1) Why does polysubstitution frequently occur with Friedel-Crafts alkylation but not with Friedel-Crafts acylation?2) If Benzene is reacted with t-butyl chloride, why is the chief disubstituted product the para rather than ortho isomer?

Answer:

Mass of the unknown acid is 4.0g

Explanation:

The determine the molar mass of the unknown acid, the steps below can be followed

Firstly, determine the concentration of the acid, the formula below can be used;

ConcA × Va/ConcB × Vb = Na/Nb

Where ConcA is the concentration of the unknown acid

ConcB is the concentration of the NaOH base

Va is the volume of acid and Vb is the volume of base

Since, the titration was said to have reached an equivalent point, it means the number of moles of the acid (Na) was equal to the number of moles of the base (Nb) and thus both will be assumed to be 1

Thus

ConcA × 250/0.13 × 6.6 = 1/1

ConcA = 0.13 × 6.6/250

ConcA = 0.003432M

Then, determine the actual number of moles (n) of the unknown acid used,

ConcA = no of moles of acid/volume of acid (in dm³ or L)

To convert mL to L, we divide by 1000

Hence, 250ml = 0.25L

0.003432 = n/0.25

n = 0.003432 × 0.25

n = 0.01373 moles

To determine the molar mass;

n = mass/molar mass

The mass was given in the question to be 0.055g

Thus

0.01373 = 0.055/molar mass

molar mass = 0.055/0.01373

molar mass = 4.0g

Answer: The glass cup falling

Explanation:

It didnt change chemically, only its physical appearance

Answer:

I think it's A and D

Explanation:

I'm not sure if it's right

Answer:

The answer is B and D

Explanation:

trust fr

Answer:D

Explanation: in molecular solids, one factor that determines the strength of intermolecular forces is the mass of the molecules. Since all of these compounds only contain hydrogen and carbon we don’t have to worry about their polarities as they are all the same. Inter molecular forces tend to be stronger when the molecular weight is greater since paraffin wax is the only solid at room temperature it has the highest melting point

Answer: Your Answer Is D. Paraffin wax

Explanation:Hope This Helps!

We know,

[tex]\Delta H_{I_2(g)}=62.438\ KJ/mol\\\\\Delta H_{Cl_2(g)}= 0.0\ KJ/mol\\\\\Delta H_{ICl(g)}=17.78\ KJ/mol[/tex]

For given reaction, [tex]I_2(g)+Cl_2(g)\ -->\ 2ICl(g)[/tex]

[tex]\Delta H_{rxn}=2\Delta H_{ICl(g)}-\Delta H_{I_2(g)}-\Delta H_{Cl_2(g)}\\\\\Delta H_{rxn}=2(17.78)-0-62.438\ KJ/mol\\\\\Delta H_{rxn}=-26.878\ KJ/mol[/tex]

For , 2.41 moles of [tex]I_2[/tex] :

[tex]\Delta H_{rxn}=2.41\times (-26.878)\ KJ\\\\\Delta H_{rxn}=-64.78\ KJ[/tex]

We know :

[tex]\Delta S = -\dfrac{\Delta H_{rxn}}{T}\\\\\Delta S = -\dfrac{-64.78}{298}\ KJ/K\\\\\Delta S =-0.21738 \ KJ/K\\\\\Delta S=-217.38\ J/K[/tex]

Hence, this is the required solution.

Answer:  a

Energy that is stored or released during a chemical reaction

Explanation: a battery has chemical energy when u but in something that u can power with batteries it starts a chemical reaction.

Hope I helped :)

Explanation:

Chemical energy

Chemical energy is energy stored in the bonds of chemical compounds, like atoms and molecules. This energy is released when a chemical reaction takes place.

Usually, once chemical energy has been released from a substance, that substance is transformed into a completely new substance.

Answer:

The wood sample has an age of approximately 22800 years.

Explanation:

The Becquerel ([tex]Bq[/tex]) is a SI unit which describes radioactive activity related to decay of radioactive isotopes, which is equivalent to [tex]\frac{1}{s}[/tex]. The decay of radioactive isotope is described by the following ordinary differential equation:

[tex]\frac{dN}{dt} = -\frac{N}{\tau}[/tex] (Eq. 1)

Where:

[tex]\frac{dN}{dt}[/tex] - Disintegration rate, measured in [tex]\frac{1}{s}[/tex].

[tex]N[/tex] - Amount of remaining radioactive nuclei, dimensionless.

