Which pigment is responsible for grey hair?
A
Eumelanin
В
Pheomelanin
с
Both Eumelanin and Pheomelanin
D
No pigment
3 of 10

Answer:

At high pressures and low temperatures.  

Explanation:

That's when the volume of the gas is quite small.

The volume of the gas particles can then be a significant proportion of the total volume.

Answer:

as when we add 60 ml it removes all the protons it means it is 2nd equivalence point of Ascorbic acid

and we know that pH = pKa1 when moles of NaOH is half of the 1st equivalence point

1st equivalence point = 2nd equivalence point / 2 = 60/2 =30ml

1st half equivalence point = 30/2 = 15ml

so when we add 15ml of NaOH

pH = pKa1 =15mL

Answer:

Magma

Explanation:

Magma is the hot liquid under earths surface

Answer:

400 mL

Explanation:

Boyle's Law: [tex]P_1*V_1 = P_2*V_2[/tex]

Let x = the resulting volume

350 (200) = 700 (x)

x = 400 mL

When a chemical reaction releases energy it is called Exothermic Reaction.

hope it helps!

When a chemical reaction energy releases then this type of reaction is called exothermic reaction. In this reaction energy is release to the atmosphere.

In chemistry there are various type of reaction out of which the two main types are the exothermic reaction and endothermic reaction.

Exothermic reaction is the one in which energy releases in form of heat respiration reaction is an example of exothermic reaction. In respiration food that we eat are broken down in glucose with release of energy.

Endothermic reaction is the one in which energy is taken out during the reaction. Photosynthesis is an example of endothermic reaction where sunlight energy is taken by the plants to make food.

Thus when a chemical reaction releases energy these reactions are called exothermic reaction.

To learn more about exothermic reaction, here:

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Answer:

C

Explanation:

heat is energy

Answer:

32.4 L

Explanation:

Note 1:

The Standard Temperature and Pressure (STP) is  defined by IUPAC as air at 0 gradius Celcius and 1 bar.

Note 2:

The Ideal Gas Law is used for solving this problem.

......

Please see the step-by-step solution in the picture attached below.

Hope this answer can help you. Have a nice day!

Answer:

Explanation:

Adding sugar

Answer: 1.42

Explanation:

Answer:

pH = 9.69

Explanation:

When pyridine (C₅H₅N) is added to water, the equilibrium that occurs is:

C₅H₅N(aq) + H₂O(l) ⇌ C₅H₅NH⁺(aq) + OH⁻(aq) Kb = 1.7x10⁻⁹

Where Kb is defined as:

Kb = 1.7x10⁻⁹ = [C₅H₅NH⁺] [OH⁻] / [C₅H₅N]

If you have a solution of 1.4M C₅H₅N, the equilibrium concentration of each specie is:

[C₅H₅N] = 1.4 - X

[C₅H₅NH⁺] = X

[OH⁻] = X

Where X represents the reaction coordinate

Replacing in Kb expression:

1.7x10⁻⁹ = [X] [X] / [1.4 - X]

2.38x10⁻⁹ - 1.7x10⁻⁹X =  X²

0 = X² + 1.7x10⁻⁹X - 2.38x10⁻⁹

Solving for X:

X = -0.0000488M → False answer, there is no negative concentrations

X = 0.0000488M → Right answer

Thus, [OH⁻] = 0.0000488M. As pOH = -log [OH⁻]

pOH = 4.31

Knowing pH = 14 - pOH

pH = 9.69

The pH of a 1.4 M pyridine solution is 9.69. When pyridine (C₅H₅N) is added to water, the equilibrium occurs. The rate of forward reaction is equals to the rate of backward reaction.

When pyridine (C₅H₅N) is added to water, the equilibrium that occurs is:

C₅H₅N(aq) + H₂O(l) ⇌ C₅H₅NH⁺(aq) + OH⁻(aq) Kb = 1.7x10⁻⁹

Where Kb is defined as:

Kb = 1.7x10⁻⁹

Kb= [C₅H₅NH⁺] [OH⁻] / [C₅H₅N]

If you have a solution of 1.4M C₅H₅N, the equilibrium concentration of each specie is:

[C₅H₅N] = 1.4 - x

[C₅H₅NH⁺] = x

[OH⁻] = x

Where x represents the reaction coordinate

Replacing in Kb expression:

1.7*10⁻⁹ = [x] [x] / [1.4 -x]

2.38*10⁻⁹ - 1.7x10⁻⁹x =  x²

0 = x² + 1.7*10⁻⁹x - 2.38*10⁻⁹

Solving for x:

x = 0.0000488M

Thus, [OH⁻] = 0.0000488M.

