Write a balanced half-reaction for the reduction of aqueous arsenic acid H3AsO4 to gaseous arsine AsH3 in basic aqueous solution. Be sure to add physical state symbols where appropriate.

Answers

Answer 1

Answer:

H₃AsO₄(aq) + 4 H₂O(l) + 8 e⁻ ⇒ AsH₃(g) + 8 OH⁻(aq)

Explanation:

Let's consider the half-reaction for the reduction of aqueous arsenic acid to gaseous arsine in a basic aqueous solution.

H₃AsO₄(aq) ⇒ AsH₃(g)

We see that there is an excess of 4 oxygen atoms on the left side. So, we add 4 molecules of water to the left side and 8 hydroxyl ions to the right side.

H₃AsO₄(aq) + 4 H₂O(l) ⇒ AsH₃(g) + 8 OH⁻(aq)

We need to add 8 electrons to the left side to balance the reaction electrically.

H₃AsO₄(aq) + 4 H₂O(l) + 8 e⁻ ⇒ AsH₃(g) + 8 OH⁻(aq)

Answer 2

Answer:

[tex]H_3AsO_4(aq)+8H^+(aq)+8e^-=AsH_3(g)+4H_2O(l)[/tex]

Explanation:


Related Questions

Which of the following functional groups is not present in the HIV protease inhibitor drug below called Saquinavir?
A) alcohol
B) amide
C) aromatic ring
D) amine
E) ketone N. ○ ト Saquinavir Structure

Answers

Answer:

alcohol

Explanation:

Since in its chemical structure it presents an amide, amine and aromatic ring group.

What this drug does is inhibit the protease of the HIV retrovirus, the protease is an enzyme that catalyzes proteins.

What mass of benzene is cooled from 83.8 °C to 77.1 °C when 167 J of energy is transferred out of the system? (The specific heat of benzene is 1.740 J/g °C).

Answers

Answer:

14.32g

Explanation:

Initial temperature = 83.8°C

Final temperature = 77.1°C

Temperature change, ΔT = 83.8°C - 77.1°C = 6.7

Heat, H = 167J

Specific heat, c = 1.740J/g °C

m = ?

All these parameters are related with the equation below;

H = mcΔT

m = H / cΔT

m = 167 /  (1.740 * 6.7)

m = 167 / 11.658 = 14.32g

8. Exactly 169.5 J will raise the temperature of 10.0 g of a metal from 25.0°C to 60.0°C. What is the specific heat capacity of the metal?

Answers

Answer:

THE SPECIFIC HEAT OF THE METAL IS 0.4843 J/G °C

Explanation:

Heat involved in the reaction is 169.5 J

mass of the metal = 10 g

Change in temperature = 60 °C - 25 °C = 35 °C

Specific heat of the metal = unknown

Specific heat of a metal or substance is the amount of heat per unit mass required to raise the temperature by one degree Celsius.

Using the formula for heat of a reaction, which is:

Heat = mass * specific heat * change in temperature

Heat = m C ΔT

Re-arranging the formula by making C the subject of the formula, we get:

C = Heat / m ΔT

C = 169.5 J / 10 g * 35 C

C = 169.5 J / 350 g °C

C = 0.4843 J/g°C

So therefore, the specific heat of the metal is 0.4843 J/ g°C

Calcium carbide, CaC2, reacts with water to form calcium hydroxide and the flammable gas ethyne (acetylene) in the reaction: What mass of ethyne can be produced

Answers

Answer:

1 mole of CaC₂ will produce 26g of C₂H₂ or 64.1g of CaC₂ will produce 26g of C₂H₂

Explanation:

Hello,

To solve this question, we'll require a balanced chemical equation of reaction between calcium carbide and water.

Equation of reaction

CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂

Molar mass of calcium carbide (CaC₂) = 64.1g/mol

Molar mass of water (H₂O) = 18g/mol

Molar mass of calcium hydroxide (Ca(OH)₂) = 74g/mol

Molar mass of ethyne (C₂H₂) = 26g/mol

From the equation of reaction, 1 mole of CaC₂ will produce 1 mole of C₂H₂

1 mole of CaC₂ = mass / molar mass

Mass = 1 × 64.1

Mass = 64.1g

1 mole of C₂H₂ = mass / molar mass

Mass = 1 × 26

Mass = 26g

Therefore, 1 mole of CaC₂ will produce 26g of C₂H₂

Note: this is a hypothetical calculation since we were not given the initial mass of CaC₂ that starts the reaction

Suppose that you add 28.8 g of an unknown molecular compound to 0.250 kg of benzene, which has a K f Kf of 5.12 oC/m. With the added solute, you find that there is a freezing point depression of 3.06 oC compared to pure benzene. What is the molar mass of the unknown compound

Answers

Answer:

THE MOLAR MASS OF THE UNKNOWN COMPOUND IS 242.02 g/mol.