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

By integration the solution of this differential equation is obtained:

[tex]\int {\frac{dN}{N} } = -\frac{t}{\tau}\int dt[/tex]

[tex]\ln N = -\frac{t}{\tau} + C[/tex]

[tex]N(t) = N_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)

Let [tex]N_{1}[/tex] and [tex]N_{2}[/tex] different disintegration rates for Carbon-14 samples, so that:

[tex]N_{1} = N_{o} \cdot e^{-\frac{t_{1}}{\tau} }[/tex] (Eq. 3)

[tex]N_{2} = N_{o}\cdot e^{-\frac{t_{2}}{\tau} }[/tex] (Eq. 4)

If we divide (Eq. 4) by (Eq. 3), then:

[tex]\frac{N_{2}}{N_{1}} = \frac{N_{o}\cdot e^{-\frac{t_{2}}{\tau} }}{N_{o}\cdot e^{-\frac{t_{1}}{\tau} }}[/tex]

[tex]\frac{N_{2}}{N_{1}} = e^{-\frac{1}{\tau}\cdot (t_{2}-t_{1}) }[/tex] (Eq. 5)

If [tex]\Delta t = t_{2}-t_{1}[/tex], we proceed to clear that variable:

[tex]\ln \frac{N_{2}}{N_{1}} = -\frac{1}{\tau}\cdot \Delta t[/tex]

[tex]\Delta t = -\tau\cdot \ln \frac{N_{2}}{N_{1}}[/tex] (Eq. 6)

Time constant is also a function of half-life ([tex]t_{1/2}[/tex]), measured in seconds:

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

If [tex]t_{1/2} = 1.798\times 10^{11}\,s[/tex], [tex]N_{1} = 14\,\frac{1}{s}[/tex] and [tex]N_{2} = 0.875\,\frac{1}{s}[/tex],  the age of the wood sample is:

[tex]\tau = \frac{1.798\times 10^{11}\,s}{\ln 2}[/tex]

[tex]\tau = 2.594\times 10^{11}\,s[/tex]

[tex]\Delta t = -(2.594\times 10^{11}\,s)\cdot \ln \left(\frac{0.875\,\frac{1}{s} }{14\,\frac{1}{s} } \right)[/tex]

[tex]\Delta t \approx 7.192\times 10^{11}\,s[/tex]

[tex]\Delta t \approx 22805.682\,yr[/tex]

The wood sample has an age of approximately 22800 years.

Answer:

NaCl(aq)

Explanation:

Nacl(aq) is an electrolyte when it melts and it conducts electricity. This is due to the fact that when it is in solution, it dissociates to be Na+ and Cl-. These ions are conductors of electricity. It conducts electricity because of the movements and also the discharge of ions. CH3OH(aq) is not a conductor of electricity therefore the first option is the answer.

Answer:

a)Weight of Y extracted from water in single extraction = 67.2 g

b) Total weight of Y extracted from water in two successive extractions = 70.9 g

Explanation:

Distribution coefficient, Kd = Cs / Cm

where Cs  is concentration of solute in methylene chloride; Cm is concentration of solute in water

a) Let x g of solute Y be extracted into methylene chloride

72.0 - x g of Y will be left in water

Kd = (x/180 mL of methylene chloride) / (72.0 - x/180 mL of water) = 14

14 = 180 * x / 180 * 72.0 - x

x = 14(72.0 - x)

x = 1008 - 14x

15x = 1008

x = 1008/15

x = 67.2 g

Weight of Y extracted from water in single extraction = 67.2 g

b) First extraction: Let x g of solute Y be extracted into methylene chloride

72.0 - x g of Y will be left in water

14 = x/90 / 72.0 - x/180

14 = 180x/ 90(72.0 - x)

14 = 2x/ 72.0 - x

2x = 14(72.0 - x)

2x =  1008 - 14x

16x = 1008

x = 63.0 g

Second extraction: Amount of solute left in water after first extraction = 72 - 63 = 9.0 g

Let x g of solute Y be extracted into methylene chloride

9.0 - x g of Y will be left in water

14 = x/90 / 9.0 - x/180

14 = 180x/ 90(9.0 - x)

14 = 2x/ 9.0 - x

2x = 14(9.0 - x)

2x =  126 - 14x

16x = 126

x = 7.90 g

Total weight of Y extracted = (63 + 7.90) g

Total weight of Y extracted from water in two successive extractions = 70.9 g

a) The Weight of Y extracted from water in single extraction is 67.2 g

b) The Total weight of Y extracted from water in two successive extractions should be 70.9 g

