Draw the structure of beta-D-idose in its pyranose form.

Answer:

Wave A has a higher frequency because it has a shorter wavelength.

Explanation:

The frequency of a wave and the wave length are related by the following equation:

Velocity (v) = wave length (λ) x frequency (f)

v = λf

If we make frequency (f) the subject of the above equation, we will have:

f = v/λ

Let the velocity (v) be constant.

f = v/λ

f & 1/λ

From the equation above,

We can see that the frequency (f) is inversely proportional to the wavelength (λ).

This implies that a wave with a high frequency, will have a short wavelength and a wave with a short frequency will have a longer wavelength.

Now considering wave A and B in the diagram above,

Wave A will have a higher frequency because it has a shorter wavelength as explained above.

Answer:

it is the second option

Explanation:

Answer:

1-remain the same

2- remain the same

3-decrease

--------------------------

- decrease

- As the temperature is decreased, the reaction shifts from left to right. The product concentrations increase, and the reactant concentrations decrease. This corresponds to an increase in Kc.

--------------------------------

1- decrease

2-increase

3-decrease

4-remain the same

5-decrease

Explanation:

According to Le Chateliers principle, an increase in the volume of a gaseous system at equilibrium will shift the equilibrium position towards the side in which there are less volumes. Hence the answers written. When there is no change in volume, the number of moles of products remain the same.

-------------------------------

For an exothermic reaction, increasing the temperature shifts the equilibrium to the lefthand side.

When temperature is decreased, the equilibrium position will shift towards the right according to Le Chateliers principle

---------------------

Addition of a catalyst aids the reaction in which CO is consumed to proceed faster hence CO decreases in the system.

Since the reaction is exothermic, according to Le Chateliers principle, when the temperature is increased, the equilibrium position shifts towards the lefthand side and more CO is now present in the system.

When the pressure of the system is increased, the equilibrium position will shift towards the right hand side and more CO is converted to products hence its concentration in the system decreases.

Addition of argon gas has no effect on the equilibrium position since it does not participate in the reaction. However, addition of the reactant gases increases the rate of reaction and shifts the equilibrium position towards the right hand side thus decreasing the concentration of CO in the system.

Answer:

0.373 M

Explanation:

The balanced equation for the reaction is given below:

HC2H3O2 + NaOH —> NaC2H3O2 + H2O

From the balanced equation above, the following were obtained:

Mole ratio of the acid, HC2H3O2 (nA) = 1

Mole ratio of the base, NaOH (nB) = 1

Next, we shall write out the data obtained from the question. This include:

Volume of base, NaOH (Vb) = 32.17 mL

Molarity of base, NaOH (Mb) = 0.116 M

Volume of acid, HC2H3O2 (Va) = 10 mL

Molarity of acid, HC2H3O2 (Ma) =..?

The molarity of the acid solution can be obtained as follow:

MaVa/MbVb = nA/nB

Ma x 10 / 0.116 x 32.17 = 1

Cross multiply

Ma x 10 = 0.116 x 32.17

Divide both side by 10

Ma = (0.116 x 32.17) /10

Ma = 0.373 M

Therefore, the concentration of the acetic acid is 0.373 M.

Answer:

Group 12

Explanation:

Group 12 transition metals are diamagnetic. They behave properties that distinguish them. They naturally have twelve electrons hence their outermost shell is fully filled.

Transition metals have high densities which increases down the group. However, the increase in density of transition elements of group 12 varies with temperature at a rate that is quite different from other transition elements. Hence the differences in the value of melting points and density changes by only a very small amount as you come down group 12 compared to other groups of transition elements.

