Answer:The endpoint does not correspond exactly to the equivalence point
At the endpoint, a change in a physical quantity associated with the equivalence point occurs.
At the equivalence point, the mole number of equivalents of reagent added is equal to the mole number of equivalents of analyte present.
Explanation:
The end point is always indicated by some physical property that changes such as colour. At the equivalence point, the mole number of equivalents of reagent added is equal to the mole number of equivalents of analyte present. The equivalence point cannot be physically observed but can be deduced after a titration curve is plotted.
Answer:
B. –99 kJ.
Explanation:
We have the following information:
1. C(s) + O₂(g) → CO₂(g);
ΔH = -393 kJ
2. 2CO(g) + O₂ → 2CO₂(g);
ΔH = -588 kJ
Using Hess's Law, Our target equation has C(s) on the left hand side, so we re-write equation 1:
1. C(s) + O₂(g) → CO₂(g);
ΔH = -393 kJ
So, we reverse equation 2 and divide by 2, we have equation 3:
3. CO₂(g) → CO(g) + ½O₂;
ΔH = +294 kJ
That is, change the sign of ΔH and divide by 2. Then we add equations 1 and 3 and their ΔH values.
This gives:
C(s) +½O₂(g) → CO(g);
ΔH = +294 - 393 kJ
= -99 kJ
The standard enthalpy of formation of carbon monoxide is -99 kJ/mol.
A conjugate acid<span>, within the </span>Brønsted–Lowry acid–base theory<span>, is a </span>species<span> formed by the </span>reception of a proton<span> (</span><span>H+</span><span>) by a </span>base<span>—in other words, it is a base with a </span>hydrogen<span> ion added to it. The conjugate acid would be as follows:
</span><span>Cl = HCl
CH2 = </span>H2O<span>
CO2- = </span><span>HCO3(1-)</span>
Thee question is incomplete; the complete question is;
Which elements do not strictly follow the octet rule when they appear in the Lewis structure of a molecule?
Select one or more:
A: Chlorine
B: Carbon
C: Hydrogen
D: Sulfur
E: Fluorine
F: Oxygen
Answer:
chlorine
sulphur
Explanation:
The octet rule states that, for atoms to be stable, they must have eight electrons on their outermost shells.
This rule is not strictly followed by some elements such as sulphur and chlorine. The atoms of these elements can sometimes expand their octet by utilizing the d-orbitals found in the third principal energy level and beyond.
These leads to formation of compounds in which the central atom has more than eight electrons in its outermost shell.