Here

The distribution coefficient, Kd should be

= Cs / Cm

where

Cs  should be a concentration of solute in methylene chloride;

Cm should be a concentration of solute in water

a) Let  us assume x g of solute Y that should be extracted into methylene chloride

So,

72.0 - x g of Y will be left in water

And, now

Kd = (x/180 mL of methylene chloride) / (72.0 - x/180 mL of water) = 14

So,

14 = 180 * x / 180 * 72.0 - x

x = 14(72.0 - x)

x = 1008 - 14x

15x = 1008

x = 1008/15

x = 67.2 g

b)

Now First extraction:

Let x g of solute Y be extracted into methylene chloride

So,

72.0 - x g of Y will be left in water

14 = x/90 / 72.0 - x/180

14 = 180x/ 90(72.0 - x)

14 = 2x/ 72.0 - x

2x = 14(72.0 - x)

2x =  1008 - 14x

16x = 1008

x = 63.0 g

Second extraction:

Amount of solute left in the water after the first extraction that should be

= 72 - 63

= 9.0 g

Now

Let x g of solute Y be extracted into methylene chloride

9.0 - x g of Y will be left in water

14 = x/90 / 9.0 - x/180

14 = 180x/ 90(9.0 - x)

14 = 2x/ 9.0 - x

2x = 14(9.0 - x)

2x =  126 - 14x

16x = 126

x = 7.90 g

Total weight of Y extracted = (63 + 7.90) g

= 70.9g

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Answer:

I'm pretty sure its d.

Explanation:

because a gbular protein is a protein that is round in shape, and a fibrous is a long a thin shaped protein. Which those are two kinds of proteins.

Answer:

A family is a vertical column .

The elements in a family have similar chemical properties.

Answer:

Explanation:

Iodine is the most flexible of the atoms in Group 17 of the periodic table. It can have more than 1 charge, especially when combined with oxygen. The answer that you are expected to give, I think is C. Iodine's dominant charge is - 1

Answer:

a.  very acidic

Explanation:

A solution with a pH of 1.6 would be described as a very acidic solution.

The pH scale is a convenient scale for expressing the level of acidity or alkalinity of aqueous solutions.

The scale ranges from 1 to 14 in which case 1 is the lower limit and 14 the upper limit.  

Answer:

Geology is the world... Elements make it up

Explanation:

Answer:

A lot of the elements are found in rocks, minerals, and well since they are elements make they make up everything on earth.

Explanation:

Answer:

the bike will go down 5 N

Answer:

Explanation:

The equation must be balanced on both sides to show the law of conservation of mass. So, as long as it is equaled, the law is shown.

Answer:

I literally got this from google.

Explanation:

In ordinary air, sodium metal reacts to form a sodium hydroxide film, which can rapidly absorb carbon dioxide from the air, forming sodium bicarbonate. ... In a comparatively dry atmosphere, sodium burns quietly, giving off a dense white caustic smoke, which can cause choking and coughing.

Happy almost Halloween! :)

Answer:

The answer is "Option a".

Explanation:

Multiply the mass of the solutions by 3.17% to get the mass of [tex]BaCl_2[/tex]:

[tex]\to 427 \ g \times 0.0317 = 13.56\ g[/tex]

Divide this mass with BaCl2's molecular concentration to acquire the mole ratio:  

[tex]molar mass = 208.24 \frac{g}{mol}\\\\moles = \frac{13.56}{208.24} = 0.065 \ moles \\\\[/tex]

                       [tex]= 6.5 \times 10^{-2} \ moles[/tex]

A 427 g sample is 3.17% by mass barium chloride contains 6.5 × 10⁻² moles of BaCl₂.

A 427 g sample is 3.17% by mass barium chloride, that is, there are 3.17 g of barium chloride per 100 g of sample.

The mass of barium chloride in 427 g of the sample is:

[tex]427gSample \times \frac{3.17gBaCl_2}{100gSample} = 13.5gBaCl_2[/tex]

We can calculate the number of moles in 13.5 g of barium chloride using its molar mass (208.23 g/mol).

[tex]13.5 g \times \frac{1mol}{208.23g} = 6.5 \times 10^{-2} mol[/tex]

A 427 g sample is 3.17% by mass barium chloride contains 6.5 × 10⁻² moles of BaCl₂.