Explanation:

First:

Calculate the change in freezing point:

          Freezing point of pure benzene = 5.5°C

Change in temperature = 5.5 - 3.06 = 2.44 °C

Second:

Using the formula:

Δt = i Kf m

Let's assume i = 1

Kf = 5.12 °C/m

M = x / 0.250 kg of benzene

Then we can calculate x which is the molarity

Re-arranging the formula, we have:

m = Δt / i Kf

x / 0.250 = 2.44 / 1 * 5.12

x = 2.44 * 0.250 / 5.12

x = 0.61 / 5.12

x = 0.119 M

Since it is well known that molarity is the mass of a substance divided by its molar mass. We can then calculate the molar mass.

Molar mass = Mass / molarity

Molar mass = 28.8 g / 0.119 M

Molar mass =242.02 g/mol

Hence, the molar mass of the unknown molecular compound is 242.02 g/mol.

Calculate the work (kJ) done during a reaction in which the internal volume expands from 28 L to 51 L against an outside pressure of 4.9 atm.

Answers

Answer:

W= -11KJ

Explanation:

Given:

volume expands from 28 L to 51 L

pressure =4.9 atm.

We will need to Convert the pressure to Pascal SI

But 1 atm = 101,325 Pa.

Then,

Pressure= (4.9*101323)/1atm = 5*10^5 pa

Then we need to Convert the volumes to cubic meters

But we know that1 m³ = 1,000 L.

V1= 28L * 1m^3/1000L = 0.028m^3

V2=51L × 1m^3 /1000L =0.051m^3

The work done during the expansion of a gas can be calculated as

W= -P(V2-V1)

W= - 5*10^5(0.051m^3 - 0.028m^3)

W= -1.1× 10^4J

Then we can Convert the work to kiloJoule

But1 kJ = 1,000 J.

W= -1.1× 10^4J× 1kj/1000J

= -11KJ

The Ka1 value for oxalic acid is 5.9 x10-2 , and the Ka2 value is 4.6 x 10-5 . What are the values of Kb1 and Kb2 of the oxalate ion

Answers

Answer:

2.17x10⁻¹⁰ = Kb1

1.69x10⁻¹³ = Kb2

Explanation:

Oxalic acid, C₂O₄H₂, has two intercambiable protons, its equilibriums are:

C₂O₄H₂ ⇄ C₂O₄H⁻ + H⁺ Ka1 = 5.9x10⁻²

C₂O₄H⁻ ⇄ C₂O₄²⁻ + H⁺ Ka2 = 4.6x10⁻⁵

Oxalate ion, C₂O₄²⁻, has as equilibriums:

C₂O₄²⁻ + H₂O ⇄ C₂O₄H⁻ + OH⁻ Kb1

C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2

Also, you can know: KaₓKb = Kw

Where Kw is 1x10⁻¹⁴

Thus:

Kw = Kb2ₓKa1

1x10⁻¹⁴ =Kb2ₓ4.6x10⁻⁵

2.17x10⁻¹⁰ = Kb1

And:

Kw = Kb1ₓKa2

1x10⁻¹⁴ =Kb1ₓ5.9x10⁻²

1.69x10⁻¹³ = Kb1

That is because the inverse reaction of, for example, Ka1:

C₂O₄H⁻ + H⁺ ⇄ C₂O₄H₂ K = 1 / Ka1

+ H₂O ⇄ H⁺ + OH⁻ K = Kw = 1x10⁻¹⁴

=

C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2 = Kw × 1/Ka1

pls answer these questions for brainliest

katya is investigating displacement reactions . She heats the pairs of substances in this list

iron and aluminium oxide
iron and copper oxide
copper and magnesium oxide
iron and lead oxide

a)write down the letters os 2 pairs of substances that react . Explain your choices

b) choose one pair of substances that react . write a word equation for the reaction​

Answers

a) iron and copper oxide
iron and lead

because in electrochemical series, iron is located higher ( more electronegative ) than opper and lead

b) Fe + AlO = FeO + Al

2. A student has a centrifuge tube containing 14.0 g of t-butanol and is asked to make a 1.2 m solution of ethanol/t-butanol. How much ethanol would the student need to add in mL and in g? Show your calculations. Show your calculations. (6 pts)

Answers

Answer:

0.774g of ethanol

0.970mL of ethanol

Explanation:

Molality is an unit of concentration defined as the ratio between moles of solute and kg of solvent.

