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Stolb23 [73]
3 years ago
13

Why is the expectation value of the energy associated with the 1-D "particle-in-a-box" the same as the eigen value of the Hamilt

onian associated with the 1-D "particle-in-a-box" wave function?
Chemistry
1 answer:
Veronika [31]3 years ago
4 0

Answer: The average potential energy of the PIB is 0 irrespective of the wave function.

Explanation:

⟨H⟩=⟨KE⟩+⟨V⟩

the nn quantum number

⟨KE⟩=(π^2 ℏ^2)/(2mL^2 )

the average kinetic energy of the wavefunction is dependent on

⟨V⟩=∫sin(kx)0sin(kx)dx=0

The average potential energy of the PIB is 0 irrespective of the wave function.

⟨H⟩=⟨KE⟩=(π^2 ℏ^2)/(2mL^2 )

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List 6 uses of acids
devlian [24]

Answer: 1. Vinegar, used in the kitchen, is a liquid containing 3-6% acetic acid. It is used in pickles and in many food preparations.

2. Lemon and orange juice contains citric acid. Citric acid is used in the preparation of effervescent salts and as a food preservative.

3. Acids have been put to many uses in industry. Nitric acid and sulphuric acid are used in the manufacture of fertilizers, dyes, paints, drugs and explosives.

4. Sulphuric acid is used in batteries, which are used in cars, etc. Tannic acid is used in the manufacture of ink and leather.

5. Hydrochloric acid is used to make aqua regia, which is used to dissolve noble metals such as gold and platinum.

6. Sulphuric acid is used in manufacturing fertilizers such as super phosphate, ammonium sulpahte etc.

8 0
3 years ago
ethanol is a common laboratory solvent and has a density of 0.789 g/mL. what is the mass, in grams, of 151 mL of ethanol
natta225 [31]
<em>V = 151 mL = 151 cm³</em>
<em>d = 0,789 g/mL = 0,789 g/cm³</em>
--------------------------------------

d = m/V
m = d×V
m = 0,789×151
<u>m = 119,139g</u>

3 0
4 years ago
Read 2 more answers
What volume of water has the same mass as 9.0m3 of ethyl alcohol?
Triss [41]
This question requires the knowledge of density. 

The density of ethyl alcohol = 789 kg m⁻³
The density of water = 1000 kg m⁻³

Density = Mass / Volume 

By applying ethyl alcohol,
    789 kg m⁻³ = Mass / 0.9 m³
         Mass     = 710.1 kg
hence the mass of 0.9 m³ ethyl alcohol is 710.1 kg.

Then by applying water,
     1000 kg m⁻³ = 710.1 kg / Volume
      Volume        = 0.7101 m³
                          = 0.7 m³
hence the equal water volume is 0.7 m³
8 0
3 years ago
Anyone think they can help me with this one?
BARSIC [14]
To name this Alkyne, simply count from the direction that will give the lowest starting number to appear at the beginning of the carbon triple bond.

If you were to count from the top of the chain, the position of the carbon next to the triple bond would be 4. Yet if you count from the bottom chain going left to right and above the chain, the position of the carbon next to the triple bond would be 3.

Then identify the groups that are connected off the parent chain, here we have a methyl group on carbon 2.

Thus the name would be 2 - methyl - 3 - heptyne. I believe.
4 0
3 years ago
What we call "tin cans" are really iron cans coated with a thin layer of tin. The anode is a bar of tin and the cathode is the i
UNO [17]

Answer:

Fe (s) + Sn^{2+} (aq)\rightarrow Fe^{2+} (aq) + Sn (s)

Explanation:

Although the context is not clear, let's look at the oxidation and reduction processes that will take place in a Fe/Sn system.

The problem states that anode is a bar of thin. Anode is where the process of oxidation takes place. According to the abbreviation 'OILRIG', oxidation is loss, reduction is gain. Since oxidation occurs at anode, this is where loss of electrons takes place. That said, tin loses electrons to become tin cation:

Sn (s)\rightarrow Sn^{2+} (aq) + 2e^-

Similarly, iron is cathode. Cathode is where reduction takes place. Reduction is gain of electrons, this means iron cations gain electrons and produce iron metal:

Fe^{2+} (aq) + 2e^-\rightarrow Fe (s)

The net equation is then:

Sn (s) + Fe^{2+} (aq)\rightarrow Fe (s) + Sn^{2+} (aq)

However, this is not the case, as this is not a spontaneous reaction, as iron metal is more reactive than tin metal, and this is how the coating takes place. This implies that actually anode is iron and cathode is tin:

Actual anode half-equation:

Fe (s)\rightarrow Fe^{2+} (aq) + 2e^-

Actual cathode half-equation:

Sn^{2+} (aq) + 2e^-\rightarrow Sn (s)

Actual net reaction:

Fe (s) + Sn^{2+} (aq)\rightarrow Fe^{2+} (aq) + Sn (s)

6 0
3 years ago
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