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4 years ago

I NEED HELP PLEASE, THANKS!! :)

Chemistry

2 answers:

Blizzard [7]4 years ago

8 0

Answer:

C. submicroscopic

Explanation:

I am not sure but I think the best answer here is C, because "submicroscopic" means "too small to be seen by an ordinary light microscope". And because the name of this aparatus sounds so specifically, the answer B - microscopic - not seems to be the best.

"Scanning Tunnelling Microscopy" (STM) is a technique that has been used for the surface study of NANOSTRUCTURES using the chemical composition of atoms and molecules in NPs to image surfaces at atomic level. - This is the definition of STM. It includes the word NANOSTRUCTURES, so the answer C must be the best one.

In-s [12.5K]4 years ago

5 0

Answer:

B) microscopic

Explanation:

A scanning tunneling microscope allows imaging of microscopic particles.

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Answer:

C-BY LOSING ONE OR MORE ELECTRONS

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2 years ago

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How does the kinetic-molecular theory explain the following properties of liquids:

Tcecarenko [31]

Answer:

"Kinetic energy of the gas is more as compared to that of the liquids. But when compare it to the solid, kinetic energy of liquid is more."

Explanation:

a) Relatively high density : This happens as a result of the tight or packed or can be say close arrangement of the particles.

b) Ability to diffuse : As we know that in gases the constant and the random motion of the particles of the liquid leads to diffusion. But it is very slow as compared to the gases and also porque liquid particles are close together.

c) Ability to evaporate:This happens as a result of the molecules of the liquid having different kinetic energies with particles having higher than that of the average energies that move faster.

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4 years ago

I2(g) + Cl2(g)2ICl(g) Using standard thermodynamic data at 298K, calculate the entropy change for the surroundings when 1.62 mol

galina1969 [7]

Answer:

The change in entropy of the surrounding is -146.11 J/K.

Explanation:

Enthalpy of formation of iodine gas = $\Delta H_f_{(I_2)}=62.438 kJ/mol$

Enthalpy of formation of chlorine gas = $\Delta H_f_{(Cl_2)}=0 kJ/mol$

Enthalpy of formation of ICl gas = $\Delta H_f_{(ICl)}=17.78 kJ/mol$

The equation used to calculate enthalpy change is of a reaction is:

$\Delta H_{rxn}=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]$

For the given chemical reaction:

$I_2(g)+Cl_2(g)\rightarrow 2ICl(g),\Delta H_{rxn}=?$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(2\times \Delta H_f_{(ICl)})]-[(1\times \Delta H_f_{(I_2)})+(1\times \Delta H_f_{(Cl_2)})]$

$=[2\times 17.78 kJ/mol]-[1\times 0 kJ/mol+1\times 62.436 kJ/mol]=-26.878 kJ/mol$

Enthaply change when 1.62 moles of iodine gas recast:

$\Delta H= \Delta H_{rxn}\times 1.62 mol=(-26.878 kJ/mol)\times 1.62 mol=-43.542 kJ$

Entropy of the surrounding = $\Delta S^o_{surr}=\frac{\Delta H}{T}$

$=\frac{-43.542 kJ}{298 K}=\frac{-43,542 J}{298 K}=-146.11 J/K$

1 kJ = 1000 J

The change in entropy of the surrounding is -146.11 J/K.

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3 years ago

The Tin Pan Alley era lasted from 1950 to 1967. a. true b. false

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3 years ago

An ice-skating rink has tubes under its floor to freeze the water. salt water is cooled well below the freezing point of water a

alex41 [277]

Correct Answer: Option g: adding salt to water lowers its freezing point

Reason:
Freezing point is a colligative property. When a non-volatile solution is present in solution, it's freezing point decreases. This is referred as depression in freezing point (ΔTf). Extent of lowering in freezing point is dependent on number of particles present in system. Mathematically it is expressed as:

ΔTf = Kf X m

where, m = molality of solution
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Hence, adding salt to water lowers the freezing point of solution.

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3 years ago