Answer:

6

Explanation:

Alkanes undergo substitution reaction so the number of replacement reaction hydrogen is 6

Answer:

Explanation:

[tex]2x^2+10x-48\\=2\left(x^2+5x-24\right)\\x^2+5x-24\\=\left(x^2-3x\right)+\left(8x-24\right)\\=x\left(x-3\right)+8\left(x-3\right)\\=\left(x-3\right)\left(x+8\right)\\=2\left(x-3\right)\left(x+8\right)\\2\left(x-3\right)\left(x+8\right)=0\\x-3=0\\x = 0+3\\x = 3\\x+8=0\\x+8-8=0-8\\x=-8\\x=3,\:x=-8[/tex]

Answer:

Explanation:

1 . The strongest force observed at the surface of glass is:__DIPOLE______

2. . Water is__POLAR_________ and interacts, generating adhesive interactions with the only weak dispersion strong hydrogen bonding polar glass.

3 . Hexane is_NON-POLAR _______ and interacts, generating__ONLY WEAK __________ adhesive interactions with the glass.

Answer:

The concentration takes 25.360 seconds to decrease to one-ninth of its initial value.

Explanation:

The decomposition of the compound has an exponential behavior and process can be represented by this linear first-order differential equation:

[tex]\frac{dc}{dt} = -\frac{1}{\tau}\cdot c(t)[/tex]

Where:

[tex]\tau[/tex] - Time constant, measured in seconds.

[tex]c(t)[/tex] - Concentration of the compound as a function of time.

The solution of the differential equation is:

[tex]c(t) = c_{o} \cdot e^{-\frac{t}{\tau} }[/tex]

Where [tex]c_{o}[/tex] is the initial concentration of the compound.

The time is now cleared in the result obtained previously:

[tex]\ln \frac{c(t)}{c_{o}} = -\frac{t}{\tau}[/tex]

[tex]t = -\tau \cdot \ln \frac{c(t)}{c_{o}}[/tex]

Time constant as a function of half-life is:

[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex]

Where [tex]t_{1/2}[/tex] is the half-life of the composite decomposition, measured in seconds.

If [tex]t_{1/2} = 8\,s[/tex], then:

[tex]\tau = \frac{8\,s}{\ln 2}[/tex]

[tex]\tau \approx 11.542\,s[/tex]

And lastly, given that [tex]\frac{c(t)}{c_{o}} = \frac{1}{9}[/tex] and [tex]\tau \approx 11.542\,s[/tex], the time taken for the concentration to decrease to one-ninth of its initial value is:

[tex]t = -(11.542\,s)\cdot \ln\frac{1}{9}[/tex]

[tex]t \approx 25.360\,s[/tex]

The concentration takes 25.360 seconds to decrease to one-ninth of its initial value.

Answer:

a. increase

Explanation:

Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst, which is not consumed in the catalyzed reaction.

By default, catalysts exists to speed up the rate of reactions. Increasing the amount of catalysts means that there would be an increase in the rate of reaction. The correct option is A.

The given question is incomplete. The complete question is :

A chemist prepares a solution of barium acetate by measuring out 32 g of barium acetate into a 350 ml volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's barium acetate solution. Round your answer to significant digits.

Answer:  The concentration of barium acetate solution is 0.375 mol/L

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in ml

moles of [tex]Ba(CH_3COO)_2[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{32g}{255g/mol}=0.125mol[/tex]

Now put all the given values in the formula of molality, we get

[tex]Molarity=\frac{0.125\times 1000}{350ml}[/tex]

[tex]Molarity=0.357M[/tex]

Therefore, the concentration of solution is 0.375 mol/L

Answer:

b. Binary compounds of carbon and hydrogen

Explanation:

Before proceeding, Hydrocarbons refers to organic chemical compounds composed exclusively of hydrogen and carbon atoms. This means the only elements present in an hydrocarbon are;

- Carbon

- Hydrogen

Looking through the options;

- Option A: This is wrong because the hydroxyl group contains oxygen and hydrocarbons contain only hydrogen and carbon.

- option B: This is correct. Binary compounds refers to compounds with just two elements.

- option C: This is wrong because water contains oxygen and hydrocarbons contain only hydrogen and carbon.

- option D: Carbon atoms can contain other elements so this option is wrong.

- option E: This also wrong because we had already gotten the correct option.

Answer:

Keq = 0.217

Explanation:

Let's determine the equilibrium reaction.

