Classify each cation as a weak acid or pH neutral (neither acidic nor basic).

a. Na+
b. Ni2+
c. NH4+

Answer:

only one substrate could be converted to product by the enzyme

Explanation:

If an enzyme obeys the lock and key model, it then follows that the design of the enzyme is unique to a particular substrate.

Just as only the correct key can effectively fit into a lock, only the appropriate substrate whose design matches that of the enzyme can fit into the enzyme.

Owing to the lock and key model of enzyme activity, only one enzyme could interact with a substrate to yield particular product.

Answer:

Please find the complete solution in attached file.

Explanation:

Periodic law is the the properties of the elements that repeat in a regular way as the atomic numbers increase.

Periodic chart organized collection of all chemical elements arranged roughly according to increasing atomic weight. The periodic recurrence of several features in the elements was originally identified by Dmitry I. Mendeleyev in 1869.

1. This is a vertical arrangement of elements in the periodic table   group

2. This is a horizontal arrangement of elements in the periodic table   period

3. The properties of the elements repeat in a regular way as the atomic numbers increase periodic law

4. Element 19 begins this arrangement in the periodic table period

5. The chemical properties of elements 12, 20, and 38 demonstrate this principle.  periodic law

Therefore, periodic law is the the properties of the elements that repeat in a regular way as the atomic numbers increase.

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Answer:

a. minus 10

Explanation:

An element in group 13 = Boron ,valence electrons = 3 , therefore, valence electrons in group 13 = group no. -10

An element in group 18 = Neon, valence electrons = 8 , therefore, valence electrons in group 18 = group no. - 10

For groups 13 through 18, the number of valence electrons in an atom is equal to the group number minus 10. Therefore, option (A) is correct.

Valence electrons in an atom can be described as the electrons occupying the outer most electron shell of an atom while the electrons in the inner shell are core electrons. Lewis structures can be helpful to calculate the number of valence electrons.

Valence electrons can be filled in several electron shells as they are caused interaction between atoms and responsible for the formation of chemical bonds. Only valence electrons can contribute to the formation of a chemical bond and decide the reactivity of the element.

The general electronic configuration of group 13 is ns²np¹ has three valence electrons. It can be determined as group number - 10 = 13 - 10 = 3.

The general electronic configuration of group 18 is ns²np⁶ has eight valence electrons. It can be determined as group number - 10 = 18 - 10 = 8.

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Answer:

Changes of state occur at segment

✔ B–C

and segment

✔ D–E

Explanation:

got it right on edge :)

The amount of energy added to the ice between Point A and Point D is approximately 25 kJ.

To calculate the amount of energy added to the ice between Point A and Point D, we need to consider the different stages of the heating curve.

Heating the ice from -20°C to 0°C:

The energy required to raise the temperature of the ice can be calculated using the specific heat of ice (2.10 J/(g·°C)) and the mass of the ice (60.0 g). The temperature change is from -20°C to 0°C, which is a total of 20 degrees.

Energy = mass × specific heat × temperature change

Energy = 60.0 g × 2.10 J/(g·°C) × 20°C

Energy = 2520 J

Melting the ice at 0°C:

The energy required to melt the ice can be calculated using the latent heat of fusion of ice (333.4 J/g) and the mass of the ice (60.0 g).

Energy = mass × latent heat of fusion

Energy = 60.0 g × 333.4 J/g

Energy = 20,004 J

Heating the water from 0°C to 15°C:

The energy required to raise the temperature of the water can be calculated using the specific heat of water (4.18 J/(g·°C)) and the mass of the water (60.0 g). The temperature change is from 0°C to 15°C, which is a total of 15 degrees.

Energy = mass × specific heat × temperature change

Energy = 60.0 g × 4.18 J/(g·°C) × 15°C

Energy = 3753 J

The total energy added to the ice between Point A and Point D is the sum of the energy calculated in each step:

Total Energy = Energy (Heating ice) + Energy (Melting ice) + Energy (Heating water)

Total Energy = 2520 J + 20,004 J + 3753 J

Total Energy = 25,277 J

Converting this energy to kilojoules (kJ):

Total Energy = 25,277 J ÷ 1000

Total Energy = 25.277 kJ

Therefore, the amount of energy added to the ice between Point A and Point D is approximately 25 kJ.

