1. How many molecular orbitals can be built from the valence shell orbitals in O2?

Answer:

The correct option is d. ion exchange chromatography and gel filtration chromatography

Explanation:

The mixture contains proteins with different isoelectric points and molecular weights. Ion exchange chromatography separates the proteins with different electric charges, which depend on the isoelectric point. At certain pH of the aqueous medium, the proteins will have a certain electric charge and they will be retained differently in the stationary phase. Proteins A and D have similar isoelectric points (around 4.0) and maybe they cannot be efficiently separated by this method; the same occurs with protein B and C (with an isoelectric point around 9.0). To separate proteins A from D and protein B from C, it could be used gel filtration chromatography. This separation method is based on differences in molecular weights. So, at the end of the process, we will obtain the proteins A, B, C, D separated one from each other.

Answer:

% Free space in water = [tex]\frac{9.945* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.45%

% Free space in ice  = [tex]\frac{9.98* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.8%

Explanation:

As given ,

Density for ice at 0⁰C = 0.917 g/ml

Density for water at 0⁰C = 0.999 g/ml

Radii of H atoms = 37 pm

Radii of O atoms = 66 pm

Now,

Consider 1 ml of water = 1 cm²

As , we know that mass of water in 1 cm² = 0.999 g

Moles of water = [tex]\frac{0.999}{18} = 0.056[/tex]

Volume of H₂O = 1.624×[tex]10^{-31}[/tex] m²

Now,

Volume occupied by water = 0.056×6.022×[tex]10^{23}[/tex]× 1.624×[tex]10^{-31}[/tex] m²

                                              = 5.48×[tex]10^{-9}[/tex] m²

⇒Volume occupied by water = 5.48×[tex]10^{-9}[/tex] m²

Now,

Free space = 1×[tex]10^{-6}[/tex]  - 5.48×[tex]10^{-9}[/tex] = 9.95×[tex]10^{-7}[/tex] m²

% Free space = [tex]\frac{9.945* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.45%

Now,

Consider 1 ml of ice  = 1 cm²

S.I unit of ice = 1×[tex]10^{-6}[/tex] m²

As , we know that mass of water in 1×[tex]10^{-6}[/tex] m² = 0.917 g

Moles of ice = [tex]\frac{0.917}{18} = 0.012[/tex]

Volume of H₂O = 6.022×[tex]10^{23}[/tex] ×0.012

Volume of ice unit = [tex]\frac{4}{3} \pi (37*10^{-12})^{3} *2 + \frac{4}{3} \pi (66*10^{-12})^{3} = 1.624*10^{-31}m^{3}[/tex]

Now,

Volume occupied by water = 0.012×6.022×[tex]10^{23}[/tex]× 1.624×[tex]10^{-31}[/tex] m²

                                              = 1.17×[tex]10^{-9}[/tex] m²

⇒Volume occupied by water = 1.17×[tex]10^{-9}[/tex] m²

Now,

Free space = 1×[tex]10^{-6}[/tex]  - 1.17×[tex]10^{-9}[/tex] = 9.98×[tex]10^{-7}[/tex] m²

% Free space = [tex]\frac{9.98* 10^{-7} }{1*10^{-6} }[/tex]×100 = 99.8%

Answer:

A. percentage mass of iron = 5.17%

percentage mass of sand  = 8.62%

percentage mass of water = 86.205%

B. (Iron + sand + water) -------> ( iron + sand) ------> sand

C. The step of separation of iron and sand

Explanation:

A. Percentage mass of the mixtures:

Total mass of mixture = (15.0 + 25.0 + 250.0) g =290.0 g

percentage mass of iron = 15/290 * 100% = 5.17%

percentage mass of sand = 25/290 * 100% = 8.62%

percentage mass of water = 250/290 * 100% = 86.205%

B. Flow chart of separation procedure

(Iron + sand + water) -------> separation by filtration using filter paper and funnel to remove water --------> ( iron + sand) -----------> separation using magnet to remove iron ------> sand

C. The step of separation of iron and sand by magnetization of iron will have the highest amount of error because during the process, some iron particles may not readily be attracted to the magnet as they may have become interlaced in-between sand grains. Also, some sand particle may also be attracted to the magnet as they are are borne on iron particles.

Answer:

The answer is "A"

Explanation:

Please find the complete question in the attachment file.

[tex]\to R(s)= \frac{As}{K+s}[/tex]

when the s in the approach, that is infinity R(s) tends

[tex]\to \frac{A}{\frac{K}{s}+1} \\\\ \to\frac{A}{0+1} \\\\ \to\frac{A}{1} \\\\ \to A[/tex]

Answer:

the crust is the outermost layer

Explanation:

the mantle is under the crust, the core is the innermost layer

land and water.is for crust-mantle. contain semi-molten iron and nickel please make the question clear

Answer:

answer in picture

Explanation:

Explanation:

Conduction is a form of heat transfer between one body and another. It usually occurs when a warmer object is in contact with a cooler one. Heat generally flows from a region of high temperature to a place at a lower temperature.

