Answer:
0.0845 M
Explanation:
First we <u>convert 4.27 grams of potassium iodide into moles</u>, using its <em>molar mass</em>:
- Molar Mass of KI = 166 g/mol
- 4.27 g ÷ 166 g/mol = 0.0257 mol
Now we <u>calculate the molarity of the solution</u>, using <em>the number of moles and the given volume</em>:
- Molarity = moles / liters
- Molarity = 0.0257 mol / 0.304 L = 0.0845 M
The softest mineral in the Mohs Hardness Scale is talc.
Talc is often used in baby powder and corn starch, among other things. Talc cleaves into thin sheets, and it is held together only by van de Waals bonds, which allows these sheets to slip past each other. This gives the mineral its softness and it is often valued as a high-temperature lubricant.
Answer:
Option C = electron
Explanation:
Electrons are responsible for the production of colored light.
Electron:
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol= e-
Mass= 9.10938356×10⁻³¹ Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.
How electrons produce the colored light:
Excitation:
When the energy is provided to the atom the electrons by absorbing the energy jump to the higher energy levels. This process is called excitation. The amount of energy absorbed by the electron is exactly equal to the energy difference of orbits.
De-excitation:
When the excited electron fall back to the lower energy levels the energy is released in the form of radiations. this energy is exactly equal to the energy difference between the orbits. The characteristics bright colors are due to the these emitted radiations. These emitted radiations can be seen if they are fall in the visible region of spectrum.
Other process may involve,
Fluorescence:
In fluorescence the energy is absorbed by the electron having shorter wavelength and high energy usually of U.V region. The process of absorbing the light occur in a very short period of time i.e. 10 ∧-15 sec. During the fluorescence the spin of electron not changed.
The electron is then de-excited by emitting the light in visible and IR region. This process of de-excitation occur in a time period of 10∧-9 sec.
Phosphorescence:
In phosphorescence the electron also goes to the excitation to the higher level by absorbing the U.V radiations. In case of Phosphorescence the transition back to the lower energy level occur very slowly and the spin pf electron also change.
Answer:
A) Separating funnel method
B) Simple Distillation
C) Evaporation
D) Sublimation
E) It is based on the principle of separation whereby even though two substances are dissolved in the same solvent, their respective solubilities could be different. Thus, the component that has more solubility will rise fastest and will therefore get separated from the mixture.
Explanation:
A)
B) Kerosene and petrol are both miscible liquids and the difference in their boiling point temperature is not more than 25°C. Thus, we make use of Simple distillation.
C) Can be separated by evaporation where the water is boiled and it evaporates and leaves the salt behind
D) To separate camphor from salt, we use sublimation so the camphor can change directly from solid to the gas state without passing through the liquid state.
E) Chromatography is used to separate components of a mixture.
It is based on the principle of separation whereby even though two substances are dissolved in the same solvent, their respective solubilities could be different. Thus, the component that has more solubility will rise fastest and will therefore get separated from the mixture.
Yes, it is true that ions can have a positive or negative charge.