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Answer:

See explanation

Explanation:

First we divide the percentage by mass of each element by it's relative atomic mass then we divide the quotients obtained by the lowest ratio obtained in the first step.

C- 76.57/12, H= 6.43/1, O = 17.00/16

C- 6.38/1.06, H= 6.43/1.06, O= 1.06/1.06

C- 6, H- 6, O- 1

Empirical formula: C6H6O

[(12 ×6) + (6 × 1) + (16 × 1)]n=94.11

[72 + 6 +16]n = 94.11

n = 94.11/94

n= 1

Molecular formula = C6H6O

2)

C- 53.30/12, H- 11.19/1, O- 35.51/16

C- 4.44/2.22, H- 11.19/2.22, O- 2.22/2.22

C- 2, H- 5, O- 1

Empirical formula: C2H5O

[(2×12) + (5× 1) + (1×16)]n = 90.12

[24 + 5 + 16] n = 90.12

n= 90.12/45

n= 2

Molecular formula = C4H10O2

Answer:

0.5024 g

Explanation:

Step 1: Calculate the concentration of H⁺

We will use the definition of pH.

pH = -log [H⁺]

[H⁺] = antilog -pH = antilog -12.40 = 3.981 × 10⁻¹³ M

Step 2: Calculate the concentration of OH⁻

We will use the ionic product of water expression.

[H⁺] [OH⁻] = 10⁻¹⁴

[OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/3.981 × 10⁻¹³ = 0.02512 M

Step 3: Calculate the initial concentration of NaOH

NaOH is a strong base and the molar ratio of NaOH to OH⁻is 1:1. Thus, the initial concentration of NaOH is 1/1 × 0.02512 M = 0.02512 M.

Step 4: Calculate the moles of NaOH

We will use the definition of molarity.

M = moles of NaOH/liters of solution

moles of NaOH = M × liters of solution

moles of NaOH = 0.02512 mol/L × 0.5000 L = 0.01256 mol

Step 5: Calculate the mass of 0.01256 moles of NaOH

The molar mass of NaOH is 40.00 g/mol.

0.01256 mol × 40.00 g/mol = 0.5024 g

Answer:

The pKa of an acid can be determined through titration with a strong base.

Gradually increase the volume of the base, stopping before the equivalence point is reached.

The pKa of the acid is equal to the pH at the midway volume to the equivalence point.

Explanation:

An acid HA dissociates in water as follows:

HA ⇄ H⁺ + A⁻      Ka

So, it produces hydrogen ions (H⁺) and a conjugate base (A⁻). The concentrations of HA, H⁺ and A⁻ at equilibrium determine the constant Ka. The pKa is calculated as:

pKa = -log Ka

The relationship between the pH of the solution and the pKa of the acid is described by the Henderson-Hasselbalch equation:

pH = pKa + log ([A⁻]/[HA])

The pKa can be experimentally determined by acid-base titration, in which a strong base is added to the acid solution. As the base is added, the acid HA is neutralized and the conjugate base A⁻ is formed. Thus, the concentration of the acid ([HA]) increases and the concentration of the conjugate base ([A⁻] decreases. The equivalence point is reached when the total amount of acid is neutralized with the added base. Before reaching the equivalence point, at the halfway point, half of the acid is neutralized and converted into the conjugate base. Thus:

[A-] = [HA] ⇒ log [A-]/[HA] = log 1 = 0 ⇒ pH = pKa

We measure the pH at that point and it is equal to the pKa of the acid.