In gaseous state, water vapor can be decomposed to hydrogen and oxygen and this is a reversible reaction.

2H₂(g)  + O₂(g)  ⇄  2H₂O (g)         Keq

Let's make the expression for the equilibrium constant

Products / Reactants

We elevate the concentrations, to the stoichiometry coefficients.

Keq = [H₂O]² / [O₂] . [H₂]²

Keq = 0.250² / 0.8 . 0.6² =  0.217

Answer:

pH = 4.79

Explanation:

The pH of the acetic buffer can be determined using H-H equation:

pH = pKa + log [A⁻] / [HA]

Where pKa is -logKa = 4.76

pH = 4.76 + log [sodium Acetate] / [Acetic Acid]

Where [] can be taken as moles of each specie.

Thus, to find pH of the buffer we need to calculate molesof acetic acid and sodium acetate.

Initial moles:

Initial moles of acetic acid and sodium acetate are:

500mL = 0.500L ₓ (0.60moles / L) = 0.30 moles of both acetic acid and sodium acetate

Moles after reaction:

Now, 0.010 moles of NaOH are added to the buffer reacting with acetic acid, CH₃COOH, producing more acetate ion, as follows:

NaOH + CH₃COOH → CH₃COO⁻ + H₂O

That means after reaction moles of both species are:

Acetic acid: 0.30mol - 0.010mol (Moles that react) = 0.29 moles

Acetate: 0.30mol + 0.010mol (Moles produced) = 0.31 moles

Replacing in H-H equation:

pH = 4.76 + log [0.31] / [0.29]

Answer: 3. Molecules that are improperly oriented during collision will not react.

Explanation:

According to the collision theory , the number of collisions that take place per unit volume of the reaction mixture is called collision frequency. The effective collisions are ones which result into the formation of products.

It depends on two factors:-

1. Energy factor:  For collision to be effective,  the colliding molecules must have energy more than a particular value called as threshold energy.

2. Orientation factor: Also the colliding molecules must have proper orientation at the time of collision to result into formation of products.

Thus not all collisions between reactant molecules lead to reaction because molecules that are improperly oriented during collision will not react.

Answer:

Strong intermolecular forces:  an increase in viscosity of the liquid, increase in surface tension, decrease in vapor pressure, and an increase in the boiling point.

Weak intermolecular forces: a decrease in viscosity, a decrease in surface tension, an increase in vapor pressure and an increase in boiling point.

Explanation:

Intermolecular forces are forces of attraction or repulsion between neighboring molecules in a substance. These intermolecular forces inclde dispersion forces, dipole-dipole interactions, hydrogen bonding, and ion-dipole forces.

The strength of the intermolecular forces in a liquid usually affects the various properties of the liquid such as viscosity, surface tension, vapour pressure and boiling point.

Strong intermolecular forces in a liquid results in the following; an increase in viscosity of the liquid, increase in surface tension, decrease in vapor pressure, and an increase in the boiling point of the liquid.

Weak intermolecular forces in a liquid results in the following; a decrease in viscosity, a decrease in surface tension, an increase in vapor pressure and an increase in boiling point of that liquid.

Strong intermolecular force is defined as the increase in viscosity of the liquid, increase in surface tension, decrease in vapor pressure, and an increase in the boiling point while  weak intermolecular forces define as the decrease in viscosity, a decrease in surface tension, an increase in vapor pressure, and an increase in boiling point.

Intermolecular forces are forces of attraction or repulsion between neighboring molecules in a substance. These intermolecular forces include as follows:-

Strong intermolecular forces in a liquid result in the following; an increase in viscosity of the liquid, increase in surface tension, decrease in vapor pressure, and an increase in the boiling point of the liquid.

Weak intermolecular forces in a liquid result in the following; a decrease in viscosity, a decrease in surface tension, an increase in vapor pressure, and an increase in the boiling point of that liquid.

