Find ΔErxn for the combustion of biphenyl. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 5.86 kJ/∘C. Express the energy in kilojoules per mole to three significant figures. View Available Hint(s)

Answer:

C18H24O3

Explanation:

Step 1:

Data obtained from the question. This include the following:

Mass of estriol = 13.42g

Mass of CO2 = 36.86g

Mass of H2O = 10.06g

Molar mass of estriol = 288.38g/mol

Step 2:

Determination of the mass of Carbon (C), Hydrogen (H) and Oxygen (O) present in the compound. This is illustrated below:

For Carbon, C:

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Mass of C in CO2 = 12/44 x 36.86 = 10.05g

For Hydrogen, H:

Molar Mass of H2O = (2x1) + 16 = 18g/mol

Mass of H in H2O = 2/18 x 10.06 = 1.12g

For Oxygen, O:

Mass of O = 13.42 – (10.05 + 1.12) = 2.25g

Step 3:

Determination of the empirical formula for estriol. This is illustrated below:

C = 10.05g

H = 1.12g

O = 2.25g

Divide by their molar mass

C = 10.05/12 = 0.8375

H = 1.12/1 = 1.12

O = 2.25/16 = 0.1406

Divide by the smallest i.e 0.1406

C = 0.8375/0.1406 = 6

H = 1.12/0.1406 = 8

O = 0.1406/0.1406 = 1

Therefore, the empirical formula for estriol is C6H8O

Step 4:

Determination of the molecular formula for estriol. This is illustrated below:

Molecular formula is simply a multiple of the empirical formula i.e

Molecular formula => [C6H8O]n

[C6H8O]n = 288.38g/mol

[(12x6) + (8x1) + 16]n = 288.38

[72 + 8 + 16]n = 288.38

96n = 288.38

Divide both side by 96

n = 288.38/96 = 3

Molecular formula => [C6H8O]n

=> [C6H8O]n

=> [C6H8O]3

=> C18H24O3

Therefore, the molecular formula for estriol is C18H24O3

The compound is C18H24O3.

From the information in the question;

Mass of C = 36.86 g/44 g/mol × 12 g/mol = 10.1 g

Number of moles of carbon = 10.1 g/12 g/mol = 0.84 moles

Mass of hydrogen = 10.06 g/18 g/mol × 2 g/mol = 1.11 g

Number of moles of hydrogen = 1.11 g/1g/mol = 1.11 moles

Mass of oxygen = 13.42 - (10.1 g + 1.11 g) = 2.21 g

Number of moles of oxygen = 2.21g/16 g/mol = 0.14 moles

Dividing through by the lowest number of moles;

C - 0.84 moles/0.14 moles   H -  1.11 moles/0.14 moles   O - 0.14 moles/0.14 moles

C - 6   H - 8    O -1

The empirical formula is C6H8O

The molecular formula of the compound is;

[6(12) + 8(1) + 16]n = 288.38

n =  288.38/86 =3

The compound is C18H24O3

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Answer: 9.53 *2= 19.06

Explanation:

The law of multiple proportions states that if two elements combines to form more than one compound the ratio of masses of the second element which combines to the fixed mass of the first element will always be the ratios of the small whole numbers.

in case of carbon monoxide, mass of carbon will be the same of mass of oxygen.

But in case of carbon dioxide, if carbon is 9.53 units then oxygen will be twice as that of carbon.

CO2, so 9.53*2= 19.06 grams of oxygen will combine with 9.53 grams of carbon to form carbon dioxide.

Answer:

Biosphere

Explanation:

because of the rain it gets from huge water sources.

I hope that was useful.

Answer: The volume of the balloon at this altitude is 46.3 L

Explanation:

Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law

The combined gas equation is,

[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]

where,

[tex]P_1[/tex] = initial pressure of gas = 755 mm Hg

[tex]P_2[/tex] = final pressure of gas (at STP) = 385 mm Hg

[tex]V_1[/tex] = initial volume of gas = 27.6 L

[tex]V_2[/tex] = final volume of gas = ?