As pOH = -log [OH⁻]

pOH = 4.31

Knowing pH = 14 - pOH

pH = 9.69

Find more information about Equilibrium constant here:

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Answer:

The porosities in dental materials can be of merit and not merit since some dental materials need to be porous in order to reduce their weight and improve their properties and functions, whereas in those (which are the majority) porosities are not Merit, see the properties of the material, the function and can even influence dental rehabilitation.

An example of this is the use of vitreous ionomers, which is a dental material, where when it is spatulated it remains porous, it can give recurrence of infectious caries, since its permeability increases, the best cariogenic microorganisms are filtered and porosity works as a retentive site for these microorganisms that make up the dental biofilm.

In summary, the world of dental materials is very wide, some are resins, other cements, others have metallic claims, etc. To say that the presence of porosity is merit or demerit would be ideal because for some materials this is favorable and for others unfavorable since they are very versatile, with different qualities, different degrees of porosity, different molecules, different coefficients of thermal expansion, some do not set, others do not, some are light-cured, others do not, some withstand more mechanical forces and have more elastic modulus and less porosity, while others do not, and thus with many more variables.

Explanation:

In the manufacture of dental materials, much attention is always paid to what the manufacturer indicates in these indications that come on the reverse side of the material or on a paper inside the material container.

This is important to know, because the manufacturer is the one that indicates the mode of use and working time according to the trademark and the chemical composition of the dental material.

That a dental material in its manufacture is more or less porous, makes its density, weight and volume possibly be affected, there are materials that seek to increase porosity for a certain purpose, while others seek the opposite, depending on the function that is applied, will have more or less pores.

The example we gave above about the vitreous ionomer is an example that indicates that in the case of restorative dental materials where the function is to SEAL the porosity is almost nil, since otherwise it will not seal the cavity that was formed with caries and not the infectious problem would be solved.

On the other hand, in the surgical field of dentistry there are bone grafts or porous macroparticles that are for the purpose of bone replacement, which in order to be integrated need blood vessels that run over these pores, irrigating the area of ​​bone neoformation well, in this case the merit of porosity if necessary and it is essential that they be very porous.

Answer:

The similarities are the groups, triads law is a law where they are in groups or three, the octaves law is the 'best' law, is the one who every atom wants, they do everything to be in groups of eight.

Explanation:

Answer:

the answer woul be 89 if you do the math right

Explanation:

Answer:

- Increase pressure .

Explanation:

Hello,

In this case, during the dissolution process, the solute's molecules rearrange in order to get together with the solvent's molecules, in this case water.

Now, since we are talking about a solid whose particles are intimately held together, the only way to separate them is by increasing the temperature because the molecules start moving so they can join water's molecules, decreasing particle size since they will be more likely to separate to each other and increasing stirring since the applied energy will break the solid's intramolecular forces.

In such a way, since pressure significantly affects gases and slightly affects liquid, it is not able to modify a solid, just extreme pressures such as it needed to produce diamonds, is able to affect a solid. For that reason, increasing the pressure will not increase the solid's solubility.

Best regards.

Answer:

The mass of zinc sulfide produced is  [tex]M_{ZnS} = 0.76 \ g[/tex]

Explanation:

From the question we are told that

   The mass of zinc is  [tex]m_z = 0.750 \ g[/tex]

    The mass of sulfur is  [tex]m_s = 0.250 \ g[/tex]

The molar mass   of  [tex]Zn_{(s)}[/tex]  is a constant with value  65.39 g /mol

The molar mass of [tex]S_{(s)}[/tex]  is a constant with value  32.01 g/mol

The molar mass of  [tex]ZnS_{(s)}[/tex] is a constant with value 97.46  g/mol

The reaction is  

        [tex]Zn_{(s)} + S_{(s)} ------> ZnS_{(s)}[/tex]

   So from the reaction

       1 mole of  [tex]Zn_{(s)}[/tex] react with 1 mole of  [tex]S_{(s)}[/tex] to produce 1 mole of [tex]ZnS_{(s)}[/tex]

This implies that

65.39 g /mol of  [tex]Zn_{(s)}[/tex] react with 32.01 g/mol of  [tex]S_{(s)}[/tex] to produce   97.46  g/mol  of [tex]ZnS_{(s)}[/tex]

From the values given we can deduce that the limiting reactant is sulfur cause  of the smaller mass

 So  

    0.250 g of  [tex]Zn_{(s)}[/tex] react with 0.250 of  [tex]S_{(s)}[/tex] to produce [tex]x \ g[/tex] of  [tex]ZnS_{(s)}[/tex]

So

      [tex]x = \frac{97.46 * 0.250}{32.01}[/tex]

       [tex]x = 0.76 \ g[/tex]

Thus the mass of the mass of zinc sulfide produced is

    [tex]M_{ZnS} = 0.76 \ g[/tex]

Answer:

A) They all have 12 protons.