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Answer:

It will take 6486.92 minutes  for [H2O2] to fall from 0.95 M to 0.33 M

Explanation:

The order of reaction is defined as the sum of the powers of the concentration terms in the equation. Order of a reaction is given by the number of atoms or molecule whose concentration change during the reaction and determine the rate of reaction.

In first order reaction;

[tex]In \dfrac{a}{a_o-x}= k_1 t[/tex]

where;

a = concentration at time t

[tex]a_o[/tex] = initial concentration

and k = constant.

[tex]In (\dfrac{0.33}{0.95})= -1.63 \times 10^{-4} \times t[/tex]

[tex]-1.05736933 = -1.63 \times 10^{-4} \times t[/tex]

[tex]t = \dfrac{-1.05736933}{ -1.63 \times 10^{-4} }[/tex]

t = 6486.92 minutes

Answer:

0.3 mol

Explanation:

Assuming HCl is in excess and Zn is the limiting reagent,

from the balanced equation, we can see the mole ratio of Zn:H2 = 1:1,

which means, each mole of zinc reacted gives 1 mole of H2.

So, if 0.30 mol Zn is added, the no. of moles of H2 produced will also be 0.3 mol, since the ratio is 1:1.

Answer:

Option A

Explanation:

Silicon (Obtained from Sand (SiO2)) is the element that is primarily used in appliances to make electronic chips.

Answer:

A. Silicon (Si)

Explanation:

Silicon (Si) is primarily used as a semiconductor material to make electronic chips.

Answer:

The drawing that represents the result of placing all three liquids into the same graduated cylinder will have the liquid arranged one on top of the other from top to bottom in the order of A, C, B.

Explanation:

The image with the options is not provided in this question, but I can answer this fairly so that you can pick from the question, the correct drawing.

We know that two or more immiscible liquids contained together in a container will always separate in the order of their density from top to bottom, with the densest at the bottom, and the least densest at the top. In this case, liquid A is the least densest, and liquid B is the densest. Liquid A will stay on top, and liquid B will be at the bottom. Liquid C will be in between liquid A and liquid B.

Answer:

4NH₃(g)  + 5O₂(g)  →  4NO(g)  +  6H₂O

2NO(g) + O₂(g) → 2 NO₂

Explanation:

First of all, we need to consider the reaction for production of ammonia. In this reaction we have as reactants, nitrogen and hydroge.

3H₂ (g) +  N₂(g)  →  2NH₃ (g)

Afterwards, ammonia reacts to oxygen, to produce NO and H₂O

The equation for the process will be:

4NH₃(g)  + 5O₂(g)  →  4NO(g)  +  6H₂O

Then, we take the nitric oxide to make it react, to produce NO₂, in order to produce nitric acid, for the final reaction:

2NO(g) + O₂(g) → 2 NO₂

3NO₂(g) + H₂O(g) → 2 HNO₃ (g) + NO(g)

Answer:

Ethyl cinnamate

Explanation:

For this question, we have to start with the IR info. If we have a peak at 1710 this indicates the presence of a carbonyl group in the molecule (C=O). Additionally, if we calculate the I.H.D (index of hydrogen deficiency), we will have a value of "6". We already know that we have a C=O group, so, this counts for 1 of the 6 additionally, we can have a benzene ring so, this counts for 4, so far we have 5. Finally, we will have a double bond outside of benzene and we will have a total of 6, so:

Benzene: 4

Carbonyl group: 1

Double bond: 1

For a total of six (that fits with the I.H.D calculation). So, so far we know that we have a benzene ring, a double bond, and a carbonyl group. In the formula we have 2 oxygens, therefore we can have a carboxylic acid or an ester. In this case, the IR info doesn't give any additional info, so our best option is the ester group.

The 1H NMR info give is:

Signal A= 1.3 (3 H, triplet)

Signal B= 4.3 (2 H, quartet)

Singal C= 6.5 (1 H, doublet)

Signal D= 7.4-7.6 (5 H, multiplet)

Signal E= 7.7 (1 H, doublet)

The molecule that fits with this NMH spectrum and the info given by the I.H.D is "ethyl cinnamate".

See figure 1

I hope it helps!