[tex]T_1[/tex] = initial temperature of gas = [tex]29.9^0C=(29.9+273)K=302.9K[/tex]

[tex]T_2[/tex] = final temperature of gas = [tex]-14.1^0C=((-14.1)+273)K=258.9K[/tex]

Putting all the values we get:

[tex]\frac{755\times 27.6}{302.9}=\frac{385\times V_2}{258.9}[/tex]

[tex]V_2=46.3L[/tex]

Thus the volume of the balloon at this altitude is 46.3 L

Answer: The change in internal energy of the gas is +408 J

Explanation:

According to first law of thermodynamics:

[tex]\Delta E=q+w[/tex]

[tex]\Delta E[/tex] =Change in internal energy

q = heat absorbed or released

w = work done or by the system

w = work done on the system= [tex]-P\Delta V[/tex]

As volume is constant , [tex]\Delta V[/tex] = 0 and w = 0.

q = +408J   {Heat absorbed by the system is positive}

[tex]\Delta E=+408J+(0J)=+408J[/tex]

Thus the change in internal energy of the gas is +408 J

Answer:

[tex]Rate=2.57x10^{-3}\frac{M}{s}[/tex]

Explanation:

Hello,

In this case, for the reaction:

[tex]2N_2O(g) \rightarrow 2N_2(g)+O_2(g)[/tex]

We can easily compute the average rate by firstly computing the final concentration of oxygen:

[tex][O_2]=\frac{0.017mol}{0.440L}=0.0386M[/tex]

Then, we compute it by using the given interval of time: from 0 seconds to 15.0 seconds and concentration: from 0 M to 0.0386M as oxygen is being formed:

[tex]Rate=\frac{0.0386M-0M}{15.0s-0s}\\ \\Rate=2.57x10^{-3}\frac{M}{s}[/tex]

Regards.

According to the question,

The reaction will be:

Now,

The final concentration of O₂ will be:

→ [tex][O_2] = \frac{0.017}{0.440}[/tex]

          [tex]= 0.0386 \ M[/tex]

hence,

The rate of reaction will be:

= [tex]\frac{0.0386-0}{15.0-0}[/tex]

= [tex]2.57\times 10^{-3} \ M/s[/tex]

Thus the above approach is right.

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Answer:

Even all compounds are neutral.

Explanation:

Some of them exhibit polarity. Because of the difference in electron affinity of the constituent atoms, the shared electrons are pulled towards the atom with high affinity to electrons.

Answer:

10.8 mm

Explanation:

Step 1: Calculate the volume (V) of the copper cylinder

The cylinder has a mass of 94.6754 g and a density of 8.96 g/cm³. The volume of the cylinder is:

[tex]94.6754 g \times \frac{1cm^{3} }{8.96g} = 10.6 cm^{3}[/tex]

Step 2: Calculate the length (h) of the copper cylinder

The diameter (d) of the copper cylinder is 3.52 cm. We can calculate the length using the following expression.

[tex]V = \pi \times (\frac{d}{2})^{2} \times h\\h = \frac{4V}{\pi \times d^{2} } = \frac{4(10.6cm^{3} )}{\pi \times (3.52cm)^{2} } = 1.08 cm[/tex]

Step 3: Convert the length to millimeters

We will use the relationship 1 cm = 10 mm.

[tex]1.08cm \times \frac{10mm}{1cm} = 10.8 mm[/tex]

The given question is incomplete, the complete question is:

CsCl crystallizes in a unit cell that contains the Cs+ ion at the center of a cube that has a Cl- at each corner. Each unit cell contains __________ Cs+ ions and __________ Cl-, ions, respectively.

a. 1 and 8

b. 2 and 2

c. 2 and 1

d. 2 and 4

e. 1 and 1

Answer:

The correct answer is option e, that is, 1 and 1.

Explanation:

A regular and a small geometric unit of a crystal that illustrates the repeating pattern of the crystal lattice is termed as a unit cell. Based on the given question, crystallization of CsCl takes place in a unit cell that comprises the ion of Cs+ at the center of a cube, which possesses Cl- at every corner.  

In the given case, in the center of the lattice one atom of Cs is present, therefore, there is one ion of Cs for one unit cell. It is known that there are 8 corners of a cube, and Cl- ion is situated at each corner. So,  

8 corners * (1 Cl ion/8 corners) = 1 Cl ion

Hence, the ratio of Cs+ : Cl- is 1:1.  

Each unit cell contains 1 [tex]Cs^{+}[/tex] ion(s) and 1 [tex]Cl^{-}[/tex] ion(s), respectively.

CsCl has a cubic structure that consists of an infinite chain of ions. The Cs (or Cl) ions sit at the eight corners of the cube and the Cl (or Cs) sit at the center of the cube.

It is given that:

The Cs ion([tex]Cs^{+}[/tex]) is present at the center of a cube and  [tex]Cl^{-}[/tex] is present at each corner.

It is known that there are total 8 corners  in a cube and [tex]Cl^{-}[/tex] is present at each corner.