Explanation:

Magnesium has an atomic number of 12 which means it has 12 protons. All Magnesium atoms have 12 protons, the neutrons however may differ which produces things called isotopes where the atoms have same protons but neutrons change.

Keep in mind the atomic number is unique to each element, so 12 atomic number will always be Magnesium, 1 will always be Hydrogen and so on.....

Answer:

vent vapor concentration in the air to nearly zero. The effective diffusion coefficient of the solvent molecules in the polymer is 2 x 10^-6 cm^2/s

Explanation:

Answer:

See explaination

Explanation:

When ignited, hydrogen gas combines with oxygen gas explosively in proportions ranging from 4.1 - 71.5% hydrogen - ignition temperature is 580 °C. The gaseous reaction is

2 H2(g) + O2(g) → 2 H2O(g)

This exothermic reaction yields 232 kJ/mol of water formed. The rapid release of a considerable amount of energy causes the surrounding air to expand suddenly, resulting in a sharp expolsion. When pure hydrogen is ignited, the reaction with the surrounding air is less rapid, the sound is less loud, and a significantly larger flame is produced.

The amount of water produced directly influences the amount of heat produced and the amount of energy released. If the two gases are in the correct ratio of 1 oxygen to 2 hydrogen we get the loudest sound as the maximum amount of water is produced for the same volume of the balloon.

For any ration away from 1 oxygen to 2 hydrogen by volume and mole we will get a less louder sound. The farther we are away from this ratio the lesser amount of water is formed and thus lesser heat released and lesser sound.

To demonstrate let us take 4 balloons

Balloon A 1: 2 oxygen to hydrogen

Baloon B 1.2 : 1.8 oxygen and hydrogen

Balloon C 1:1 oxygen to hydrogen

Balloon D 2:1 oxygen to hydrogen

So we will see A is the loudest followed by B, C and least loud is D.

After the body is cleaned, the body is weighed and measured before being placed on the autopsy table for reexamination. The autopsy table is typically a slanted, aluminum table with raised edges that has several faucets and drains used to wash away collecting blood during the internal investigation.

Answer:

A table used to scientifically determine the cause of death of a human or animal

Explanation:

Answer:

26 mol

Explanation:

Step 1: Write the balanced equation

4 FeCl₃ + 3 O₂ ⇒ 2 Fe₂O₃ + 3 Cl₂

Step 2: Determine the appropriate molar ratio

The molar ratio of FeCl₃ to O₂ is 4:3.

Step 3: Use the determined molar ratio to calculate the moles of oxygen required to completely react with 35 moles of ferric chloride

[tex]35molFeCl_3 \times \frac{3molO_2}{4molFeCl_3} = 26molO_2[/tex]

Answer:

[tex]n_{O_2}=26.25molO_2[/tex]

Explanation:

Hello,

In this case, given the reaction:

[tex]4FeCl_3 + 3O_2 \rightarrow 2Fe_2O_3 + 6Cl_2[/tex]

Since oxygen and iron (III) chloride are in a 4:3 molar ratio, he required moles of oxygen to completely react with 35 moles of iron (III) chloride result:

[tex]n_{O_2}=35molFeCl_3*\frac{3molO_2}{4molFeCl_3} \\\\n_{O_2}=26.25molO_2[/tex]

Best regards.

Answer:

C) Integumentary, nervous, muscular

Explanation:

When a human body touches a hot stove , our sense organ which is integumen first of all receives the impulse of heat . The impulse is transformed into electrical signal which is transmitted to brain which is a part of nervous system . Then brain processes it and command signal is sent to muscle of hand to move it away from that place . Hence the order is

Integumentary, nervous, muscular .

Answer:

.6mol/L

Explanation:

molarity = number of moles / volume of solvent (in L)

750mL / 1000mL/L = .75L

M = .450mol / .75L

M = .6mol/L

Explanation:

MnO4−+ SO32− → Mn2++ SO42−

Splitting into half equations;

MnO4−  → Mn2+

SO32− → SO42−

Balancing the electrons;

2 MnO4−  + 10 e- → 2Mn2+

5SO32− → 5SO42− + 10 e-

In an acidic medium, it becomes;

2 MnO4−  +  8 H+ → 2 Mn2+ + 4 H2O

5 SO32−  + H2O → 5 SO42−  +  2 H+

Final equation is;

2 MnO4- + 5 SO32- + 6 H+ → 2 (Mn)2+ + 5 SO42- + 3 H2O

Coefficient of H+ = 6

Coefficient of H2O = 3

Coefficient of MnO4- = 2

Coefficient of SO32- = 5

Coefficient of (Mn)2+- = 2

Coefficient of SO42- = 5

Answer:

[tex]5SO_3^{2-}+2MnO_4^{-}+6H^+ \rightarrow 5SO_4^{2-}+ 2Mn^{2+}+3H_2O[/tex]

Explanation:

