Answer:
Democritus
Explanation:
Democritus was a Greek philosopher that first conceptualize the idea of an atom. He suggested matter to be composed of atoms, which move through empty spaces. Democritus explained that different kinds of atoms have different sizes and shapes.
His proposition was not made into a theory by the scientific community of that time because there was barely little to no evidence to support the findings. The technology as a that time were not sophisticated to back up these claims.
I think that should be evaporation :)
Answer:
- <u>2.59 × 10⁻⁷ m = 259 nm</u>
Explanation:
You need to calculate the wavelength of a photon with an energy equal to 463 kJ/mol, which is the energy to break an oxygen-hydrogen atom.
The energy of a photon and its wavelength are related by the Planck - Einstein equation:
Where:
- h = Planck constant (6.626 × 10⁻³⁴ J . s) and
- ν = frequency of the photon.
And:
Where:
- c = speed of light (3.00 × 10⁸ m/s in vacuum)
- λ = wavelength of the photon
Thus, you can derive:
Solve for λ:
Before substituting the values, convert the energy, 463 kJ/ mol, to J/bond
- 463 kJ/ mol × 1,000 J/kJ × 1 mol / 6.022 × 10 ²³ atom × 1 bond / atom
= 7.69×10²³ J / bond
Substitute the values and use the energy of one bond:
- λ = 6.626 × 10⁻³⁴ J . s × 3.00 × 10⁸ m/s / 7.69×10²³ J = 2.59 × 10⁻⁷ m
The wavelength of light is usually shown in nanometers:
- 2.59 × 10⁻⁷ m × 10⁹ nm / m = 259 nm ← answer
Molar mass Na2SO4 = <span>142.04 g/mol
142.04 g -------------- 6.02x10</span>²³ atoms
?? g ------------------ 7.4x10²³ atoms
142.04 x ( 7.4x10²³) / 6.02x10²³
=> 174.60 g