Answer:

10.5 × 10^5 M

Explanation:

E°cell = E°cathode - E°anode

E°cell = 0.85 - (-0.74) = 1.59 V

From Nernst's equation;

Ecell = E°cell - 0.0592/n log Q

1.499 = 1.59 - 0.0592/6 log [Cr^3+]/6.35x10^-4

1.499 - 1.59 = - 0.0592/6 log [Cr^3+]/6.35x10^-4

-0.091 = -0.00987 log [Cr^3+]/6.35x10^-4

-0.091/ -0.00987 = log [Cr^3+]/6.35x10^-4

9.22 = log [Cr^3+]/6.35x10^-4

Antilog (9.22) = [Cr^3+]/6.35x10^-4

1.66 × 10^9 = [Cr^3+]/6.35x10^-4

[Cr^3+] = 1.66 × 10^9 × 6.35x10^-4

[Cr^3+] = 10.5 × 10^5 M

Answer:

Explanation:

First we convert the given masses into moles, using the compounds' respective molar mass:

Then we multiply each amount by Avogadro's number, to calculate the number of molecules:

The majority of metals are found in ores.

But a few such as copper, gold, platinum, and silver frequently occur in the free state because they do not readily react with other elements.

Answer:

-270.76°C

Explanation:

Given that metal Thallium becomes superconducting below the temperature of 2.39 kelvin i.e. this temperature is critical temperature for Thallium and below critical temperature a metal offers no resistance to the flow of electric current. Also the metal below its critical temperature expels the magnetic field in such a way that they do not penetrate the metal and pass through its surface only.

We have the relation between kelvin scale and degree Celsius scale of temperature measurement as:

[tex]C = K - 273.15[/tex]

[tex]C=2.39-273.15\\ C=-270.76^{o}C[/tex]

Each triglyceride is different from the others on the basis of presence of fatty acids in it.

Triglycerides is a kind of fat and derivative of ester which is formed by the combination of glycerol and three fatty acids.

So in the triglyceride molecule three sub divided parts are present due to the presence of three fatty acids groups and these fatty acids will make difference in each triglyceride molecules.

Hence of fatty acids in triglyceride molecule makes it different from other.

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Answer:

It has different fatty acids.

Explanation:

This is a signature of triglycerides

Answer:

According to the four quantum numbers; magnetic quantum number is the same as angular momentum quantum number. so the answer is 5

Explanation:

for d subshell angular momentum "d" is assigned a value of : m= 2(range from negative to positive i.e, -2 to 2) so we have [ -2, -1 ,0, 1 , 2] which concludes to 5.

Answer:

KBr dissolved in water.

Explanation:

A substance conducts electricity as a result of the presence of mobile ions in the substance.

An ionic substance such as KBr when dissolved in water releases free ions which become charge carriers in solution hence the solution conducts electricity. Solid ionic substances such as solid KBr and solid baking soda do not conduct electricity because the ions are strongly bound to each other in the crystal lattice.

Molecular substances such as sugar and alcohol do not conduct electricity even in solution.

Answer:

Water H2O + SULPHATE OXIDE

Answer:

The material properties of nanostructures are different from the bulk due to the high surface area over volume ratio and possible appearance of quantum effects at the nanoscale. ... Yu; they found that the structural distortions on the quantum dots depend both on the kind of dopant and on the size of the dots.

Explanation:

hope it helps

Answer:

Protein biochemistry is the study of proteins. Protein biochemistry is a scientific field dedicated to the study of proteins, complex chains of amino acids which make up the building blocks of all living organisms.

Explanation:

I hope that helped

Copy and Pasted!

Answer:

Listen to what guy said on top.

Explanation:

polypeptide structures consisting of one or more long chains of amino acids residue.....

or my answer

Answer:

See detailed explanation.

Explanation:

Hello there!

In this case, according to the given description, it turns out possible for us to infer that the second fractionating column on top of the first one will favor the light product, in this case hexane as it has the lowest boiling point and molar mass; in such a way, we can tell the following:

a) The separation between hexane and heptane will be increased as a purer hexane-rich product will be obtained on the top of the second column.

b) Will be increased as well, because the second column will remove more heptane.

c) Also, more pure heptane will be obtained on the bottom of the two columns, yet the most favored yield will be that of hexane.