Answer:

The possible solution is to balance the rate of water removal from the well to the rate of natural recharge of the well from its underground aquifer.

Explanation:

A well is an excavation in the earth, made with the aim of extracting water from the aquifers. The water from a well can be drawn up by the means of a pump, containers, such as buckets, or by hand. Aquifers can also be recharged through a well.

Well draw down occurs when water from the well is drained faster than it is naturally recharged from the aquifer. This can be as a result of over pumping, extended drought, among other factors. The use of the high-powered motor in this case, for pumping, might be the possible cause of the well drying up. The situation might have resulted from the pump drawing out water from the well at a rate tat exceeds the rate at which it is recharged naturally, causing the well water to start drying up. There's also a possibility that the well is pumped indiscriminately, possibly leading to wastage of water.

The solution to this problem is to give the well a time duration for it to recharge itself. Then, the rate of recharges should be calculated and determined by an hydrologist. When all these is done, a pump with a motor power that does not exceed the calculated recharge rate should be used in place of the high-powered motor. Also, water usage should be brought to the minimum level to prevent unnecessary pumping due to excessive, wasteful use of water.

Answer:

An alkyl halide can undergo SN2 reaction with an amine

Explanation:

The displacement of a bromine atom by an an amine (step 2---> 3) in the reaction sequence is an example of an SN2 reaction in which the amine is the nucleophile.

The nitrogen atom of the amine which bears a lone pair of electrons functions as the nucleophile and attacks the electrophilic carbon atom of the alkyl halide displacing the bromide and creating a new Carbon-Nitrogen bond. An ammonium intermediate is immediately formed and the reaction is completed by the abstraction of a hydrogen by a base (such as excess amine present in the system).

This reaction is slower with t-BuNH2 because of steric hindrance and steric crowding in the transition state. SN2 reactions are faster with methylamine where the alkyl carbon is easily accessible.

The detailed mechanism of this reaction has been attached to this answer.

Answer:

[C₆H₅NH₃⁺] = 0.0399 M

Explanation:

This excersise can be easily solved by the Henderson Hasselbach equation

C₆H₅NH₃Cl → C₆H₅NH₃⁺  + Cl⁻

pOH = pKb + log (salt/base)

As we have value of pH, we need to determine the pOH

14 - pH = pOH

pOH = 8.43  (14 - 5.57)

Now we replace data:

pOH = pKb + log ( C₆H₅NH₃⁺/  C₆H₅NH₂ )

8.43 = 9.13 + log (  C₆H₅NH₃⁺ / 0.2 )

-0.7 = log (  C₆H₅NH₃⁺ / 0.2 )

10⁻⁰'⁷ = C₆H₅NH₃⁺ / 0.2

0.19952 = C₆H₅NH₃⁺ / 0.2

C₆H₅NH₃⁺ = 0.19952 . 0.2  = 0.0399 M

Answer:

PhCH2CH2COOH

Explanation:

This is a reaction of PhCH2CH2Br with KCN in the presence of H3O^+. The reaction first leads to the formation of PhCH2CH2CN.

We must recall that part of the properties of nitriles is that they can be converted to carboxylic acids in the presence of H3O^+. This is a common synthetic route for carboxylic acids.

Therefore, when the PhCH2CH2CN is now further reacted with H3O^+, the carboxylic acid PhCH2CH2COOH is formed as the major organic product of the reaction, hence the answer given above.

Answer:

Molar mass of the gas is 0.0961 g/mol

Explanation:

The effusion rate of an unknown gas = 11.1 min

rate of [tex]H_{2}[/tex] effusion = 2.42 min

molar mass of hydrogen = 1 x 2 = 2 g/m

molar mas of unknown gas = ?

