ≈ 4.2 × 10^6 Coulombs.
Therefore, the number of coulombs of positive charge in 261 cm3 of water is approximately 4.2 × 10^6 Coulombs.