Answer:
Cl2
Explanation:
Cl2 is a covalent molecule because it contains 2 non-metal elements.
It is non-polar because both elements have the same level of electrostatic attraction (remember that electrostatic attraction is the tendency to steel an electron from an element with lower a lower electrostatic force)
In Cl2 since there are only 2 molecules that are the exact same there is no overall dipole (which means that one end of the molecule is slightly positive or negative charge)
If the molecule replaced one Cl or something else then it would be non-polar since one element will be more electrostatic than the other and one region of the molecule will have a slightly positive or negative charge, unless the molecule is symmetrical like CH4.
For CH4 (methane) if you drew this as a lewis structure the Carbon would be surrounded by 4 hydrogen atoms meaning the overall dipole will be cancelled out since the molecule is symmetrical.
You may not understand the last part but just know that:
If there are 2 of the same atoms in the molecule (Cl2) then it is non-polar
If there are 2 non-metals then the bond is covalent
Water is always polar
Answer:
<u>K (Potassium) and Cl (Chlorine)</u>
Explanation:
Ionic bonds are formed with metals and nonmetals
Covalent bonds are formed only with nonmetals
Calcium and potassium are both metals
Sulfur and Chlorine are both nonmetals so they don't form ionic bonds
Carbon and Oxygen are both nonmetals so they don't form ionic bonds
Answer:
1935100 Bq
Explanation:
Let us recall that:
If 1 μCi can be equivalent to 37000 Bq
Then; the activity of 52.3 μCi will be:
Answer: 2-Pentene
Explanation:
The longest continuous carbon chain that contains the double bond is identified to be Pentene, since it has five carbon atoms.The presence of the double bond makes it an Alkene, hence the -ane ending of the parent Alkane is changed to -ene.
We then do our numbering in the direction that gives the position of the double bond a lower number. Numbering from right to left, the position of the double bond is at carbon atom 2 going to 3, which is lower compared to the other direction.
Hence the name of the compound is 2-Pentene.
Answer:
(a) MOPS
(b) MES
Explanation:
Buffers are solutions whose function is to resist drastic changes in pH when an <em>acid</em> or a <em>base</em> is added. They are formed by 2 components:
- A weak acid and its conjugate base (e.g., HF/F⁻). <u>(acid buffer)</u>
- A weak base and its conjugate acid (e.g., NH₃/NH₄⁺). <u>(basic buffer)</u>
pH and be pOH can be calculated, in each case, according to Henderson-Hasselbalch equations:
pH = pKa + log ([conjugate base]/[weak acid]) <u>(acid buffer)</u>
pOH = pKb + log ([conjugate acid]/[weak base]) <u>(basic buffer)</u>
It is possible to see that when the concentration of acid is equal to that of its base, pH = pKa or pOH = pKb. This is the point where the buffer has its optimum performance. Nevertheless, it has its most effective range of work (buffer range) when the ratio acid:base is between 0.1 and 10. If we take these values into Henderson-Hasselbalch equations, we can see that the optimum range of work is:
- For acid buffer, pH = pKa ± 1
- For basic buffer, pOH = pKb ± 1
In (a) (pH = 7.0), the solution is closet to the pK of the MOPS buffer, so this would be the best choice. Nevertheless, both MES and HEPPS would be suitable options, because their buffer ranges comprise pH = 7.0.
In (b) (pH = 6.0), the solution is closest to the pK of the MES buffer, so this would be the best option. Other buffers are not suitable because pH = 6.0 is out of their buffer range.
