Why can we use a water-ethanol mixture but not a water-hexane mixture as a recrystallization solvent? because water and hexane are ___________________.

Answer:

The rate at which heat is added in the boiler is 8128.610 kilowatts.

Explanation:

A boiler is a device that works at steady state, whose function is pressurizing and heating water. All gravitational electric and magnetic effects can be neglected. From First Law of Thermodynamics the boiler is characterized by the following model:

[tex]\dot Q_{in} + \dot H_{in}-\dot H_{out} + \dot K_{in} - \dot K_{out}= 0[/tex] (Eq. 1)

Where:

[tex]\dot Q_{in}[/tex] - Heat transfer rate, measured in kilowatts.

[tex]\dot H_{in}[/tex], [tex]\dot H_{out}[/tex] - Inlet and outlet fluid enthalpy rates, measured in kilowatts.

[tex]\dot K_{in}[/tex], [tex]\dot K_{out}[/tex] - Inlet and outlet kinetic energy rate, measured in kilowatts.

And by the Principle of Mass Conservation we have that:

[tex]\dot m_{in}-\dot m_{out} = 0[/tex] (Eq. 2)

Where [tex]\dot m_{in}[/tex] and [tex]\dot m_{out}[/tex] are mass flows at entrance and exit of the boiler, measured in kilograms per second.

Then, we clear the heat transfer rate and expand (Eq. 1) by definitions of enthalpy and kinetic energy, as well as (Eq. 2):

[tex]\dot Q_{in} = \dot H_{out}-\dot H_{in}+\dot K_{out}-\dot K_{in}[/tex]

[tex]\dot Q_{in} = \dot m \cdot \left[(h_{out}-h_{in}\right)+\frac{1}{2}\cdot (v_{out}^{2}-v_{in}^{2})\left][/tex] (Eq. 3)

Speeds of fluid entering and exiting the boiler ([tex]v[/tex]), measured in meters per second, are found by applying the following formula:

[tex]\dot m = \left(\frac{\pi}{4} \right)\cdot \frac{D^{2}\cdot v}{\nu}[/tex]

[tex]v = \frac{4\cdot \dot m\cdot \nu}{\pi\cdot D^{2}}[/tex] (Eq. 4)

Where:

[tex]\nu[/tex] - Specific volume of fluid, measured in cubic meters per kilogram.

[tex]D[/tex] - Inner diameter of pipe, measured in meters.

Entrance ([tex]\dot m = 2.778\,\frac{kg}{s}[/tex], [tex]\nu_{in} = 0.001093\,\frac{m^{3}}{kg}[/tex] and [tex]D_{in} = 0.08\,m[/tex])

[tex]v_{in} = \frac{4\cdot \left(2.778\,\frac{kg}{m^{3}} \right)\cdot \left(0.001093\,\frac{m^{3}}{kg} \right)}{\pi\cdot (0.08\,m)^{2}}[/tex]

[tex]v_{in}\approx 0.604\,\frac{m}{s}[/tex]

Specific enthalpy at given conditions is:

[tex]h_{in} = 640.09\,\frac{kJ}{kg}[/tex] (From Saturated Water tables)

Exit ([tex]\dot m = 2.778\,\frac{kg}{s}[/tex], [tex]\nu_{out} = 0.61731\,\frac{m^{3}}{kg}[/tex] and [tex]D_{out} = 0.30\,m[/tex])

[tex]v_{out} = \frac{4\cdot \left(2.778\,\frac{kg}{m^{3}} \right)\cdot \left(0.61731\,\frac{m^{3}}{kg} \right)}{\pi\cdot (0.30\,m)^{2}}[/tex]

[tex]v_{out} \approx 24.261\,\frac{m}{s}[/tex]

Specific enthalpy at given conditions is:

[tex]h_{out} = 3272.4\,\frac{kJ}{kg}[/tex] (From Superheated Steam tables)

If we know that [tex]\dot m = 2.778\,\frac{kg}{s}[/tex], [tex]h_{in} = 640.09\,\frac{kJ}{kg}[/tex], [tex]h_{out} = 3272.4\,\frac{kJ}{kg}[/tex], [tex]v_{in}\approx 0.604\,\frac{m}{s}[/tex], [tex]v_{out} \approx 24.261\,\frac{m}{s}[/tex], the heat transfer rate is:

[tex]\dot Q = \left(2.778\,\frac{kg}{s} \right)\cdot \left\{ \left(3272.4\,\frac{kJ}{kg}-640.09\,\frac{kJ}{kg} \right)+\frac{1}{2}\cdot \left[\left(24.261\,\frac{m}{s} \right)^{2}-\left(0.604\,\frac{m}{s} \right)^{2}\right] \right\}[/tex]

[tex]\dot Q = 8128.610\,kW[/tex]

The rate at which heat is added in the boiler is 8128.610 kilowatts.

Answer:

(A) A ball sitting on the ground

Explanation:

The option with the least gravitational potential energy in the question is : A: A ball sitting on the ground.