Answer: a)  [tex]Fe[/tex] is the limiting reagent

b) 3.59 g

c) 11.6g

Explanation:

[tex]4Al_2O_3+9Fe\rightarrow 3Fe_3O_4+8Al[/tex]  

To calculate the moles :

[tex]\text{Moles of} Al_2O_3=\frac{27.5g}{102g/mol}=0.27moles[/tex]

[tex]\text{Moles of} Fe=\frac{8.4g}{56g/mol}=0.15moles[/tex]

According to stoichiometry :

a) 9 moles of [tex]Fe[/tex]  require= 4 moles of [tex]Al_2O_3[/tex]

Thus 0.15 moles of [tex]Fe[/tex] will require=[tex]\frac{4}{9}\times 0.15=0.067moles[/tex]  of [tex]Al[/tex]

Thus [tex]Fe[/tex] is the limiting reagent as it limits the formation of product and [tex]Al[/tex] is the excess reagent.

b) As 9 moles of [tex]Fe[/tex] give = 8 moles of [tex]Al[/tex]

Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{8}{9}\times 0.15=0.133moles[/tex]  of [tex]Al[/tex]

Mass of [tex]Al=moles\times {\text {Molar mass}}=0.133moles\times 27g/mol=3.59g[/tex]

c) As 9 moles of [tex]Fe[/tex] give = 3 moles of [tex]Fe_3O_4[/tex]

Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{3}{9}\times 0.15=0.05moles[/tex]  of [tex]Fe_3O_4[/tex]

Mass of [tex]Fe_3O_4=moles\times {\text {Molar mass}}=0..05moles\times 231.5g/mol=11.6g[/tex]

Answer:

66800 J

Explanation:

From the question given above, the following data were obtained:

Mass (m) = 200 g

Heat (Q) required =?

The heat required to melt the 200 g sample of water can be obtained as:

Mass (m) = 200 g

Latent heat of water (L) = 334 J/g

Heat (Q) required =?

Q = mL

Q = 200 × 334

Q = 66800 J

Thus, 66800 J of heat energy is required to melt the sample of water.

Answer:

66800 J

Explanation:

Answer: 0.25 mol × (6.02214 × 1023 /mol) = 1.5 × 10

Explanation: Hope that helps

Answer:

2KF+MgSO4

Explanation:

The correct product of the reaction above is 2KF + MgSO4.

A chemical reaction is a reaction in which the reactants or reacting substances react or combine together to produce the products.

Therefore, The correct product of the reaction above is 2KF + MgSO4.

Learn more about chemical reactions below.

https://brainly.com/question/11231920

#SPJ2

Answer:

B. The microscope paved the way

Explanation:

This section from the article, "History of the Cell: Discovering the Cell", that emphasizes the role of technological development in the discovery of cells, is the subheading, "The microscope paved the way". In this subheading, the author narrated how Robert Hooke improved the existing microscope, and was able to discover the cell through it.

Further improvement of the simple microscope by Antonie van Leeuwenhoek led to the discovery of bacteria and protozoa.

Answer:

1.93 x 10²⁶ formula units

Explanation:

Given parameters:

Number of moles of LiCl  = 3.2 x 10² moles  = 320moles

Unknown:

Number of formula units in this compound  = ?

Solution:

The mole is used a reference to determine the number of substances matters contain.

 A mole contains the Avogadro's number of particles.

 So;

       1 mole of a substance contains 6.02 x 10²³ formula units;

320 moles of LiCl will contain 320 x  6.02 x 10²³  = 1.93 x 10²⁶ formula units

Answer:

it's an artificial non-saccharide sweetener 200 times sweeter than sucrose, and is commonly used as a sugar substitute in foods and beverages. it's a methyl ester of the aspartic acid/phenylalanine dipeptide with the trade names NutraSweet, Equal, and Canderel

Explanation:

Answer:

Aspartame is some type of very sweet substance that is used as an artificial sweetener, and chiefly in low-calorie products. It is a derivative of aspartic acid and phenylalanine.

Explanation:

Answer:

Explanation:

The missing incomplete resonance structure is attached in the image below. From there, we can see the addition of the nonbonding electrons and its' formal charge which makes the resonance structure a complete resonance structure. The others two resonance structure that can be derived from the complete structure is also shown in the image. Out of these three structures, the structure that contributes most to the hybrid is the structure with the negative charge on the oxygen.

Answer:

Lighting the stove and cooking the meat are both chemical changes.

Explanation:

Both fire and cooking are chemical changes.

Answer:

the second one

Explanation:

Answer: A 15 kg cart being pushed with a 200 N force.

Explanation:

The 15 kg cart is the lightest, so it has the least amount of friction on the ground.

The cart that will result in the greatest change in speed is the cart with a mass of 15 Kg

The correct answer to the question is Option (A) A 15 kg cart being pushed with a 200 N force

Acceleration is defined as the change in velocity of an object with time.