All of the aforementioned is possible due to the fact that the second column will remove the amount of heptane that could not be removed on the top of the first column by taking the vapor-liquid equilibrium further from the first column's maximum separation, which is known as distillation sequences.

Regards!

Answer:

O B. Alkaline earth metals

Explanation:

Noble gases → 8th column.

Alkali metal → first column.

Halogen → 7th

Answer:

B. Alkaline earth metals

Explanation:

Alkaline-earth metals: The alkaline-earth metals make up Group 2 of the periodic table, from beryllium (Be) through radium (Ra). Each of these elements has two electrons in its outermost energy level, which makes the alkaline earths reactive enough that they're rarely found alone in nature. But they're not as reactive as the alkali metals. Their chemical reactions typically occur more slowly and produce less heat compared to the alkali metals.

Answer:

Depends on molecule.

Explanation:

The number of the polypeptide chains present in the oligomer depends on the molecule. Some molecules have more polypeptide chains whereas some of them have less polypeptide chains. For example, Hemoglobin is a oligomer that consists of four Polypeptide Chains, two of these Polypeptide Chains are α-globin molecules, each comprise of 141 amino acids, and the other two are (β, γ, δ, or ε) globins, each consist of 146 amino acids.

Answer:

3.65 g of cyclohexene

Explanation:

Cyclohexanol + phosphoric acid ----> cyclohexene

The reaction is 1:1 hence the limiting reactant is phosphoric acid.

Hence,

1 mole of phosphoric acid yields 1 mole of cyclohexene

0.0444 moles of phosphoric acid yields 0.0444 moles of cyclohexene

Theoretical yield = number of moles of cyclohexene × molar mass of cyclohexene

Theoretical yield = 0.0444 moles of cyclohexene × 82.143 g/mol

Theoretical yield = 3.65 g of cyclohexene

Answer:

118.06 mL

Explanation:

The neutralization reaction between HBr (acid) and Ba(OH)₂ (base) is the following:

2HBr + Ba(OH)₂ → BaBr₂ + 2H₂O

According to the equation, 2 moles of HBr react with 1 mol Ba(OH)₂. Thus, at the equivalence point the moles of acid and base react completely:

2 moles HBr = 1 mol Ba(OH)₂

We can replace the moles by the product of the molar concentration (M) and volume (V):

2 x (M HBr) x (V HBr) = M Ba(OH)₂ x V Ba(OH)₂

Now, we introduce the data in the equation to calculate the volume in mL of Ba(OH)₂:

V Ba(OH)₂ = (2 x (M HBr) x (V HBr))/M Ba(OH)₂

                 = (2 x 0.311 M x 57.7 mL)/(0.304 M)

                 = 118.06 mL

Therefore, 118 mL of Ba(OH)₂ are needed.

Answer:

Mass CO2 = 3.75 grams

Mass H2O = 2.30 grams

Mass SO2 = 2.73 grams

Explanation:

Step 1: Data given

Density of Liquid ethyl mercaptan, C2H6S = 0.84 g/mL

Volume of ethyl mercaptan = 3.15 mL

Step 2: The reaction

2C2H6S + 9O2 → 4CO2 + 6H2O + 2SO2

Step 3: Calculate mass of ethyl mercaptan

Mass = Volume * density

Mass ethyl mercaptan = 3.15 mL * 0.84 g/mL

Mass ethyl mercaptan = 2.646 grams

Step 4: Calculate moles ethyl mercaptan

Moles = mass / molar mass

Moles ethyl mercaptan = 2.646 grams / 62.13 g/mol

Moles ethyl mercaptan = 0.04259 moles

Step 5: Calculate moles of other products

For 2 moles ethyl mercaptan we need 9 moles O2 to produce 4 moles CO2, 6 moles H2O and 2 moles SO2

For 0.04259 moles we need 0.1917 moles O2 to produce:

