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2 years ago

What did J.J. Thomson discover about the atom that changed the atomic model previously used?

1 answer:

galina1969 [7]2 years ago

7 0

J.J. Thomson hypothesized and discovered that the atom was not the smallest unit of matter but that instead there were much smaller units. He discovered "sub-atomic particles" which make up atoms. The sub-atomic particle that Thomson discovered was the electron. He discovered this through a process of experiments testing cathode rays.

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Which 2 resonance forms destablize the carbocation intermediate if bezonitrile undergoes chlronation at the ortho or para positi

Anna11 [10]

The question is incomplete, the complete question is shown in the image attached

Answer:

A and B

Explanation:

The electrophilic substitution of arenes yields a cation intermediate. The positive charge of the cation is delocalized over the entire ring.

The -CN group directs incoming electrophiles to the ortho/para position. The resonance structures for the chlorination of benzonitrile are shown in the question.

Recall that -CN is an electron withdrawing group. The resonance forms that destablize the carbocation intermediate are those in which the -CN group is directly attached to the carbon atom bearing the positive charge as in structures A and B.

8 0

3 years ago

Which member of the following pairs has the larger London dispersion forces?

Virty [35]

Answer:

H₂S; CO₂; SiH₄

Explanation:

London dispersion forces are larger in molecules that are large and have more atoms or electrons.

A. H₂O or H₂S

H₂S. S is below O in the Periodic Table, so it is the larger atom. Its electrons are more polarizable.

B. CO₂ or CO

CO₂. CO₂ has more atoms. It is also linear, so the molecules can get close to each other and maximize the attractive forces.

C. CH₄ or SiH₄

CH₄. Si is below C in the Periodic Table, so it is the larger atom. Its electrons are more polarizable.

4 0

2 years ago

The ability of a material is to transmit flux in an electric field is called____

alukav5142 [94]

The answer is A. Permeability.

6 0

2 years ago

A) Calculate the osmotic pressure difference between seawater and fresh water. For simplicity, assume thatall the dissolved salt

never [62]

Answer:

a) Δπ = 1.264 atm

b) W = 128 joules

c) ΔH >> W ( a factor greater than 17,000 )

Explanation:

a) The osmotic pressure, π , is determined by :

π = nRT/V, where n= moles of solute

R= 0.0821 Latm/kmol

T = 300 K

calling π(sw) osmotic pressure for for sea water and π (fw) for fresh water,

salinity of sea water = 3.5 g / 1L water (assuming only NaCl for the salts)

salinity of fresh water = 0.5 parts per thousand (range: 0- 0.5 ppt)

πsw = (3.5 g/58.44 g/mol) (0.0821 Latm/Kmol) (300 K ) /1 L = 1.475 atm

πfw = (0.5 g/58.44 g/mol) (0.0821 Latm/Kmol) (300 K ) /1 L = 0.211 atm

d water = 1 g/cm³

Δ π = (1.475 - 0.211) = 1.264 atm

b) W = Δπ V = 1.426 atm x 1L = 1.43 L-atm

1 L-atm = 101.33 j

W = 101.33 j/ Latm x 1.43 Latm = 128 joules

c) ΔH = Q₁ + nΔH vap, where

Q₁ = heat required to bring the solution from 300 K to boiling, 373 K

ΔH vap = heat of vaporization

Q = mCΔT = 1000 g x 4.186 j x 73 K = 305.6 j = 0.3056 kj

ΔH vap = (1000 g/ 18 g/mol ) 40.7 kj/mol = 2,261 kj

ΔH = 0.3056 kj + 2,261 kj = 2,261.3 kj

Note = Q << ΔH vap and we could have neglected it.

This result shows why nobody talks about evaporation of sea water to produce fresh water ΔH >> W

6 0

3 years ago

If you made a three-dimensional model of an atom and its nucleus, how would you represent the atom? 7th grade

Gemiola [76]

Answer:

it shows the breakdown of the atom

Explanation:

it will show it molecularly

7 0

2 years ago