So, 8 corners * (1  [tex]Cl^{-}[/tex]  ion/ 8 corners)=1  [tex]Cl^{-}[/tex]  ion

And also, Cs ion at present at the center of a cube thus 1 [tex]Cs^{+}[/tex] ion for one unit cell.

Thus the ration of [tex]Cs^{+}[/tex]: [tex]Cl^{-}[/tex] is 1:1 and each unit cell contains 1 [tex]Cs^{+}[/tex] ion(s) and 1 [tex]Cl^{-}[/tex] ion(s), respectively.

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Answer:

T = 136.5K

Explanation:

Explanation:

8H+(aq) + MnO4-(aq) + 5Fe2+(aq) → Mn2+(aq) + 5Fe3+(aq) + 4H2O(l)

To determine if a substance was reduced or oxidized, the oxidation number at the reactant and product side is compared.

When oxidation occurs, an element loses electrons and its oxidation number increases (becomes more positive). When reduction occurs, an element gains electrons and its oxidation number decreases or is reduced (becomes more negative).

H+ (oxidized or reduced) Answer 1 Choose...

There is an increase in oxidation number from 0 to 1. This means H+ was oxidized.

MnO4- (oxidizing or reducing agent) Answer 2 Choose...

In chemistry, an oxidizing agent is a substance that has the ability to oxidize other substances — in other words to accept their electrons

MnO4- is a strong oxidizing agent.

Fe2+ (oxidizing or reducing agent) Answer 3 Choose...

A reducing agent means it will itself get oxidized. In  this reaction, Fe2+ is the reducing agent.

Fe2+ (oxidized or reduced) Answer 4 Choose...

Oxidized

O in MnO4- (oxidized or reduced) Answer 5 Choose...

There is no change in oxidation number of , so it was neither reduced nor was it oxidized.

Mn in MnO4- (oxidized or reduced) Answer 6 Choose...

There is a decreaase in oxidation number from +7 to +2. This means reduction.

Answer:

At 415.2nm and 519.6nm, the dyes observed by the instrument are violet and green respectively.

Explanation:

In the electromagentic spectrum, visible wavelengths cover a range from approximately 400 to 800 nm. The colours of the spectrum range from red to violet (Red, Orange, Yellow, Green, Blue, Indigo and violet: a.k.a ROGBIV), in order of decreasing wavelength.

I hope this explanation would suffice.

Answer:

To limit pJ changes in solution

Answer:

101.63° C

Explanation:

Volume expansivity γa = γr -  γ g = 18 × 10⁻⁵ - 2.0 × 10⁻⁵ = 16 × 10⁻⁵ /K

v₂ - v₁ / v₁θ = 16 × 10⁻⁵ /K

(500 - 492 ) mL / (492 × 16 × 10⁻⁵) = θ

θ = 101.63° C

Answer:

the activation energy Ea = 179.176 kJ/mol

it will take  7.0245 mins for the same food to cook in an open pot of boiling water at an altitude of 10000 feet.

Explanation:

From the given information

[tex]T_1 = 100^0 C = 100+273 = 373 \ K \\ \\ T_2 = 113^0 C = 113 + 273 = 386 \ K[/tex]

[tex]R_1 = \dfrac{1}{7}[/tex]

[tex]R_2 = \dfrac{1}{49}[/tex]

Thus; [tex]\dfrac{R_2}{R_1} = 7[/tex]

Because at 113.0°C; the rate is 7 time higher than at 100°C

Hence:

[tex]In (7) = \dfrac{Ea}{8.314}( \dfrac{1}{373}- \dfrac{1}{386})[/tex]

1.9459 = [tex]\dfrac{Ea}{8.314}* 9.0292 *10^{-5}[/tex]

[tex]1.9459*8.314 = Ea * 9.0292*10^{-5}[/tex]

[tex]16.1782126= Ea * 9.0292*10^{-5}[/tex]

[tex]Ea = \dfrac{16.1782126}{ 9.0292*10^{-5}}[/tex]

Ea = 179.176 kJ/mol

Thus; the activation energy Ea = 179.176 kJ/mol

b)

here;

[tex]T_2 = 386 \ K \\ \\T_1 = (89.8 + 273)K = 362.8 \ K[/tex]

[tex]In(\dfrac{R_2}{R_1})= \dfrac{Ea}{R}(\dfrac{1}{T_1}- \dfrac{1}{T_2})[/tex]

[tex]In(\dfrac{R_2}{R_1})= \dfrac{179.176}{8.314}(\dfrac{1}{362.8}- \dfrac{1}{386})[/tex]

