Answer:
![\frac{[magenta\ phenolphthalein]}{[colorless\ phenolphthalein]}=31.62](https://tex.z-dn.net/?f=%5Cfrac%7B%5Bmagenta%5C%20phenolphthalein%5D%7D%7B%5Bcolorless%5C%20phenolphthalein%5D%7D%3D31.62)
Explanation:
Considering the Henderson- Hasselbalch equation for the calculation of the pH of the buffer solution as:
![pH=pKa+\log\frac{[base]}{[acid]}](https://tex.z-dn.net/?f=pH%3DpKa%2B%5Clog%5Cfrac%7B%5Bbase%5D%7D%7B%5Bacid%5D%7D)
Where Ka is the dissociation constant of the acid.
pKa of phenolphthalein = 9.40
pH = 10.9
So,
![10.9=9.40+\log\frac{[magenta\ phenolphthalein]}{[colorless\ phenolphthalein]}](https://tex.z-dn.net/?f=10.9%3D9.40%2B%5Clog%5Cfrac%7B%5Bmagenta%5C%20phenolphthalein%5D%7D%7B%5Bcolorless%5C%20phenolphthalein%5D%7D)
c)pattern
Explanation:
A general change such as increasing or decreasing numbers is called a pattern. A pattern shows a structured way of implementing a change.
- Patterns can be a form of increment in values by adding a particular number at intervals.
- It can be a division, multiplication or subtraction of a consistent number.
- Patterns can provide insight into understanding a number system or a group of numbers.
- Sequences are usually derived from patterns.
Learn more:
Patterns brainly.com/question/4694425
#learnwithBrainly
A substance that undergoes change during a reaction, usually from coming in contact with another substance
Answer:
(i) Bohr; (ii) de Broglie; (iii) Heisenberg (v) Schrödinger
Explanation:
(i) Niels Bohr — 1913 — proposed that electrons travel in fixed orbits with <em>quantized energy levels</em> and that they jump from one energy level to another by absorbing or emitting quanta of light.
(ii) <em>Louis de Broglie</em> — 1924 — proposed the wave nature of electrons and suggested that all matter behaves as both waves and particles (<em>wave-particle duality</em>).
(iii) Werner Heisenberg — 1927 — formulated quantum mechanics in terms of matrices and proposed his famous <em>uncertainty principle</em>.
(v) Erwin Schrödinger — 1926 — applied wave mechanics to the electron in a hydrogen atom, showing that electrons exist in <em>orbitals </em>rather that orbits.
(iv) <em>Ernest Rutherford</em> — 1911 — proposed that atoms have most of their mass in a central nucleus (<em>nuclear atom</em>). Quantum mechanics had not yet been invented.
