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andriy [413]
2 years ago
15

Which effect of long-term environmental change is the driving force behind evolution?​

Chemistry
1 answer:
V125BC [204]2 years ago
7 0

Answer:

climate change

Explanation:

climate change is driving force of evolution because when the climate is changed the animal and human need to adapt to it's natural change.

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A compound is 80.0% carbon and 20.0% hydrogen by mass. assume you have a 100.-g sample of this compound. the molar mass of the c
ch4aika [34]
Basis of the calculation: 100g
 
For Carbon: 
 Mass of carbon = (100 g)(0.80) = 80 g
  Number of moles of carbon = (80 g)(1 mole / 12g) = 20/3

For Hydrogen:
  Mass of hydrogen = (100 g)(0.20) = 20 g
     Number of moles of hydrogen = (20 g)(1 mole / 1 g) = 20

Translating the answer to the formula of the substance,
     C20/3H20

Dividing the answer,
    CH3

The molar mass of the empirical formula is:
    12 + 3 = 15 g/mol

Since, the molar mass given for the molecular formula is 30.069 g/mol, the molecular equation is,
    C2H6

ANSWER: C2H6

 
4 0
3 years ago
If hydrofluoric acid is a stronger acid than acetic acid, which statement is most likely true?
Alchen [17]

Answer: The statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.

Explanation:

A strong acid upon dissociation gives a weak conjugate base. This can also be said as stronger is the acid, weaker will be its conjugate base or vice-versa.

Hydrofluoric acid is a strong base as it dissociates completely when dissolved in water.

For example, HF \rightleftharpoons H^{+} + F^{-}

The conjugate base is F^{-} which is a weak base.

Acetic acid is a weak acid as it dissociates partially when dissolved in water. So, the conjugate base of acetic acid is a strong base.

CH_{3}COOH \rightarrow CH_{3}COO^{-} + H^{+}

Thus, we can conclude that the statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.

4 0
3 years ago
SELECT ALL THAT APPLY
Luden [163]
The answer is 1 and 3. The number of atoms per molecule of these three substance is not equal. So they will not contain same number of atoms. And for gas, under same condition with same number of moles will have the same volume. The g.f.w is related to the atomic mass. So they are different.
8 0
3 years ago
Read 2 more answers
What happens to the electronegativity as you go from Lithium to Francium?<br> Why?
Y_Kistochka [10]

Answer:

Electronegativity in group 1 decreases as we go from Lithium to Francium.

Explanation:

Electronegativity is defined as the tendency of an element to attract an electron pair towards itself.

In a group generally this tendency decreases from top to bottom as the size of the atom increases and hence the positive nucleus get far from the outer orbital.

In the same way group 1 elements i.e. from Lithium to Francium electronegativity decreases.

8 0
3 years ago
These questions are from an experiment where we had a mixture of Ferrocene, acetylferrocene and diacetyl ferrocene and we separa
PilotLPTM [1.2K]

Answer:

Explanation:

The polarity of the 3 compounds would be in the order of

Ferrocene < Acetylferrocene < Diacetylferrocene

Your TLC data has to also support this observation . This can be checked by measuring the values of Rf ( Retention factor = distance travelled by solute/solvent ) .The Rf values also has to follow this particular order: -

Ferrocene > acetylferrocene > diacetylferrocene

2) Hexane happens to be a non-polar solvent. The polarity of hexane can be increased if some polar solvents for example, ethyl and methylene chloride etc are added

Therefore, in the increasing order of solvents polarity, we have

Hexane < 1:1 mixture of hexane: methylene chloride < 9:1 mixture of methylene chloride:

3) Chromatographic techniques all have a stationary phase in addition to a mobile phase. In the case of column chromatography, the silica gel will be the stationary phase and the solvent that will be poured will be the mobile phase.

4) The TLC and column chromatography both happen to have the same stationary phase which is the silica gel. Also, the same solvent mixture is used in both the techniques. This makes the result of the 2 to be almost the same. The difference seen between them is that, TLC works against the gravity while on the other hand column chromatography works in the direction of the gravity.

5) The key feature in the IR spectra of the acetylferrocene that will be absent in the spectra of ferrocene is the presence of carbonyl stretching frequency at close to 1700 per cm(cm-1). This peak is easily differentiated between both acetyl ferrocene and ferrocene.

4 0
2 years ago
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