[tex]In (\dfrac{R_2}{R_1}) = 0.00357[/tex]

[tex]\dfrac{R_2}{R_1}= e^{0.00357}[/tex]

[tex]\dfrac{R_2}{R_1}= 1.0035[/tex]

where ;

[tex]R_2 = \dfrac{1}7{}[/tex]

[tex]R_1 = \dfrac{1}{t}[/tex]

Now;

[tex]\dfrac{t}{7}= 1.0035[/tex]

t = 7.0245 mins

Therefore; it will take  7.0245 mins for the same food to cook in an open pot of boiling water at an altitude of 10000 feet.

a). The activation energy given by the reactions related to the cooking of food in the pressure cooker would be:

[tex]Ea = 179.176 kJ/mol[/tex]

b). The time duration that is taken by the same food to cook in an open vessel would be:

[tex]7.0245 mins[/tex]

a). Given that,

Temperature [tex]1[/tex]  [tex]= 100[/tex]° C

Temperature [tex]2[/tex] [tex]= 113[/tex]° C

In Kelvin,

Temperature  [tex]1[/tex] [tex]= 100 + 273[/tex]

[tex]= 373 K[/tex]

Temperature  [tex]2[/tex] [tex]= 113 + 273[/tex]

[tex]= 386 K[/tex]

[tex]R_{1} = 1/7\\R_{2} = 1/49[/tex]

∵ [tex]R_{2}/R_{1} = 49/7 = 7[/tex]

It is given that at  [tex]113[/tex] rate [tex]=[/tex] [tex]7[/tex] × [tex]100[/tex]°C

Therefore,

[tex]Ea/8.314 (1/373 - 1/386) =[/tex] [tex]In(7)[/tex]

so,

[tex]Ea[/tex] [tex]= 16.1782126/(9.0292 * 10^{-5})[/tex]

∵ Activation energy [tex]= 179.176 kJ/mol[/tex]

b). As we know,

[tex]T_{2}[/tex] [tex]= 386 K[/tex]

[tex]T_{1}[/tex] [tex]= (89. 8 + 273)[/tex]

[tex]= 362.8 K[/tex]

by employing the formulae,

[tex]In(\frac{R_{2} }{R_{1} }) = \frac{Ea}{R} (1/T_{1} - 1/T_{2})[/tex]

[tex]In(\frac{R_{2} }{R_{1} }) = 179.176/8.314 (1/362.8 - 1/386)[/tex]

By solving this, we get

[tex]R_{2}/R_{1} = 1.0035[/tex]

Thus,

[tex]R_{2} = 1/7[/tex]

[tex]R_{1} = 1/t[/tex]

∵ t [tex]= 7.0245 min[/tex]

Thus, the time duration would be [tex]7.0245 minutes[/tex].

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Answer:

(a) [tex]BaCl_2(aq)+Na_2SO_4(aq)\rightarrow BaSO_4(s)+2NaCl(aq)[/tex]

(b) The particles of the formed barium sulfate remain suspended in the aqueous media forming a colloid.

Explanation:

Hello,

In this case, when solutions of barium chloride and sodium sulfate are mixed, the following chemical reaction is carried out:

[tex]BaCl_2(aq)+Na_2SO_4(aq)\rightarrow BaSO_4(s)+2NaCl(aq)[/tex]

Thus, we can notice that the product barium sulfate remains solid since its solubility in aqueous media is very low, for that reason at the beginning the solution becomes cloudy as its particles remain suspended in the water forming a colloid. Nevertheless, after some days, the suspended particles get precipitated by the effect of the gravity, therefore, we observe the solid on the bottom of the beaker.

Regards.

Answer:

B. s, p, d, f

Explanation:

These things are often referred to as suborbitals and you normally have s,p,d,f.

S has 1 two orbitals

P has 3 orbitals

D has 5 orbitals

F has 7 orbitals

and each orbital can house 2 electrons

Answer:

B. None of these

Explanation:

Sulfur has less ionization energy than phosphorus because sulfur has a pair of electron in its 3p subshell that increases electron repulsion in sulfur and sulfur electrons can easily remove from its sub-level.

While, there are no electron pairs in 3p subshell of phosphorus, therefore it requires more energy to remove an electron from 3p subshell.

Hence, the reason is electron repulsion and the correct answer is B.

Answer:

See explanation

Explanation:

In this case, we have 2 types of reactions. [tex]CH_3CH_2ONa[/tex] is a strong base but only has 2 carbons therefore we will have less steric hindrance in this base. So,  the base can remove hydrogens that are bonded on carbons 1 or 6, therefore, we will have a more substituted alkene (1-methylcyclohex-1-ene).

