Answer:
The experimental discoveries that led Niels Bohr to propose an improved model of the atom were the line spectrum or emission spectrum of hydrogen and the photoelectric effect.
Explanation:
There are several types of electromagnetic radiation. Going from long-wavelength, low-frequency radio waves to short-wavelength, high-frequency gamma rays. This range of frequencies and wavelengths is known as the electromagnetic spectrum. Only a small part of this spectrum can be seen with the naked eye. Thus it is called the visible region of the spectrum.
If the white light is passed through a glass prism, it is possible to see that visible region as a "rainbow" of colors. But if we use a hydrogen lamp instead of an ordinary white light lamp, a discontinuous spectrum will appear. This is a group of narrow colored lines separated by dark regions. Each line corresponds to electromagnetic radiation of a specific frequency and wavelength. This emission spectrum or line spectrum is characteristic of hydrogen and, therefore, can be used to identify it.
On the other hand, Albert Einstein used the Planck's Quantum theory to explain the photoelectric effect, which consists of a beam of electrons produced when a beam of light collides with certain surfaces. This effect could not be explained by classical physics.
Einstein said that the electromagnetic radiation is quantized; it means that light and all the other electromagnetic radiations are made of little packets of energy, known as photons.
Niels Bohr tried to combine ideas from classical physics and the quantum theory to explain the line spectrum of hydrogen atom and its structure. That was the moment when he realized that electrons could not have chaotic movement around the nucleus but with specified energy values or energy levels.
Answer:
i only found the 49, hope it still helps, mate
49. In this question (t½) of C-14 is 5730 years, which means that after 5730 years half of the sample would have decayed and half would be left as it is.
After 5730 years ( first half life) 70 /2 = 35 mg decays and 35 g remains left.
After another 5730 years ( two half lives or 11460 years) 35 /2 = 17.5mg decays and 17.5 g remains left .
After another 5730 years ( three half lives or 17190 years) 17.5 /2 = 8.75mg decays and 8.75g remains left.
after three half lives or 17190 years, 8.75 g of C-14 will be left.
The hemisphere tilted most toward our home star sees its longest day, while the hemisphere tilted away from the sun sees its longest night. During the Northern Hemisphere's summer solstice—which always falls around June 21—the Southern Hemisphere gets its winter solstice.
Hello!
When NaOH is added to a buffer composed of CH₃COOH and CH₃COO⁻, the following reactions happen:
-First, the NaOH is neutralized by CH₃COOH:
NaOH + CH₃COOH → H₂O + CH₃COONa
-Second, the CH₃COONa dissociates in its ions:
CH₃COONa → CH₃COO⁻ + Na⁺
-Finally, CH₃COO⁻ (a weak base) reacts with water to form OH⁻ ions and regenerate CH₃COOH
CH₃COO⁻ + H₂O ⇄ CH₃COOH + OH⁻
By this sequence of reactions, the buffer can mitigate the effect of the strong base added.
Have a nice day!
Hydrochloric acid is stronger than carbonic acid; true