From Graham's law of diffusion and effusion, the rate of effusion and diffusion is inversely proportional to the square root of its molar mass.

from

[tex]\frac{R_{g} }{R_{h} }[/tex] = [tex]\sqrt{\frac{M_{h} }{M_{g} } }[/tex]

where

[tex]R_{h}[/tex] = rate of effusion of hydrogen gas

[tex]R_{g}[/tex] = rate of effusion of unknown gas

[tex]M_{h}[/tex] = molar mass of H2 gas

[tex]M_{g}[/tex] = molar mass of unknown gas

substituting values, we have

[tex]\frac{11.1 }{2.42 }[/tex] = [tex]\sqrt{\frac{2 }{M_{g} } }[/tex]

4.587 = [tex]\sqrt{\frac{2 }{M_{g} } }[/tex]

[tex]\sqrt{M_{g} }[/tex] = [tex]\sqrt{2}[/tex]/4.587

[tex]\sqrt{M_{g} }[/tex] = 0.31

[tex]M_{g}[/tex] = [tex]0.31^{2}[/tex] = 0.0961 g/mol

The molar mass of the unknown gas will be "0.0961 g/mol".

Given:

Effusion rate of unknown gas,

Effusion rate of [tex]H_2[/tex],

Molar mass of hydrogen,

              [tex]= 2 \ g/m[/tex]

According to the Graham's law, we get

→    [tex]\frac{R_g}{R_h} = \sqrt{\frac{M_h}{M_g} }[/tex]

By substituting the values, we get

→   [tex]\frac{11.1}{2.42} = \sqrt{\frac{2}{M_g} }[/tex]

→ [tex]4.587=\sqrt{\frac{2}{M_g} }[/tex]

→ [tex]\sqrt{M_g} = \sqrt{\frac{2}{4.587} }[/tex]

   [tex]\sqrt{M_g} = 0.31[/tex]

       [tex]M_g = 0.0961 \ g/mol[/tex]

Thus the above solution is right.          

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Answer:

Replacing 3 of the H of LiALH4 with OR groups make it a more reactive reducing agents than NaBH4

Explanation:

LiAlH4 and NaBH4 are two well known reducing agents in organic chemistry. These two reducing agents function by transfer of hydrogen to the substrate.

If the hydrogen atoms in LiAlH4 are replaced by the -OR moiety, the new compound will be far less reducing than NaBH4 because the hydrogen atoms necessary to effect the reduction has been removed. Thus, the new compound containing -OR moiety can never be more reducing than NaBH4. This implies that the statement written in the answer is false as written.

Answer:

% yield of the student's experiment is

[tex]\frac{0.34}{0.60}[/tex] ˣ 100 = 56.67%

Explanation:

given

volume of acetone= 43.8 mL

molar weight of acetone = 58.08 g/mol

density of acetone = 0.791 g/mL

A student mixes 43.8 mL of acetone (58.08 g/mol, 0.791 g/mL)

43.8 mL = 43.8mL × 0.791g/mL

= 34.6458g ≈34.65g

1 mole of acetone = 58.08g

∴34.65g = 34.65g/58.08g

= 0.60mol

molecular weight of the product 1,5-diphenylpenta-1,4-dien-3-one = 234.29 g/mol

mole = mass/ molar weight

mole = 79.4g/ 234.29g/mol

mole(n) = 0.3389mol ≈ 0.34mol

1 mole of acetone will produce 1 mole of the product

∴0.60mol of acetone will produce 0.60mol of the product

but we get 0.34mol of the product

∴ % yield of the student's experiment is

[tex]\frac{0.34}{0.60}[/tex] ˣ 100 = 56.67%

A heterogeneous mixture​

Answer:

[tex]w/v\%=3.02\frac{g}{mL} \%[/tex]

Explanation:

Hello,

In this case, we first define the formula for the calculation of weight/volume percentage considering cobalt (II) fluoride as the solute, water the solvent and the both of them as the solution:

[tex]w/v\%=\frac{mass_{solute}}{V_{solution}}*100\%[/tex]

In such a way, since the mass of the solute is given as 6.04 g and the final volume of the solution 200 mL, the weight/volume percentage turns out:

[tex]w/v\%=\frac{6.04g}{200mL}*100\%\\\\w/v\%=3.02\frac{g}{mL} \%[/tex]

Regards.