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otez555 [7]
3 years ago
10

Which statement describes the energy involved in diffusion? Diffusion requires energy in all cases. Diffusion requires energy on

ly to move material in through the cell membrane. Diffusion does not require energy in any situation. Diffusion requires energy only to move material out through the cell membrane.
Chemistry
2 answers:
MArishka [77]3 years ago
3 0

Answer:

Both b and d can be correct

Explanation:

Generally, diffusion does not require energy (<em>making option a wrong</em>) because it is the movement of particles from a region of high concentration to a region of low concentration hence diffusion moves particles in the direction of a concentration gradient. An example of this is the passive transport (for instance, uptake of glucose by a liver cell).

However, in some cases, when diffusion is against the concentration gradient (i.e when particles move from a region of low concentration to a region of high concentration), diffusion will require energy in a case like this (<em>making option c wrong</em>). An example of this is active transport (transport of protein called sodium-potassium pump which involves pumping of potassium into the cell and sodium out of the cell).

The explanation above shows that diffusion can require energy to move particles (in or out) of the cell through the cell membrane.

Nikitich [7]3 years ago
3 0

Answer:

b

Explanation:

You might be interested in
The pH of a solution that is formed by the neutralization of 1.0M H2SO4(aq) and 1.0 M KOH(aq) is closest to
pshichka [43]

Answer:

b) 7

Explanation:

The pH of a solution produced by the neutralization reaction between 1M of H₂SO₄ and KOH with 1M is closest to 7.

pH is a standard for measuring the acidity and alkalinity of a solution. A solution that is acidic will have a pH less than 7, a neutral solution will have pH of 7 and a basic solution will have pH greater than 7.

What is a neutralization reaction?

  • It is an acid-base reaction in which hydrogen and hydroxide ions combines to form water.
  • Also a salt results from the combination of the other ions.

In this reaction a base simply neutralizes an acid and the solution becomes neutral before it goes into completion.

Therefore, a neutral solution will have pH of 7 or close to it.

3 0
3 years ago
Estimate the coordination number for the cations in each of these ceramic oxides and also the coordination numbers of the oxygen
Juli2301 [7.4K]

Answer:

CN cation, anion ] respectively are thus [6,4] , [2,3] ,[6,6] , [6,6] , [6,3] , [12,6,2] , [6], [6].

Explanation:

The coordination number CN is the number of ligand atoms bonded (coordinate bonds) directly to the central of the metal ion. It is not the same as the oxidation state of the metal ion or complex.

Coordination number – the number of anions surrounding the cation.

In solving for CN we need to understand Pauling's rules.

According to Linus Pauling, 1932

“Pauling’s rules” for crystal structures, makes assumptions for ionic bonding. It states that ionic structure is understood using electrostatic rules of attraction and repulsion.

Cations and anions surround each other to neutralize charge – and these one can rationalize crystal structure with coordination number.

Ratio of cationic/anionic radius

• The structure of D-Al2O3 results in coordination number of 6 and 4 for cation and anion respectively.

• The average oxygen coordination number in v-B2O3 is equal to the average cation coordination number × cation/anion ratio (2/3).

• Co-ordination number of Ca2+ ion is =6;

In CaO crystal, Ca2+ is a cation and O2- is an anion. Cationic (Ca2+) has radius 100 pm and anionic (O2-) has radius  145 pm.

Ratio of cationic/anionic radius is:

r⁺/r⁻ = 100 / 145

r⁺/r⁻ = 0.69

CaO will form FCC lattice.

Coordination number in FCC lattice is 6. Therefore CN of Ca2+ = 6.

For MgO:

r Mg2+/ r O2- = 86pm / 126 pm =0.683

The cordination number for the cation is 6. MgO with ions Mg+2 and O-2 will have a AX type stochiometry exhibiting the

crystal structure of sodium chloride.

For TiO2:

The CN of the titanium (IV) cation is 6, which is twice the CN of the oxide anion, which is 3.

This fits with the formula unit of TiO2, since there are twice as many O2− ions as Ti4+ ions.

Consequently the crystal structure of all ionic compounds reflects the formula unit.

For LaAlO3 a Cubic perovskites (ABX3)

In perovskite structures, B cations are coordinated by six X anions, while A

cations present CN = 12 (also coordinated by X anions). The X anions have CN = 2, being

coordinated by two A cations, since the distance A-O is about 40% larger than the B-O

bond distance. The correct ionic radii (rA, rB, rX), taken from one of Shannon’s work.

rA = 1.36 pm

rB = 0.535 pm

rX = 1.35 pm

Forsterite Mg2SiO4

We have mixed sites of Si4+ in tetrahedral site, Mg2+ in octahedral site, O atoms anions .

They all forms octahedral chains/strips. The CN is estimated to (6) octahedral, with an average ratio 0.414

Nickel Cobaltite Ni(Co2O4)3

bidentate ligand includes the Oxalate, three oxalate ligands form six-coordinate bonds around the Ni2+ ion.

Co-ordinate number of Nickel in [Ni(C2​O4​)3​] 4− is 3×2=6.

5 0
3 years ago
Can a cold front warm air moves which direction
Katena32 [7]
East is the cold front
6 0
3 years ago
Urea, (NH2)2CO, is a product of metabolism of proteins. An aqueous solution is 37.2% urea by mass and has a density of 1.032 g/m
Feliz [49]

Answer:

The molarity of urea in this solution is 6.39 M.

Explanation:

Molarity (M) is <em>the number of moles of solute in 1 L of solution</em>;  that is

molarity = moles of solute ÷ liters of solution

To calculate the molality, we need to know the number of moles of urea and the volume of solution in liters. We assume 100 grams of solution.

Our first step is to calculate the moles of urea in 100 grams of the solution,

using the molar mass a conversion factor. The total moles of 100g of a 37.2 percent by mass solution is

60.06 g/mol ÷ 37.2 g = 0.619 mol

Now we need to calculate the volume of 100 grams of solution, and we use density as a conversion factor.

1.032 g/mL ÷ 100 g = 96.9 mL

This solution contains 0.619 moles of urea in 96.9 mL of solution. To express it in molarity, we need to calculate the moles present in 1000 mL (1 L) of the solution.

0.619 mol/96.9 mL × 1000 mL= 6.39 M

Therefore, the molarity of the solution is 6.39 M.

4 0
3 years ago
The Milky Way Galaxy is one of
9966 [12]

Answer:

Billions in the known universe!

Explanation:

Because there are approximately 100 billion galaxies in the observable universe.

Hope it helps!

7 0
3 years ago
Read 2 more answers
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