Answer: He theorized that all material bodies are made up of indivisibly small “atoms.” Aristotle famously rejected atomism in On Generation and Corruption. Aristotle refused to believe that the whole of reality is reducible to a system of atoms.
Explanation:
Hydrofluoric acid is not a strong acid despite being a hydrohaulic acid (hydrogen and a halogen). HF is highly corrosive and can be used to dissolve most oxides
Explanation:
The compound disilicon tetraoxide has the formula;
Si₂O₄;
This compound is held together by a polar covalent bond. A polar covalent bond occurs between two species that shares electrons. In this bond type, the more electronegative element draws the shared electrons more closer to itself.
- Oxygen is more electronegative than silicon.
- It will draw the shared electrons more closer.
- This leaves a partial positive charge on the silicon and a negative charge on the oxygen.
Answer:The isoelctric point of phenylalanine is 5.91. Kindly refer the attachment for structure.
Explanation:
Isoeectronic point is the pH at which the amino acid do not migrate in presence of an electric field.Hence at isoelectric point the molecule exists as a neutral molecule.
So for a molecule to not migrate in electric field it must be neutral. At isoelectric point the net charge on the amino acid molecule is zero.
The amino acid at isoelectric point exists as a zwitter ion which has a equal positive and equal negative charge making the net charge of the amino acid to be zero.
since the amino acid molecule has two kinds of functional group present which are an amine group and a carboxylic acid group.
So to calculate the isoelectric point we must know the pKa of these functional groups.
The formula for calculating the isoelectic point (pI) is :
![pI=[pKa1+pKa2]\times 1/2](https://tex.z-dn.net/?f=pI%3D%5BpKa1%2BpKa2%5D%5Ctimes%201%2F2)
pI=Isoelectric point
pKa1=pKa of carboxy group
pKa2=pKa of amine group
we have the pKa1 and pKa2 given in the question so putting these values in above formula we can calculate the isoelectric point.
pKa1=2.58
pKa2=9.24
pI=1/2×[pKa1+pKa2]
pI=1/2×[2.58+9.24]
pI=5.91
The isoelectric point is 5.91 hence at a pH of 5.91 phenylalanine would exist as a zwitterion and would not migrate in presence of a electric field.
Answer:
D) With an increase in altitude, atmospheric pressure increases as well.
Explanation:
Generally when altitude increases, the value of pressure decreases. This shows that pressure is inversely proportional to altitude. For example, the higher the altitude, the lower the pressure and vice versa. At very high altitude, the number of molecules of air are smaller than the number of moles of air at very low altitude. Thus, the higher the altitude, the lower the atmospheric pressure and the lower the altitude, the higher the atmospheric pressure. Therefore, option (D) is false.