[tex]U= mgh[/tex]

h= height of the object

m= mass of the object.

Therefore, option A is right.

Learn more at:

https://brainly.com/question/3884855?referrer=searchResults

Answer:

0.0132 g CuSO₄

General Formulas and Concepts:

[tex]\text{Molarity}=\frac{\text{moles of solute}}{\text{liters of solution}}[/tex]

Explanation:

Step 1: Define variables

3.29 mL

4.00 M CuSO₄

x g CuSO₄

Step 2: Define conversions

1000 mL = 1 L

Step 3: Solve

Step 4: Simplify

We are given 3 sig figs.

0.01316 g CuSO₄ ≈ 0.0132 g CuSO₄

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:

D. Territory

Explanation:

Territory is defined as an area that is claimed by one or more individuals.

Territory is often used as a form of ownership of land or water mass between two parties. It is important as it gives each party a knowledge of their designated areas.

This validates it being an area that is claimed by one or more parties as organisms use that to protect their interest of food, water and mates for their survival.

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 molar mass of Na (sodium) is 23.0 g/moles

Explanation:

Answer:

the molar mass of Na (sodium) is 23.0 g/mol.

Explanation:

Answer:

The acceleration will be .5 and the force will be 37.5

Have a nice day!   :)

Answer:

Hello. The answer is 37.5N.

Explanation:

If you look carfully ، every time that you add one weight the force changes 2.5N so you can do this:

[tex](2.5 \times 5) + 25 = 37.5[/tex]

Answer:D. Both of their ions will have the same negative charge

Explanation:

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

Learn more about extraction here: https://brainly.com/question/15840419

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:

https://brainly.com/question/14760196

#SPJ2

Answer:

The answers of the questions are found below

Explanation:

1.) higher than

2.) solution and the liquid taste

3.) hard

4.) have varying solubilities

-Just took it on edge and got them all right

-Hope you do well <3 :)

The complete statement about ionic compounds is:

The melting point of an ionic compound is likely to be higher than a  molecular compound.

Ionic compounds are those compounds that are formed by holding ions with an electrostatic force, called ionic bonding. The compounds contain negatively charged ions called anions and positively charged ions called cations. The anions and cations connect together to form a  neutral compound.

The compounds are bound with an electrostatic force, so their melting point will be higher than the molecular compounds.

Thus, the melting point of an ionic compound is likely to be higher than a molecular compound.

To learn more about ionic compounds, refer to the link:

https://brainly.com/question/9167977

#SPJ5

Answer:

Silver.

Explanation:

Hello!

In this case, we can consider the specific heat as the property that we can analyze in order to answer to this question. In such a way, as the specific heat is known as the energy required to modify the temperature of 1 g of the substance by 1 °C, since the masses of all the substances are the same, we can that their specific heats are respectively 0.240, 0.444 and 4.184 J/(g°C), from the equation:

[tex]Q=mCp\Delta T[/tex]

We can see that the higher the specific heat (Cp) the lower the change in temperature considering their inversely proportional relationship. However, as 100 J of energy is applied to all the substances, we can see that silver will exhibit the largest temperature change because a higher change is needed to fit with the provided energy.

Best regards.

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:

a

Explanation:

It is critical to watch or observe what is happening with every step of your experiment

Answer:

a) What quantity (moles) of NaOH must be added to 1.0 L of 1.8 M HC2H3O2 to produce a solution buffered at pH = pKa?

Step 1: Data given

Volume of HC2H3O2 = 1.0 L

Molarity of HC2H3O2 = 1.8 M

Ka = 1.8*10^-5

ph = pK = -log(1.8*10^-5) = 4.74

Step 2:

Use the Henderson-Hasselbalch equation.

pH = pKa + log(A-/HA)

4.74 = 4.74 + log(A-/HA)

0 =  log(A-/HA)

A-/HA = 1

Consider X = moles of NaOH added (and moles of A- formed)

Remaining moles of HA = 1.8 - X

moles of A- = X

HA = 1.8 - X

X/(1.8-X) = 1

X =0.9

We have to add 0.9 mole NaOH to 1.0 L of 1.8 M HC2H3O2

To control we can do the following equation:

4.74 = 4.74 + log(0.9/0.9) = 4.74

b) What quantity (moles) of NaOH must be added to 1.0 L of 1.8 M HC2H3O2 to produce a solution buffered at pH = 4.00?