Hello,

In this case, given the reaction:

[tex]MnO_4^{-}+ SO_3^{2-} \rightarrow Mn^{2+}+ SO_4^{2-}[/tex]

We first identify the oxidation state of both manganese and sulfur at each side:

[tex]Mn^{7+}O_4^{-}+ S^{4+}O_3^{2-} \rightarrow Mn^{2+}+ S^{6+}O_4^{2-}[/tex]

So we have the oxidation and reduction half-reactions below, including the addition of water and hydronium as it is in acidic media:

[tex]S^{4+}O_3^{2-}+H_2O \rightarrow S^{6+}O_4^{2-}+2H^++2e^-[/tex]

[tex]Mn^{7+}O_4^{-}+8H^++5e^- \rightarrow Mn^{2+}+4H_2O[/tex]

Next, we exchange the transferred electrons:

[tex]5*(S^{4+}O_3^{2-}+H_2O \rightarrow S^{6+}O_4^{2-}+2H^++2e^-)\\2*(Mn^{7+}O_4^{-}+8H^++5e^- \rightarrow Mn^{2+}+4H_2O)\\\\5S^{4+}O_3^{2-}+5H_2O \rightarrow 5S^{6+}O_4^{2-}+10H^++10e^-\\2Mn^{7+}O_4^{-}+16H^++10e^- \rightarrow 2Mn^{2+}+8H_2O[/tex]

Then we add the resulting half-reactions and simplify the transferred electrons:

[tex]5S^{4+}O_3^{2-}+5H_2O+2Mn^{7+}O_4^{-}+16H^+ \rightarrow 5S^{6+}O_4^{2-}+10H^++ 2Mn^{2+}+8H_2O[/tex]

We rearrange the terms in order to simplify water and hydronium molecules:

[tex]5S^{4+}O_3^{2-}+2Mn^{7+}O_4^{-}+16H^+-10H^+ \rightarrow 5S^{6+}O_4^{2-}+ 2Mn^{2+}+8H_2O-5H_2O\\\\5S^{4+}O_3^{2-}+2Mn^{7+}O_4^{-}+6H^+ \rightarrow 5S^{6+}O_4^{2-}+ 2Mn^{2+}+3H_2O[/tex]

Finally we write the balanced reaction in acidic media:

[tex]5SO_3^{2-}+2MnO_4^{-}+6H^+ \rightarrow 5SO_4^{2-}+ 2Mn^{2+}+3H_2O[/tex]

Best regards.

Answer:

The correct answer is the second last statement, that is, it affects the energy levels of the metal d orbitals.

Explanation:

It is because of the d-d transition of electrons that the metal complexes exhibit color. When bonding of the ligands takes place with the transition metal ion, a repulsion results between the electrons in the d orbitals of the metal ion and the electrons found within the ligands. This increases the d orbitals' energy level.  

However, based on the alignment of the d orbitals in the space, all of the energies do not get elevated by the same level, it gets dissociate into two groups. This dissociation of the d-orbitals relies upon the ligand's strength. More amount of energy would be required to encourage an electron from the lower orbitals groups to the move towards the higher ones in case if the splitting is more.  

Greater energy is equivalent to shorter wavelengths in terms of the color of the light absorbed. The complex ions possessing different ligands show distinct kinds of colors as the energy levels of the d orbitals of the metal get affected by the ligands.  

Answer:

2 HCl

Explanation:

Please kindly check attachment for the step by step solution of the given problem.

A crystal of table salt (NaCl) is dissolved in water. Which of the following statements explains why the dissolved salt does not recrystallize as long as the temperature and the amount of water stay constant?

Na+ and Cl- ions lose their charges in the water.

Water molecules surround the Na+ and Cl- ions.

Na+ and Cl- ions leave the water through vaporization.

Water molecules chemically react with the Na+ and Cl- ions.

Your answer: -

Answer: B - Water molecules surround the Na+ and Cl- ions.

Answer:

.01

Explanation:

H30+=10^-pH

- Hope that helps! Please let me know if you need further explanation.

Answer:carbon, hydrogen and oxygen

Explanation:

Alcohol functional group is composed of carbon, hydrogen and oxygen

Answer:

Actual yield reduces the more.

Explanation:

An actual yield of the course of a chemical reaction is the mass of a product actually obtained from the reaction.

In practice you see it and It is usually less than the theoretical yield.

Various reasons may come up to explain this away but here is one:

• incomplete reactions, simply put here some of the reactants do not react to form the product.

The same applies in the question about the actual yield will reduce significantly in molar mass now that insufficient amount of reagent are used.

Answer:

b, c, e

Explanation:

Inorganic compounds usually lack carbon.

Inorganic compounds are not associated with or made from living things.

Inorganic compounds include salt and water​.

Answer:

yes the answer id bce

Explanation: