Compound A (C9H12) shows prominent peaks in its mass spectrum at m/z 120 and 91. Compound B (also C9H12) shows prominent peaks at m/z 120 and 105. On vigorous oxidation with chromic acid, both compounds give benzoic acid. From this information, deduce the structures of both compounds.

Answer:

These are the chemical names and molecular formula of the compounds formed from these elements:

Answer:

58.702

Explanation:

Data obtained from the question include:

Mass number of isotope 1 (M1) = 57.93

Abundance of isotope 1 (M1%) = 67.76%

Mass number of isotope 2 (M2) = 59.93

Abundance of isotope 2 (M2%) = 26.16%

Mass number of isotope 3 (M3) = 60.93

Abundance of isotope 3 (M3%) = 1.25%

Mass number of isotope 4 (M4) = 61.93

Abundance of isotope 4 (M4%) = 3.66%

Mass number of isotope 5 (M5) = 63.93

Abundance of isotope 5 (M5%) = 1.16%

Relative atomic mass =...?

The relative atomic mass(RAM) of the element can be obtained by doing the following:

RAM = [(M1×M1%) /100] +[(M2×M2%) /100] + [(M3×M3%) /100] + [(M4×M4%) /100] + [(M5×M5%) /100]

RAM = [(57.93×67.76)/100] + [(59.93×26.16)/100] + [(60.93×1.25) /100] + [(61.93×3.66)/100] + [(63.93×1.16)/100]

RAM = 39.253 + 15.678 + 0.762 + 2.267 + 0.742

RAM = 58.702

Therefore, the relative atomic mass (RAM) of the element is 58.702

Answer:

At lower temperatures the solubility of the KCl decreased and recrystallization occurred

Explanation:

Solubility refers to the amount of solute that dissolves in one litre of water at a particular temperature. Solubility is a property referring to the ability for a given substance, the solute, to dissolve in a solvent. It is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium. The resulting solution is called a saturated solution.

Solubility is dependent on temperature. This is the reason why we must state the particular temperature at which a given solubility data was collected. Above or below the quoted temperature, the solubility data may no longer be accurate.

Let's return to the question, at elevated temperatures, we can see that the KCl is very soluble in water as evidenced by the clear solution obtained at high temperature. However, as the temperature decreases, the solubility of KCl also decreases accordingly and recrystallization of the solute occurred hence the formation of a cloudy solution and the settling of some solid at the bottom of the flask.

Answer:

C. At lower temperatures the solubility of the KCl decreased and recrystallization occurred

Explanation:

Answer:

II. The orbitals have different shapes.  

IV. The orbitals have different energies.  

Explanation:

1. Shapes

Below are pictures of a 3s and a 3p orbital.

The 3s orbital has a spherical shape, and the 3p orbital has a dumbbell shape.

2. Energies

For every element except H, the order of energies is

3s < 3p

For a hydrogen atom,

3s = 3p

Answer:

A constant volume calorimeter (bomb calorimeter) was calibrated by performing in it a reaction in which 5.23 kJ of heat energy was released, causing the calorimeter to rise by 7.33 °C. What is the heat capacity Cy of the calorimeter

Explanation:

the heat capacity of the calorimeter is

[tex]C_v = \frac{q}{\Delta T} \\\\=\frac{5.23}{7.33} \\\\=0.714kJ /^\circ C[/tex]

Now that our  heat capacity of the calorimeter is 0.714kJ/°C

we can easily calculate  the change in internal energy ΔU of the neutralization reaction

[tex]\Delta U = C_v \ dt[/tex]

or

[tex]\Delta U = C_V \Delta T[/tex]

Δ T = 2.46 °C

[tex]C_v = 0.714 kJ/ ^\circ C[/tex]

[tex]\Delta U = 0.714*2.46\\\\=1.7564kJ[/tex]

Answer:

  7.86 g/cm³

Explanation:

  11.0 kg = 11,000 g

The density in g/cm³ is ...

  (11,000 g)/(1,400 cm³) = 7.86 g/cm³

Answer:

The wavelength is [tex]\lambda =97.3 nm[/tex]

Explanation:

Generally the series whose emission  line show on the visible spectrum is the

Balmar series so this two emission line seen on the visible spectrum  could either be due to the move of electron from

[tex]n=3 \to \ n=2[/tex]

OR

[tex]n=4 \to n=2[/tex]

This implies that the first excitement is from [tex]n_i=1 \to \ n_f=4[/tex]

So the energy change due to the excitement is mathematically represented as

     [tex]\Delta E = R_H [\frac{1}{n_i^2} -\frac{1}{n_f^2} ][/tex]

substituting values

       [tex]\Delta E= R_H [\frac{1}{1^2} -\frac{1}{4^2} ][/tex]

       [tex]\Delta E= \frac{15}{16} R_H[/tex]

This energy change can also be represented as

       [tex]\Delta E = \frac{hc}{\lambda}[/tex]      

So   [tex]\frac{15}{16} R_H = \frac{hc}{\lambda}[/tex]

=>    [tex]\lambda = \frac{16hc}{15 R_H}[/tex]

Where  [tex]R_H[/tex] is the Rydberg constant with a value of  [tex]R_H = 2.18 * 10^{-18} J.[/tex]

              h is the Planck's constant with values   [tex]h = 6.626 * 10^{-34} m^2 kg / s[/tex]

                c is the speed of light with value  [tex]c = 3.0*10^{8} \ m/s[/tex]

So

       [tex]\lambda = \frac{16(6.626 *10^{-34})(3*10^{8})}{15 * (2.18*10^{-18})}[/tex]

        [tex]\lambda = 9.73 *10^{-8} \ m[/tex]

       [tex]\lambda =97.3 nm[/tex]

Answer:

1. 2.3

2. 4.5

3. 10.5

4. 5.6

5. 3.5

6. 3.9

7. 1.6

Explanation:

pH = - log [H+]

1. Lemon juice

[H+] = 0.005

pH = - log [H+]

pH = - log 0.005

pH = 2.3

2. Beer

[H+] = 3.16x10^-5

pH = - log [H+]

pH = - log 3.16x10^-5

pH = 4.5

3. Milk of Magnesia

[H+] = 3.16x10^-11

pH = - log [H+]

pH = - log 3.16x10^-11

pH = 10.5

4. Rain water

[H+] = 2.51x10^-6

pH = - log [H+]

pH = - log 2.51x10^-6

pH = 5.6

5. Soda

[H+] = 3.16x10^-4

pH = - log [H+]

pH = - log 3.16x10^-4

pH = 3.5

6. Tomatoes

[H+] = 1.23x10^-4M

pH = - log [H+]

pH = - log 1.23x10^-4

pH = 3.9

7. Bleach

[OH-] = 2.3x10^-2M

pOH = - log [OH-]

pOH = - log 2.3x10^-2

pOH = 1.6

Answer:

Lactate dehydrogenase (LDH)

Explanation:

LDH is tetrameric enzyme found in the muscles (M-type) and the heart (H-type) of living cells, responsible for the conversion of pyruvate to lactate and back, to promote generation of nicotinamide adenine dinucleotide (NAD).

Answer:

The correct answer will be " RbF > RbCl > RbBr > Rbl".

Explanation:

The size of the given ions will be:

RbCl:

⇒  689kJ/mol

RbBr:

⇒  660kJ/mol

Rbl:

⇒  630kJ/mol

RbF:

⇒  785kJ/mol

Now according to the size, the arrangement will be:

⇒  (785kJ/mol) > (689kJ/mol) > (660kJ/mol) >(630kJ/mol)

⇒  RbF > RbCl > RbBr > Rbl

The bond among all opposite charging ions seems to be strongest whenever the ions were indeed small.

Answer:

The wavelength of the monochromatic light is 486.2 nm.

Explanation:

The illumination of the hydrogen atom by the monochromatic light causes an absorption of energy by its electrons which causes an excitation. After a period, the particle de-excites (decays) losing the absorbed energy and falls back to its initial state releasing the energy in the form of a photon. This photon can be observed as a colored light of the Balmer series.

From Rydberg's expression,

     1/λ=−R([tex]\frac{1}{n_{2} ^{2} }[/tex] − [tex]\frac{1}{n_{1} ^{2} }[/tex])

The transition of the electron is from n = 2 to 4, so that;

1/λ = R ([tex]\frac{1}{2^{2} }[/tex] - [tex]\frac{1}{4^{2} }[/tex])

    = 1.097 x [tex]10^{7}[/tex] ([tex]\frac{1}{2^{2} }[/tex] - [tex]\frac{1}{4^{2} }[/tex])

1/λ  = 2056875

So that,

λ = [tex]\frac{1}{2056875}[/tex]

  = 4.8617 x [tex]10^{-7}[/tex] m

The wavelength of the monochromatic light is 486.2 nm.

Answer:

Gravitational Energy: The energy of an object due to its movement

Mechanical Energy: The potential energy of position

Nuclear Energy: internal energy caused by vibrations of atoms and molecules

Thermal Energy: Energy stored in the nucleus of an atom

Answer:

radiant

nuclear

thermal

potential

Explanation:

Answer:

K=CHANGE IN CONCENTRATION/TIME TAKEN

Explanation:

Answer:

See explanation below

Explanation:

In this case, we can explain this in a very basic way.

We know that heavier objects will go always at the bottom when we are carrying two objects, one heavier than the other right?

In the same manner works the density of two liquids. In this case, we have a mix of water and bromoethane. Bromoethane is an organic compound and it's less polar than water which is extremely polar. When we mix these two liquids, we can see that both of them are insoluble, so no matter how much we shake the funnel, the liquids will not mix to form a solution.

Instead of that, both of them will be in the funnel, and they'll be gradually separating into two layers. The bromoethane has a higher density than water, this means that in the bottom layer we will have the bromoethane and in the top layer we will have the water.

In case you are wondering what happens if we added water first and then, the bromoethane?, it will happen the same, it does not matter the order you add the liquid, because density here is a very important factor, so when the water is added no matter which position, it will go to the top layer after the bromoethane is added.

Now when the hexane is added, it will form now three layers, and again, density plays an important factor. The higher density will go to the bottom, and the lowest to the top.

In this case, the order of layer will be:

Top layer: hexane (d = 0.66 g/mL)

Middle layer: water (d = 1 g/mL)

Bottom layer: bromoethane (d = 1.46 g/mL)

Hope this helps

Answer:

(3R,4R)-4-bromohexan-3-ol

Explanation:

In this case, we have  reaction called halohydrin formation. This is a markovnikov reaction with anti configuration. Therefore the halogen in this case "Br" and the "OH" must have different configurations. Additionally, in this molecule both carbons have the same substitution, so the "OH" can go in any carbon.

Finally, in the product we will have chiral carbons, so we have to find the absolute configuration for each carbon. On carbon 3 we will have an "R" configuration on carbon 4 we will have also an "R" configuration. (See figure 1)

I hope it helps!

Answer:

340.000 ppm

Explanation:

Parts per million (ppm) is a unit of measure for concentration that measures the number of units of substance per million units of the set. It is a concept homologous to the percentage, only in this case it is not parts per percent but per million. The ppm calculation method is different for solids, liquids and gase. There are many formulas, however in this case, you can use this fact:

[tex]10000ppm=1\%[/tex]

Using Cross-multiplication:

[tex]\frac{10000ppm}{x} =\frac{1\%}{34\%}[/tex]

Solving for [tex]x[/tex] :

[tex]x=34*10000=340000ppm[/tex]

Therefore, the concentration of a 34% solution converted to parts per million is:

[tex]340000ppm[/tex]

Answer:

K = 1.79x10⁻³³

Explanation:

Using Hess's law, it is possible to fin K of a reaction by the algebraic sum of another related reactions.

In the reactions:

1. N2(g)+O2(g) ⇌ 2NO(g), K1 = 4.10×10−31 2.

2. N2(g)+2H2(g) ⇌ N2H4(g), K2 = 7.40×10−26

3. 2H2O(g)⇌2H2(g)+O2(g), K3 = 1.06×10−10

The sum of 1/2 (1) + 1/2 (2) produce:

N2(g) + 1/2O2(g) + H2(g) ⇌ 1/2N2H4(g) + NO(g)

And K' = √4.1x10⁻³¹×√7.4x10⁻²⁶ = 1.74x10⁻²⁸

Now, this reaction + 1/2 (3):

N2(g) + H2O(g) ⇌ NO(g) + 1/2N2H4(g)

And K of reaction is:

1.74x10⁻²⁸×√1.06x10⁻¹⁰ = 1.79x10⁻³³

Answer:

[tex]3.06mol~C_6H_14[/tex]

Explanation:

We have to start with the reaction:

[tex]2C_6H_1_4 + 19O_2->12CO_2 + 14H_2O[/tex]

We have 2 carbons, 6 hydrogens and 38 oxygens on both sides.

Now the molar ratio between [tex]C_6H_14[/tex] and [tex]CO_2[/tex] is 2:12 or [tex]2~mol~C_6H_14=~12~mol~CO_2[/tex]. With this  in mind we can calculate the moles of [tex]C_6H_14[/tex], so:

[tex]18.4~mol~CO_2\frac{2~mol~C_6H_14}{12~mol~CO_2}=3.06mol~C_6H_14[/tex]

I hope it helps!

Answer:

B)    3.07 mol

Explanation:

Answer: Use the titration formula

Explanation:

Answer:

answer = -0.95

Explanation:

Answer:

Explanation:

The rate of reaction will not depend upon concentration of reactant . It will be always constant and equal to .0089M s⁻¹.

Initial moles of reactant = 400 x 10⁻³ mole in 5 L

molarity = 400 x 10⁻³ /5 M

= 80 x 10⁻³ M .

= .08M

no of moles reacted in 2 s  = .0089 x 2

= .0178 M

concentration left = .08 - .0178 M

= .0622 M .

No of moles left in 5 L

= 5 x .0622 = .31 moles .

Answer:

LDL is

low density lipid

HDL is

high density lipid

Explanation:

HDL helps rid your body is excess cholesterol so so it won't end up in your arteries

LDL is also called "bad cholesterol" because it takes cholesterol to your arteries

Answer:

The level is  [tex]n_1 = 5[/tex]

Explanation:

From the question we are told that

  The level of the hydrogen atom is   [tex]n_2 = 8[/tex]

  The wavelength of the photon is  [tex]\lambda = 3745 nm = 3745 *10^{-9} \ m[/tex]

Generally the wave number is mathematically represented as

        [tex]k = \frac{1}{\lambda }[/tex]

Now this wave number can also be mathematically represented as

       [tex]k = R_{\infty} [\frac{1}{n_1^2} + \frac{1}{n_2^2} ][/tex]  

This implies that

 So  

   Here [tex]R_{\infty}[/tex] is the Rydberg constant, with a value  [tex]1.097 * 10^7[/tex]

and  [tex]n_1 \ and \ n_2[/tex]  are the principal quantum levels

 substituting values

               [tex]0.0243= [\frac{1}{n_1^2} - \frac{1}{8^2} ][/tex]  

               [tex]0.0243= \frac{1}{n_1^2} - 0.015625[/tex]  

              [tex]0.0243 + 0.015625= \frac{1}{n_1^2}[/tex]

              [tex]n_1 = 5[/tex]  

Answer:  The correct answer is:  " endothermic . "

______________________________________

Note:  Heat flows into  [heat may be absorbed within] an "endothermic" reaction or system

          To the contrary, heat flows out  [heat   may exit from or may be released from] an "exothermic" reaction or process.

Hint:  Think of the "prefixes" of:  "endothermic"  and "exothermic" :

_____________________________________

  1)  endo- = "within" (as in "endothermic" —heat tends to be absorbed/"within"/"released within"/released within"/into" ;

  2) exo-   = " outwards"/"exit" (as in "exothermic") —heat tends to '"exit"/leave/escape from/"be released out of/form".

_____________________________________

Hope this is helpful to you!

Best wishes to you in your academic pursuits

     —and within the "Brainly" community"!

_____________________________________

Answer:

See answer below

Explanation:

In this case, you are missing the picture. Luckily I found one on another site, so I hope is the one you are asking for. If not, please post again with the picture.

According to the picture below, you need to write a chemical formula for each molecular model.

To do this, is just simple. Let's see each model per separate.

In the first model, we have a blue ball and three white balls. According to the nomenclature of the question a blue ball represents nitrogen atoms and white ball represents hydrogen, therefore, we have an atom of nitrogen bonded to three atoms of hydrogens, so, the chemical formula should be:

NH₃: This molecule corresponds to the Ammonia molecule.