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the answer is atomic numbers

Answer:

atomic numbers

Explanation:

In order for two atoms to be different, they have to have a different number of protons. Protons are represented by the atomic number. Thus, atoms of two DIFFERENT elements must have different atomic numbers.

I took the test and got 100%

Hope this helps!

Answer:

C. A tablet contains different chemical compounds

Explanation:

The dietary supplement in this question depicts a kind of matter. Matter, in chemistry, can either be a pure substance or a mixture. Unlike elements and compounds (pure substances) which cannot be separated by physical means, mixtures can be separated using physical method.

A mixture is a combination of different substances with varying physical properties, which serves as basis of their physical separation. According to the image in the question, the Calcium citrate dietary supplement contains different chemical compounds like polyethylene glycol, sodium, methyl cellulose, magnesium silicate etc.

These chemical compounds retain their individual properties and can be separated easily via physical techniques, hence, the dietary supplement is a MIXTURE.

Answer:

See explanation

Explanation:

What I have written in the image attached is called a nuclear equation. It differs from a chemical reaction equation in the sense that it involves transformations that occur in the nucleus of atoms.

The nuclear equation must be balanced. This means that the mass and charge on both sides of the reaction equation must be the same.

On the left hand side the U-235 interacts with a neutron. The total mass on the left hand side is 236 while the total charge is 92. If we sum up the masses and charges of Ba and Kr, we also get a total of 236 mass units and a charge of 92.

Hence the other nucleus is barium-141

Answer:

The air inside and outside are equal so air particles can go in and out. The can is empty so the air particles go in and out. That is why the can wont get crushed.

Explanation:

Air pressure  does not crush an empty soft-drink can that is sitting on a table in your house as the pressure is equal outside and inside of the can.

Pressure is defined as the force applied on an object perpendicular to it's surface per unit area over which it is distributed.Gauge pressure is a pressure which is related with the ambient pressure.

There are various units by which pressure is expressed most of which are derived units which are obtained from unit of force divided by unit of area . The SI unit of pressure is pascal .

It is a scalar quantity which is related to the vector area element with a normal force acting on it.It is distributed over solid boundaries and across arbitary sections of fluid normal to the boundaries at every point.

Learn more about pressure,here:

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#SPJ2

Answer:  D) 11

Explanation:

We have 1 iron atom (the Fe)

We have 5 carbon (denoted [tex]C_5[/tex])

We have 5 oxygen atoms (denoted [tex]O_5[/tex])

So we have 1+5+5 = 11 atoms in this compound.

In one formula unit of  [tex]\rm FeC_5O_5[/tex], the number of atoms of oxygen has been 5. Thus , option B is correct.

Formula unit has been the empirical representation of the chemical compound. The formula has been responsible to deliver the information about the number of atoms of each elements present in the sample.

The given compound has been [tex]\rm FeC_5O_5[/tex]. The formula has subscript with each element representing the number of atoms.  The atoms of each element has been:

The number of atoms of oxygen present in one formula unit of [tex]\rm FeC_5O_5[/tex] has been 5. Thus , option B is correct.

For more information about the formula unit, refer to the link:

https://brainly.com/question/19293051

Answer:

c,a,b,d

Explanation:

a = 7.5 m/s²

Hi there !

Newton's second law

F = m×a => a = F/m

1 N = 1kg·m/s²

a = (75kg.m/s²)/10kg

= 7.5 m/s²

Good luck !

Answer:

The answer is B(scale)

Explanation:

Since the question asked about a range, the scale would be the most logical answer since scales are used to measure.

Answer:

the answer is C.

Explanation:

Answer:

0.0181 mol H

Explanation:

Step 1: Given data

Moles of water (H₂O) formed during the analysis: 0.00905 mol H₂O

Step 2: Calculate the amount (mol) H in 0.00905 mol H₂O

According to the chemical formula of water, the molar ratio of water to hydrogen is 1:2, that is, there are 2 moles of H per 1 mole of H₂O. We will use this conversion factor to calculate the moles of H in 0.00905 moles of H₂O.

0.00905 mol H₂O × (2 mol H/1 mol H₂O) = 0.0181 mol H

Answer:

A

Explanation:

Using the equation above, the dipole moment is calculated to be 1.85 D by multiplying the distance between the oxygen and hydrogen atoms by the charge difference between them and then finding the components of each that point in the direction of the net dipole moment (the angle of the molecule is 104.5˚).

Answer:

True

Explanation:

Because atoms with the same number of valence electrons react in similar ways with other elements.