Answer:
1.98x10⁻¹² kg
Explanation:
The <em>energy of a photon</em> is given by:
h is Planck's constant, 6.626x10⁻³⁴ J·s
c is the speed of light, 3x10⁸ m/s
and λ is the wavelenght, 671 nm (or 6.71x10⁻⁷m)
- E = 6.626x10⁻³⁴ J·s * 3x10⁸ m/s ÷ 6.71x10⁻⁷m = 2.96x10⁻¹⁹ J
Now we multiply that value by <em>Avogadro's number</em>, to <u>calculate the energy of 1 mol of such protons</u>:
- 1 mol = 6.023x10²³ photons
- 2.96x10⁻¹⁹ J * 6.023x10²³ = 1.78x10⁵ J
Finally we <u>calculate the mass equivalence</u> using the equation:
- m = 1.78x10⁵ J / (3x10⁸ m/s)² = 1.98x10⁻¹² kg
I will present a simple reaction so we can do this conversion:
2H₂ + O₂ → 2H₂O
We will assume we have 32 g of O₂ and we want to find the amount of water, assuming this reaction goes to completion. We must first convert the initial mass to moles, which we do using the molar mass in units of g/mol. The molar mass of O₂ is 32 g/mol.
32 g O₂ ÷ 32 g/mol = 1 mole O₂.
Now that we have moles of oxygen, we use the molar coefficients to find the ratio of water molecules to oxygen molecules. We can see there are 2 moles of water for every 1 mole of oxygen.
1 moles O₂ x (2 mol H₂O/ 1 mol O₂) = 2 moles H₂O
Now that we have the moles of water, we can convert this amount into grams using the molar mass of water, which is 18 g/mol.
2 moles H₂O x 18 g/mol = 36 g H₂O
Now we have successfully converted the mass of one molecule to the mass of another.
Answer:
Solute - The solute is the substance that is being dissolved by another substance. In the example above, the salt is the solute. Solvent - The solvent is the substance that dissolves the other substance.
Explanation:
Answer: m-%(Ca) = 40.08 / 110.98
Explanation: molar mass of CaCl2 is 40.08+ 2·35.45 = 110.98
Think you have one mole substance. It contains 40.08 g Ca
Because you are never 100% precise during the work, so it's best and most accurate answer is always the average of more trials. basically the more you do, the more accurate the answer shall be