The second picture, shows 4 black balls (representing an atom of carbon each) and each black ball holds a determinated number of white balls. The two of the middle have two white balls each, and the terminals have 3 white balls, therefore, the molecule should be the following:

CH₃ - CH₂ - CH₂ - CH₃: this corresponds to the butane

Finally, the last picture shows a yellow ball (which represents sulphur) and three red balls (representing oxygen each), so, the molecule that represents this would be:

SO₃: this is the sulfite ion.

Answer:

Option A. is correct

Explanation:

A reaction is at equilibrium when the amounts of the reactants and products are no longer changing.

Chemical equilibrium means that the rate of formation of products is equal to the rate at which the products re-form reactants.

Products are formed by the forward reaction and by the reverse reaction, the products re-form reactants.

Answer:

Sodium Chloride, Potassium Chloride

Explanation:

Sodium Chloride, Potassium Chloride, are the most common example of a strong electrolyte. Most salts are strong electrolytes, such as hydrochloric acid, nitric acid, perchloric acid and sulphuric acid. Strong bases, such as sodium hydroxide and calcium hydroxide, are also potent electrolytes.

hope this helped!

Answer:

The correct answer is 0.15 × 10⁻³ M.

Explanation:

C₆H₈O₇ is the molecular formula of citric acid. The mass of the one mole of the substance that comprise Avogadro's no of molecules is termed as the molar mass of the substance.  

The molar mass of the citric acid (C₆H₈O₇) will be,  

6 × atomic mass of carbon + 8 × atomic mass of hydrogen + 7 × atomic mass of oxygen = 6×12 + 8×1 + 7×16 = 192. Thus, the molar mass of citric acid is 192 g/mol.  

The value of the solution given in the question is 8 L.  

The mass of citric acid given is 0.24 g or 240 mg, which can also be written as 240/1000 g or 240 × 10⁻³ g.  

The number of moles can be calculated by using the formula = mass / molar mass. Thus, by putting the values we get,  

= 240 × 10⁻³ g / 192 g/mol

= 1.25 × 10⁻³ mol

The number of moles of the solute present in the 1 liter of the solution is termed as the molarity of the solution. The formula of molarity or M is,  

= no of moles of solute / volume of solution in L

Now putting the values we get,  

= 1.25 × 10⁻³ mol / 8 L

= 0.156 × 10⁻³ M

Hence, the molarity of citric acid in the given solution is 0.15 × 10⁻³ M

Answer:

A. CH2.

B. CH.

Explanation:

A. Determination of the empirical formula of polyethylene.

Data obtained from the question include:

Carbon (C) = 86%

Hydrogen (H) = 14%

The empirical formula of the polyethylene can be obtained as follow:

C = 86%

H = 14%

Divide by their molar mass

C = 86/12 = 7.17

H = 14/1 = 14

Divide by the smallest

C = 7.17/7.17 = 1

H = 14/7.17 = 2

Therefore, the empirical formula of the polyethylene is CH2.

B. Determination of the empirical formula of polystyrene

Data obtained from the question include:

Carbon (C) = 92.3%

Hydrogen (H) = 7.7%

The empirical formula of the polystyrene can be obtained as follow:

C = 92.3%

H = 7.7%

Divide by their molar mass

C = 92.3/12 = 7.69

H = 7.7/1 = 7.7

Divide by the smallest

C = 7.69/7.69 = 1

H = 7.7/7.69 =

Therefore, the empirical formula of the polystyrene is CH.

Answer:

1.05 V

Explanation:

Now recall Nernst equation;

Ecell= E°cell - 0.0592/n log [Red]/[Ox]

Now we look at the values of E°cathode and E°anode

E°cathode= 0.34 V

E°anode = -0.74 V

E°cell= 0.34-(-0.74)

E°cell= 1.08 V

[Red] = 1.453 M

[Ox] = 0.00176 M

n= 6

Ecell= E°cell - 0.0592/n log [Red]/[Ox]

Ecell= 1.08 - 0.0592/6 × log[1.453]/[0.00176]

Ecell= 1.08 - 0.0592/6 × 2.917

Ecell= 1.08 - 0.02878

Ecell= 1.05 V