1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Kobotan [32]
3 years ago
8

Impure compounds tend to have lower melting points than pure samples. Explain why this occurs, using biphenyl as an example. Mak

e sure you consider what happens upon melting in molecular terms. (b) Is recrystallization a suitable method for purifying all types of organic compounds? If not, why not?
Chemistry
1 answer:
Oduvanchick [21]3 years ago
5 0

Explanation:

(a)

Substances with impurity melts at lower temperature and this phenomenon is called depression in melting point.  

Pure solid organic compounds or inorganic compounds tend to have highly packed structure. When a substance melts, these arrangements are disturbed. Impurities disrupt the regular arrangement of the crystals. Therefore, If impurities are present within the crystals, less energy are required to disturb the crystal, therefore, melts at lower temperature.

(b)

Recrystallization is not a suitable method for the purification of all organic compounds.

In recrystallization, organic compounds are dissolved in a suitable solvent at high temperature. After that solution is cooled slowly. During cooling process, the crystals of organic compound separate from the solution and impurities are left in the solution.

So, finding a suitable solvent for a solid organic compound is difficult. Moreover, liquid organic compounds cannot be purified by this method.

You might be interested in
List the following bond types in order of increasing strength: non-polar covalent bonds, ionic bonds, hydrogen bonds, polar cova
ss7ja [257]

Answer: Option (B) is the correct answer.

Explanation:

  • An ionic bond is formed by the sharing of electrons between two chemically combining atoms.

In an ionic bond, there occurs attraction between oppositely charged ions due to which there occurs strong forces of attraction between them. Therefore, ionic bonds are the strongest bonds.

  • A polar covalent bond is formed due to unequal sharing of electrons between the combining atoms.

For example, H_{2}O is a polar covalent compound. Partial opposite charges tend to develop on the atoms of a polar covalent compound.

  • A non-polar covalent bond is formed due to equal sharing of electrons between the combining atoms.

For example, Cl_{2} is a non-polar covalent molecule. No partial charges will be there on the atoms of a non-polar covalent molecule.

  • A hydrogen bond is defined as the bond formed between a hydrogen atom and an electronegative atom.

For example, in HCl compound there occurs hydrogen bonding.

In this type of bond, dipole-dipole attractive interactions tend to take place. And, strength of hydrogen bonds is very weak.

Thus, we can conclude that given bond types are arranged in order of increasing strength as follows.

      Hydrogen bonds < non-polar covalent bonds < polar covalent bonds < ionic bonds

8 0
3 years ago
The purpose of the salt bridge in an electrochemical cell is to ____.
IgorLugansk [536]

Answer:

A. maintain electrical neutrality in the half-cells via migration of ions

Explanation:

Salt bridge -

For an electrochemical reaction , involving an anode and a cathode , both the electrodes are connect via a salt bridge to complete the circuit for the reaction .

One of the very important use of a salt bridge is to maintain the electrical neutrality of the respective half cells , which is achieved by the movement of ions .

Hence , from the given options , the correct option is ( a ) .

8 0
3 years ago
Explain why metals are good conductors of electric current.
Phantasy [73]
For example, copper is used for electrical<span> wiring because it is a </span>good conductor of electricity<span>. </span>Metal<span> particles are held together by strong metallic bonds, which is why they have high melting and boiling points. The free electrons in </span>metals<span> can move through the </span>metal<span>, allowing </span>metals<span> to conduct </span>electricity<span>.</span>
5 0
3 years ago
Read 2 more answers
It was calculated that 4.3mL of 0.417 M HCl is required to titrate 11.9 mL of 0.151 M Mg(OH)2. Show evidence 2 HCl(aq) + Mg(OH)2
Lapatulllka [165]

Answer:

See explanation.

Explanation:

Hello,

In this case, for the described chemical reaction:

2 HCl(aq) + Mg(OH)2(aq) → MgCl2(aq) + 2 H2O(l)

We can notice there is a 2:1 molar ratio between the moles of hydrochloric acid and magnesium hydroxide, therefore, at the equivalence point:

n_{HCl}=2*n_{Mg(OH)_2}

And in terms of volumes and concentrations we verify:

V_{HCl}M_{HCl}=2*V_{Mg(OH)_2}M_{Mg(OH)_2}

So we use the given data to proof it:

4.3mL*0.417M=2*11.9mL*0.151M\\1.793=3.594

Therefore, we can conclude the data is wrong by means of the 2:1 mole ratio that for sure was not taken into account. This is also supported by the fact that normalities are actually the same, but the nomality of magnesium hydroxide is the half of the hydrochloric acid normality since the acid is monoprotic and the base has two hydroxyl ions.

Best regards.

4 0
3 years ago
In the example, the final kinetic energy is determined to be ___________ because at the peak height, the ball instantaneously st
alina1380 [7]

TLDR: The kinetic energy is determined to be zero.

Kinetic energy is energy of motion; when an object is moving (i.e. it has speed or velocity), it has some amount of kinetic energy. The equation itself looks like so:

KE=1/2(m)(v)^2,

where "m" represents the mass of the object and "v" represents the objects speed or velocity. In this example, the ball has stopped, meaning it has no speed/velocity. This means that the final kinetic energy is determined to be zero or none, due to the lack of motion. Mathematically, you can see this by substituting "0" in for "v" (the ball is stopped):

KE=1/2(m)(v)^2

KE=1/2(m)(0)^2

KE=1/2(m)*0

KE=1/2*0

KE=0 J,

or zero kinetic energy.

Hope this helps! :)

7 0
3 years ago
Read 2 more answers
Other questions:
  • Study the ions that contain the element chlorine. What are some similarities between the formulas for these ions?
    15·1 answer
  • Whats a electron please help meeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
    13·2 answers
  • You are driving a Winnebago at a casual speed of 54 miles per hour (mph) on a journey to visit your grandmother in Alabama.
    6·1 answer
  • 30 POINTS
    9·2 answers
  • Which statement best describes how electrons fill orbitals in the periodic table? Electrons fill orbitals in order of their incr
    12·2 answers
  • Which sample of matter is classified as a substance
    5·1 answer
  • Como transformar -80°K a °C​
    8·1 answer
  • This type of erosion picks up materials and transports them in the air, often causing the abrasion of surfaces.
    12·1 answer
  • A chemist adds 370.0mL of a 1.41/molL potassium iodide KI solution to a reaction flask. Calculate the millimoles of potassium io
    8·1 answer
  • How to light a candle without touching it?​
    12·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!