18.The octet rule tells us that in every chemical
reactions, elements will either gain or lose electrons to attain the noble gas electron
configuration. This stable<span> electron configuration is known as the octet configuration
since it is composed of 8 valence. Oxygen’s electron configuration is 1s2 2s2
2p4. So when</span> oxygen reacts with
other elements to form compounds, it completes the octet configuration by
taking 2 electrons from the element
it reacts with
19. Actually pure metals are made up not of
metal atoms but rather of closely packed cations (positively charge particles).
These cations are then surrounded by a pack of mobile valence electrons which
drift from one part of the metal<span> to
another. This is called metallic bond.</span>
20. This is the
energy which is needed to break a single bond. When the dissociation energy is
large, this means that the compound is more stable. Since carbon to carbon
bonds have high dissociation energy, therefore they are not very reactive.
21. Network solids are type of solids
in which the atoms are covalently bonded to one another, so they are very
stable. It takes higher temperature to melt them because breaking these
covalent bonds required greater energy. Some examples are:
- Diamond
<span>-Silicon Carbide</span>
Answer:
A. Strong initial heating caused some of the hydrate sample to spatter out of the crucible.
Explanation:
Hi
The percentage of water in the sample is lower than expected.
A. Strong initial heating caused some of the hydrate sample to spatter out of the crucible:
If part of the sample is splashed from the crucible the mass of water detected will be less.
B. The dehydrated sample absorbed moisture after heating:
If the sample absorbs water after heating the percentage of water would be higher than expected.
C. The amount of the hydrate sample used was too small:
Depending on the sample size, different procedures can be chosen for analysis.
D. The crucible was not heated to constant mass before use:
In many occasions the crucible is heated next to the sample and not in previous form.
E. Excess heating caused the dehydration sample to decompose:
If the sample decomposes during heating, the analysis should be discarded.
success with your homework
Answer:
A.it is converted into thermal energy
Answer:
C. chromium is a metal that is less reactive than sodium.
Explanation:
Hello.
Given the options:
A. chromium is a nonmetal and therefore a good conductor of heat and electricity
.
B. chromium is a metal that is more reactive than potassium
.
C. chromium is a metal that is less reactive than sodium
.
D. chromium is a noble gas that is not reactive.
In this case, since chromium is in period 4 group VIB we infer it is a transition metal which slightly reacts with acids and poorly reacts with oxygen and other oxidizing substances. Thus, in comparison with both sodium and potassium which are highly reactive even with water as they get on fire, we can say that it is less reactive than both potassium and sodium, therefore, answer is: C. chromium is a metal that is less reactive than sodium.
Best regards.
The answer for this one is a