Step 1: Data given

Volume of HC2H3O2 = 1.0 L

Molarity of HC2H3O2 = 1.8 M

Ka = 1.8*10^-5

ph = 4

Step 2:

Use the Henderson-Hasselbalch equation.

pH = pKa + log(A-/HA)

4 = 4.74 + log(A-/HA)

-0.74 =  log(A-/HA)

A-/HA = 0.182

Consider X = moles of NaOH added (and moles of A- formed)

Remaining moles of HA = 1.8 - X

moles of A- = X

HA = 1.8 - X

X/(1.8-X) = 0.182

X =0.277

We have to add 0.277 mole NaOH to 1.0 L of 1.8 M HC2H3O2

To control we can do the following equation:

4 = 4.74 + log(0.277/1.523)

c) What quantity (moles) of NaOH must be added to 1.0 L of 1.8 M HC2H3O2 to produce a solution buffered at pH = 5.00

Step 1: Data given

Volume of HC2H3O2 = 1.0 L

Molarity of HC2H3O2 = 1.8 M

Ka = 1.8*10^-5

ph = 5

Step 2:

Use the Henderson-Hasselbalch equation.

pH = pKa + log(A-/HA)

5 = 4.74 + log(A-/HA)

0.26 =  log(A-/HA)

A-/HA = 1.82

Consider X = moles of NaOH added (and moles of A- formed)

Remaining moles of HA = 1.8 - X

moles of A- = X

HA = 1.8 - X

X/(1.8-X) = 1.82

X =1.16

We have to add 1.16 mole NaOH to 1.0 L of 1.8 M HC2H3O2

To control we can do the following equation:

5 = 4.74 + log(1.16/0.64) = 5

Explanation:

Answer:

Matter changes to a plasma state

Explanation:

Plasma is superheated matter, so when matter is heated to the point that electrons are stripped off of atoms forming ionized gas.  Palsma comprises over 99% of the observable universe.  Plasma is visible in the form of stars, nebulas, and sometimes even auroras.

Answer:

C. Matter changes to a plasma state.

Explanation:

Correct on Edge 2022!!!

Good luck everyone, you got this! Have a great day!

Answer:

its a physical change

Explanation:

its b

Answer:

a. Phosphoric Acid

b. Acetic Acid

c. Hypochlorous Acid

Explanation:

A buffer works when the pH of this one is in pKa ± 1. That means, to find which buffer system works in some pH you need to find pKa:

pKa = -log Ka

pKa Acetic acid:

-log1.8x10⁻⁵ = 4.74

pKa phosphoric acid:

-log7.5x10⁻³ = 2.12

pKa hypochlorous acid:

-log3.5x10⁻⁸ = 7.46

a. For a pH of 2.8 the best choice is phophoric acid because its effective range is: 1.12 - 3.12 and 2.8 is between these values.

b. pH 4.5. Acetic acid. effective between pH's 3.74 - 5.74

c. pH 7.5. Hypochlorous acid that works between 6.46 and 8.46

Answer:

a) 0.0379 M

b) 24.89 mL

c)  0.09 mL

Explanation:

The equation of the reaction is:

2HBr(aq) + Ca(OH)2(aq) ---> CaBr2(aq) + 2H20(l)

a)

Concentration of acid CA = 0.117 M

Concentration of base CB= ??

Volume of acid VA = 16.0 ml

Volume of base VB = 24.7 ml

number of moles of acid NA = 2

number of moles of base NB= 1

From;

CA VA/CB VB = NA/NB

CAVANB =CBVBNA

CB = CAVANB/VBNA

CB = 0.117 *16 * 1/ 24.7 *2

CB  = 1.872/49.4

CB = 0.0379 M

b)

CA = 0.270 M

CB = 0.113 M

VA = ??

VB =22.8mL

NA =2

NB =1

From;

CA VA/CB VB = NA/NB

CAVANB =CBVBNA

VA = CBVBNA/CANB

VA = 0.113 * 22.8 * 2/0.207 *1

VA = 24.89 mL

c)

using the dilution formula

C1V1 =C2V2

Where:

C1= initial concentration =10.8 M

V1 = initial volume = ??

C2= final concentration =0.400 M

V2= final volume = 2.5 L

V1 = C2V2/C1

V1 = 0.400 * 2.5/10.8

V1 = 0.09 mL

Answer:

c,a,b,d

Explanation:

Answer:extrinisic properties

i really need a brainliest

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:

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

Moles of Sr²⁺ = 0.3375

Molarity is a way to express the concentration of the solution

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

[tex]\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}[/tex]

Where

M = Molarity

n = Number of moles of solute

V = Volume of solution

So to find the number of moles can be expressed as

[tex]\boxed{\bold{n=V\times M}}[/tex]

Strontium phosphide (Sr₃P₂)

Sr₃P₂ ⇒ 3Sr ²⁺ + 2P³⁻

[tex]\tt 0.45~M \times 0.25~L=0.1125[/tex]

mol ratio Sr₃P₂ : Sr ²⁺ = 1 : 3

[tex]\tt \dfrac{3}{1}\times 0.1125=0.3375[/tex]

Answer:

True

Explanation:

According to some calculations, the Earth is losing 50,000 metric tons of mass every single year, even though an extra 40,000 metric tons of space dust converge onto the Earth's gravity well, it's still losing weight.

Answer:

true

Explanation:

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: it is covalent and there are 2 hydrogen molecules and 1 oxygen molecule.

Explanation: it just is