Acceleration is also related to force and mass according to the following equation:

Acceleration (a) = Force (F) / mass (m)

a = F / m

For Option A:

Mass (m) = 15 Kg

Force (F) = 200 N

a = F / m

a = 200 / 15

For Option B:

Mass (m) = 25 Kg

Force (F) = 200 N

a = F / m

a = 200 / 25

For Option C:

Mass (m) = 45 Kg

Force (F) = 200 N

Acceleration (a) =?

a = F / m

a = 200 / 45

For Option D:

Mass (m) = 35 Kg

Force (F) = 200 N

a = F / m

a = 200 / 35

From the illustrations made above, we can see that the cart with a mass of 15 Kg has the greatest acceleration (i.e change in speed)

Therefore, the correct answer to the question is Option (A) A 15 kg cart being pushed with a 200 N force

Learn more: https://brainly.com/question/25816322

Answer:yes anything can be addictive

Explanation:

Answer:

While caffeine produces a small rise in dopamine, it does not cause the large surge that unbalances the reward circuits in the brain and is necessary for an addiction. So even though the word “addiction” is often used casually, caffeine is not addictive (scientifically speaking).

Answer:

0.57 water

Explanation:

To solve this problem, we need to write the reaction expression first.

The reactants are oxygen gas and hydrogen gas.

They react to give a product of water

       2H₂    +    O₂   →   2 H₂O  

Given that;

Number of moles of hydrogen gas = 0.57moles

From the balanced reaction expression;

       2 moles of hydrogen gas produces 2 moles of water

   So;

    0.57mole of hydrogen gas will also produce 0.57 water

Answer:

Organisms need to take food to get energy and perform life processes. A living organism undergoes many life processes like nutrition, respiration, digestion, transportation, excretion, circulation of blood, and reproduction. To perform all these life processes the organism needs energy and nutrients.

Explanation:

nnastarannnn his idea

Answer:

See explanation

Explanation:

Let us look at the situation closely, the undissociated Hmo is red in colour while the mo^- is yellow in colour.

This means that an acidic solution will appear red while a basic solution will appear yellow in colour.

NaC2H3O2 is a basic salt. When it is introduced, the acetate ion pulls a proton from water forming  CH3COOH. CH3COOH is a weak acid and largely does not dissociate, it means that the undissociated acid remains in the solution leaving only the OH^- ions floating around thereby making the solution basic.

The colour of the system now changes to yellow.

Consider the equilibrium;

CH3COO^-(aq) + H2O(l) ------> CH3COOH(aq) + OH^-

Addition of NaC2H3O2  causes the equilibrium of this system to shift to the right.

The methyl orange water equilibrium also shifts towards the position where more mo^-(yellow) is produced.

Answer:

Q= Magnesium R= Chlorine

Explanation:

The element Q should be magnesium and R is chlorine.

An ionic compound is a compound that is formed by the combination of a metal and non-metal. Such bonds forms when there is a transfer of electrons from the metals to the non-metals. This leaves a net positive charge on the metal and a negative charge on the non-metal.

The electrostatic attraction leads to the formation of the bond.

 To solve this problem, the hypothetical compound is QR₂

       Mg                        Cl

     2 8 2                    2 8 7

So, Mg transfers 2 electrons to two atoms of chlorine.

 This leads to the formation of the compound MgCl₂

Answer:

the answer is d

hope this helpssss

Answer:

radial energy because it's a heat energy!

Explanation:

There are more types but that's the closest in my opinion!!

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Thermal Energy

Explanation:

known as heat energy produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.

Answer:

Air temperature increases.

Explanation:

The air temperature at Riverdale School increases if the groundwater system were used because this system uses very huge amount of water than the other system. By using more molecules having the same temperature, the thing with more molecules has more total kinetic energy or thermal energy than the thing with fewer molecules so that's why air temperature of the school is increases.

Answer:

a) final pressure inside the tank is 242.4 atm

b)

Work = 0

heat q = 1440.85 kJ

DU = 1440.85 kJ

Explanation:

Given that;

Pressure P1 = 172 atm

Volume V = 80 L

Temperature T1 = 20°C = ( 273.15 + 20) = 293.15 K

Temperature T2 = 140°C = ( 273.15 + 140) = 413.15 K

we know that, gas constant R = 0.0821 atm.L/mol.K

from the Ideal Gas equation;

pV = nRT1

n = pV/RT1

we substitute

n = (172 × 80) / (0.0821 × 293.15)

n = 13760 / 24.067615  

n = 571.72 moles

now

P2 = nRT2/V2

P2 = (571.72 × 0.0821 × 413.15) / 80

P2 = 19392.5222 / 80

P2 = 242.4 atm

Therefore, final pressure inside the tank is 242.4 atm

b)

we know

w = -∫[tex]P_{ext}[/tex] dv

now, since there is no change in volume; dv = 0

so

w = 0

Work = 0

dU = cVDT

Cv = nCr,m

Cv = 571.72 ×  21.0

Cv = 12007.12 J/k

DU = CvΔT

DU = 12007.12 × (413.15 - 293.15)

DU = 1440854.4 J

DU = 1440.85 kJ

DU = q + w

1440.85 = q + 0

heat q = 1440.85 kJ