valence of magnesium is 2
and valence of sulfate-ion is 2 too
answer: MgSO4•7H2O
Answer:
work lost due to friction
Explanation:
The work output of any real machine is usually less than the work needed to operate the machine due to the fact that <u>some input work is lost due to friction.</u>
<em>Frictional forces are those forces that oppose the motion of 2 surfaces sliding against each other and this is one of the reasons machines do not work at 100% efficiency. When the opposition happens, some of the input work is converted to heat.</em>
Answer:
Trimethylacetaldehyde
Explanation:
For the <u>unknow compound</u> we have a molar mass of 86 g/mol. We have an even value for the mass, so the compound does <u>not have nitrogen</u> and we can have several posibilities:
A)
B)
C)
D)
If we check the IR info a signal in 1730 cm-1 appears, this indicates that we have an <u>oxo group</u> (C=O). So, the D option can be discarded. The groups that can have the oxo group are: Carboxylic acids, <u>Ketones and aldehydes</u>.
We don have a signal in 3000 cm-1, so the carboxylic acid can be discarded. Now, is we check the info for the 1H NMR we only have 2 signals. If we only have 2 we will have a very<u> symmetric compound</u>.
By trial an error the find the compound <u>Trimethylacetaldehyde</u> (Figure 1).
The answer to the question Retraction. Its because the light goes around it
... in neutralization reactions, for example:
NaOH + HCl = NaCl + H₂O
2KOH + H₂SO₄ = K₂SO₄ + 2H₂O