2*0.04259 = 0.08518 moles CO2

3*0.04259 = 0.1278 moles H2O

1*0.04259 = 0.04259 moles SO2

Step 6: Calculate mass produced

Mass = moles * molar mass

Mass CO2 = 0.08518 moles * 44.01 g/mol

Mass CO2 = 3.75 grams

Mass H2O = 0.1278 moles * 18.02 g/mol

Mass H2O = 2.30 grams

Mass SO2 = 0.04259 moles * 64.07 g/mol

Mass SO2 = 2.73 grams

Answer:

2.33 mol C

Explanation:

Step 1: Write the balanced generic chemical equation

3 A ⟶ C + 4 D

Step 2: Establish the appropriate molar ratio

According to the balanced equation, the molar ratio of A to C is 3:1.

Step 3: Calculate the number of moles of C produced from 7 moles of A

We will use the previously established molar ratio.

7 mol A × 1 mol C/3 mol A = 2.33 mol C

Answer:

the percent dissociation is  0.69 %

Explanation:

Given the data in the question;

benzoic acid C₆H₅CO₂H

C₆H₅COOH[tex]_{(aq)[/tex]  ⇔ C₆H₅COO[tex]_{-(aq)[/tex] + H[tex]_{+(aq)[/tex]

Ka =  [C₆H₅COO- ][ H+ ] / [ C₆H₅COOH ] = 6.28 × 10⁻⁵

given that it dissociated in a 1.3 M  aqueous solution.

so Initial concentration is;  

[ C₆H₅COOH ] = 1.3

[C₆H₅COO- ] = 0

[ H+ ] = 0

Change in concentration

[ C₆H₅COOH ] = -x

[C₆H₅COO- ] = +x

[ H+ ] = +x

Concentration equilibrium

[ C₆H₅COOH ] = 1.3 - x

[C₆H₅COO- ] = +x

[ H+ ] = +x

Hence,

x² / ( 1.3 - x ) = 6.28 × 10⁻⁵

6.28 × 10⁻⁵( 1.3 - x ) = x²

8.164 × 10⁻⁵ - 6.28 × 10⁻⁵x = x²

x² + 6.28 × 10⁻⁵x - 8.164 × 10⁻⁵ = 0

solve for x

ax² + bx - c = 0

x = [ -b ± √( b² - 4ac ) ] / [ 2a ]

we substitute  

x = [ -6.28 × 10⁻⁵ ± √( (6.28 × 10⁻⁵)² - (4 × 1 × -8.164 × 10⁻⁵ ) ) ] / [ 2 × 1 ]  

x = [ -6.28 × 10⁻⁵ ± 0.01807 ] / [ 2]

x = [ -6.28 × 10⁻⁵ - 0.01807 ] / [ 2]  or [ -6.28 × 10⁻⁵ + 0.01807 ] / [ 2]

x = -0.0090664 or 0.0090036

so x = 0.0090036

hence

[ H+ ] = +x = 0.0090036 M

[C₆H₅COO- ] = +x = 0.0090036 M

Initial concentration of [ C₆H₅COOH ] = 1.3 M

concentration of C₆H₅COOH dissociated = 0.0090036 M

percent dissociation of C₆H₅COOH will be;

⇒ ( 0.0090036 M / 1.3 M ) × 100 = 0.69 %

Therefore, the percent dissociation is  0.69 %

Answer:

Explanation:

hope it heloed

Answer:

That is, the atom is a solid and indivisible mass. However, the fenomenom by which an iron atom emits particles when it is struck by light (known as the photoelectric effect) can not be explaind by this indivisible atom model.

Answer:

Yes. The solution would be optically active.

Explanation:

Diastereomer are defined as the image that is non mirror and non -identical. It is made up of two stereoisomers. They are formed when the two stereoisomers or more than two stereoisomers of the compound have the same configuration at the equivalent stereocenters.

In the given context, as the product given is a diastereomeric mixture, the product would have an optical activity in total.

So the answer is Yes.