For the  [tex]KOC(CH_3)_3[/tex] we have more steric hindrance. So, we can remove only the hydrogens from carbon 7 and we will produce a less substituted alkene (methylenecyclohexane).

See figure 1

I hope it helps!

Answer:

The gas and liquid is in equilibrium.

Explanation:

liquids within a container undergoes state change, changing into gas. If this container is left open, these gases will escape into the external environment. In a situation in which the container is closed, the molecules that leave the liquid surface as gas will eventually condense on contact with the cover wall and change back into the liquid state. Some of these gases will reenter the liquid surface. At first, more of the liquid is transformed into gas and escape into the space above the liquid surface. Eventually, the available space becomes saturated with vapor, and then some of the gases start entering the liquid phase at the same rate as the liquid enters the gas phase. At this stage, the gas and liquid phase now exists in equilibrium.

Answer:

7

Explanation:

N-14 has 7

i looked it up ye ur probably gonna get it right

Answer:

7 protons + 7 neutrons!

Explanation:

Answer:

Br - has the largest radius

Explanation:

These ions each have achieved the nearest noble gas configuration. Br - has a like electron configuration to that of Krypton, S2- has a like electron configuration to that of Argon,  B3+ to Helium, Mg2+ to Neon, and Li+ to Helium.

_______________________________________________________

Traveling down a group, the radius tends to increase as atom gains another shell. Here we are comparing elements of like electron configuration to the noble gases Helium, Neon, Argon, Krypton. Krypton, being the last element present in the group out of the 4, has the greatest radius as it has the most shells. Thus, Br - has the largest radius.

Hope that helps!

Answer:

Velocity

Explanation:

it is the rate of displacement over time in a SPECIFIED DIRECTION i.e it has both magnitude and direction

Answer:

Polythene bags are so lightweight and aerodynamic, they are easily picked up and carried by the wind. They can escape from trash bins, recycle bins, garbage trucks, and landfills, and end up littering the landscape.

hope it helps

Explanation:

Answer:

The correct answer is - 27 grams.

Explanation:

salts contain atoms (ions) like Na+ and Cl, these atoms are electrically charged that leads to a big crystal as they can stick together. Those are too heavy to evaporate.

When you heat the hot plate water evaporates but the salt does not leave vessel so, the concentration of salt in the water increases. In the end, the concentration of salt gets so high and the salt will begin to recrystallize into a solid. When all of the water is gone, you will have salt left behind in the same concentration.

Thus, the correct answer is - 27 grams.

Answer:

The answer is option c.

I hope this helps you.

Answer:

A. A + B + C --> D

Explanation:

Step 1: A + B --> X (fast)

Step 2: X + C --> Y (slow)

Step 3: Y --> D (fast)

To obtain the overall reaction, we have to sum up the reactants and products of all step and eliminate the intermediates.

Reactants:

A + B + X + C + Y

Products:

X + Y + D

So we have;

A + B + X + C + Y  --> X + Y + D

Upon elimination of intermediates, we have;

A + B + C --> D

The correct option is A.

Answer:

The volume increases because the temperature increases and is 2.98L

Explanation:

Charles's law states that the volume of a gas is directely proportional to its temperature. That means if a gas is heated, its volume will increase and vice versa. The equation is:

V₁/T₁ = V₂/T₂

Where V is volume and T is absolute temperature of 1, initial state, and 2, final state of the gas.

In the problem, the gas is heated, from 53.00°C (53.00 + 273.15 = 326.15K) to 139.00°C (139.00 + 273.15 = 412.15K).

Replacing in the Charles's law equation:

2.36L / 326.15K= V₂/412.15K

Answer:

See below

Explanation:

* Burning fire wood is given to be our first option. Now burning tends to be a property of wood, and it does effect the chemical compositions of it. Wood, in the presence of fire / oxygen, turns into ash and carbon dioxide.

* Decomposition is recognized as a chemical change, and heating copper carbonate is a perfect example of decomposition. When energy is added to this chemical process, the copper carbonate decomposes into copper oxide.

* Mixing sodium chloride solution and silver nitrate solution. When this reaction takes place, a white precipitate of AgCl is formed. And of course, this is a chemical reaction.

* When acids or bases come in contact with citric acid, the pH degree changes much. Due to this, carbon dioxide bubbles are formed.

* When eggs are fried they absorb the heat in the pan. Doing so the egg starts to curl a bit, resulting in the formation of new particles.

_______________________________________________________

I hope this gave you a start!