1 Answer. SCooke · Stefan V. 1.2×1023 molecules. Hope this helps
Answer:
II) Objects made of silver become tarnished.
Explanation:
Physical properties are the properties which can be observed without changing identity of substance.
Chemical properties are the properties which describe how the substance changes into the different substance completely.
Boiling is an example of physical change in state of the substance. Color is also an example of physical property like boiling point and hence these are constants. The reason of the color is that the chromium ions shows certain colors as the electrons are excited due to absorption of the light. The tarnishing of the silver is an example of the chemical change which occurs due to the reaction of the silver with oxygen. This is also known as corrosion.

<h3><u>Basic </u><u>Characteristic </u><u>of </u><u>acids </u></h3>
- Acids are sour in taste
- Acid turns blue litmus paper or solution into red litmus paper or solution
- Acids are good conductor of electricity because it dissociate into cation in aqueous solution
- Acids classified into edible acids and non edible acids. Non edible acids are very hazardous
- Generally, All acids are soluble in water
- Acids have PH smaller than 7
<u>Arrhenius </u><u>definition </u><u>of </u><u>acids </u><u>:</u><u>-</u>
According to Arrehinus,
- Acids are those substances which when dissolve in water given H positive ions . Then, this hydrogen ions combine with water to form H30 + ions
<u>Second </u><u>definition </u><u>of </u><u>Acids </u><u>was </u><u>given </u><u>by </u><u>Bonsted </u><u>Lowry </u><u>:</u><u>-</u>
According to Bonsted Lowry
- Acids are the proton donors that is when acids dissociate into water gives hydrogen ions that is H+ ions
<u>3rd </u><u>definition </u><u>was </u><u>given </u><u>by </u><u>Lewis </u>
According to Lewis
- Acids are those substances which have the ability to accept a pair of electrons .
Example of Acids
- HNO3 :- Nitric acid
- H2SO4 :- Sulfuric acid
- HCl :- Hydrochloric acid
<h3><u>Basic </u><u>characterists </u><u>of </u><u>bases </u></h3>
- Bases are bitter in taste
- Bases turns red litmus paper into blue litmus paper or solution
- Bases are also good conductor of electricity because on dissociation it produces anion in aqueous solution
- Bases are also good conductor of electricity
- When bases are soluble in water then they are known as alkaline base
- Bases have PH greater than 7
<u>Arrehinus definition of bases :-</u>
According to Arrehinus ,
- Bases are those substances which when dissolve in water produce OH negative ions that is hydroxide ions
<u>Bonsted Lowry definition </u>
According to Bonsted Lowry
- Bases are the proton donors as they produce OH negative ions in dissociation in aqueous solution
<u>Lewis </u><u>definition </u>
According to Lewis
- Acids are those substances which have the ability to lose electrons that is they are electron donors.
Example of bases
- Ca(OH)2 :- Calcium hydroxide
- NaOH :- Sodium hydroxide
- KOH :- Potassium hydroxide
[ Note :- There are so many Lewis acids and bases but they are not Arrhenius or Lowry acids or bases ]
<h3><u>Basic </u><u>characteristic </u><u>of </u><u>salt </u></h3>
- Salts are the ionic compounds which are composed of acids and bases that cation and anion
- Salts are generally found in oceans and seas in the forms of crystals
- As they are composed of acids and bases so they are neutral in nature but the salt of strong acid or weak base is acidic in nature or vice versa
- Salts are also good conductor of electricity as they form ionic bond
- Generally, All salts are soluble in water.
- The PH of common Salt is 7
Example of salts
- NH4Cl :- Ammonium chloride
- CuSO4 :- Copper sulphate
- NaCl :- Sodium chloride
Answer:
frequency = 0.47×10⁴ Hz
Explanation:
Given data:
Wavelength of wave = 6.4× 10⁴ m
Frequency of wave = ?
Solution:
Formula:
Speed of wave = wavelength × frequency
Speed of wave = 3 × 10⁸ m/s
Now we will put the values in formula.
3 × 10⁸ m/s = 6.4× 10⁴ m × frequency
frequency = 3 × 10⁸ m/s / 6.4× 10⁴ m
frequency = 0.47×10⁴ /s
s⁻¹ = Hz
frequency = 0.47×10⁴ Hz
Thus the wave with wavelength of 6.4× 10⁴ m have 0.47×10⁴ Hz frequency.
A part of organism that is typically self contained and have a specific vital