In the problem, you need to prepare a 1.2m solution of ethanol (Solute) in t-butanol (solvent).

14.0g of butanol are 0.014kg and as you want to prepare the 1.2m solution, you need to add:

0.014kg × (1.2moles / kg) = 0.0168 moles of solute = Moles of ethanol

To convert moles of ethanol to mass you require molar mass (Molar mass ethanol, C₂H₅OH = 46.07g/mol). Thus, mass of 0.0168 moles are:

0.0168moles Ethanol ₓ (46.07g / mol) =

0.774g of ethanol

And to convert mass in g to mL you require density of the substance (Density of ethanol = 0.798g/mL):

0.774g ₓ (1mL / 0.798g) =

0.970mL of ehtanol

The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 178C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.

Answers

A) The specific humidity of the air with the given parameters is;

w1 = 0.00967

B) The relative humidity of the air with the given parameters is;

Φ1 = 0.459

C) The enthalpy of the air in KJ/kg dry air with the given parameters is;

h1 = 49.75 KJ/Kg

Correct question is;

The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 17 °C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.

We are given;

Atmospheric Pressure;P = 95 KPa

Dry temperature;T1 = 25 °C

Wet temperature;T2 = 17°C

A) From table A-4 attached and at temperature of 17°C and by interpolation, we have a saturation pressure of P_g2 = 1.938 kpa

First of all, we will calculate the specific humidity from the given pressure and saturation pressure with the formula;

w2 = (0.622 × P_g2)/(P - P_g2)

w2 = (0.622 × 1.938)/(95 - 1.938)

w2 = 0.013

Now, let's calculate specific humidity with the enthalpies at 17 °C and by interpolation. We have specific enthalpies from table A-4 as;

h_fg2 = 2460 KJ/Kg

h_g1 = 2546.5 KJ/Kg

h_f2 = 71.36 KJ/Kg

The formula for the specific humidity under these conditions is;

w1 = (c_p(T2 - T1) + w2•h_fg2)/(h_g1 - h_f2)

c_p of air has a value of 1.005 KJ/Kg.°C

Thus;

w1 = (1.005(17 - 25) + 0.013*2460)/(2546.5 - 71.36)

w1 = 0.00967

B) The relative humidity is determined from the equation;

Φ1 = (w1*p)/(0.622 + w1)p_g1

From table A-4 attached and at temperature of 25 °C, we have a saturation pressure of P_g1 = 3.1698 KPa

Φ1 = (0.00967*95)/(0.622 + 0.00967)3.1698

Φ1 = 0.459

C) For the enthalpy of air, h1 we will use the formula;

h1 = (c_p × T1) + (w1 × h_g1)

h1 = (1.005 × 25) + (0.00967 × 2546.5)

h1 = 49.75 KJ/Kg

Read more at; https://brainly.com/question/13826648

Which of the following pairings usually forms molecular compounds?
Select the correct answer below:
metal, nonmetal
nonmetal, nonmetal
metal, metal
none of the above

Answers

A nonmetal and a nonmetal will make molecular compounds like H2O and CO2

the reation between sulfur dioxide and oxygen is a dynamic equilibrium. what happens when the pressure of the system is
increased ?

Answers

Answer:

In the above reaction, sulfur dioxide and oxygen react together to form sulfur trioxide. This means that an increase in pressure would move the equilibrium to the right and result in more sulfur trioxide being formed. Pressure can only affect the position of equilibrium if there is a change in the total gas volume.



A client with a long history of cigarette smoking and poorly controlled hypertension is

experiencing psychomotor deficits due to hemorrhagic brain damage. Which diagnosis is likely

for the onset of progressive dementia?

Answers

Answer:

It may be a hemorrhagic stroke because of the patient's history.

Explanation:

Uncontrolled hypertension could generate a hemorrhagic stroke within the brain generating the sign of progressive dementia, this is due to the vessel breaking due to the excess pressure of the internal light, it breaks and releases or extravases all the bloody contents to the brain

The difficulty of this is that the brain is the one that yields to a force in relation to the skull, that is why it is compressible against hemorrhage generating these signs as progressive dementia and could even be death or vegetative state

What volume of a 2.25 M sodium chloride solution will contain 4.58 moles of sodium chloride
(NaCl)?
A. 0.252 L
B. 119 L
C. 5.62 L
D. 0.491 L
E. 2.04 L

Answers

Answer:

Option E. 2.04 L

Explanation:

Data obtained from the question include:

Molarity of NaCl = 2.25 M

Mole of NaCl = 4.58 moles

Volume =..?

Molarity is simply defined as the mole of solute per unit litre of the solution. It is represented mathematically as:

Molarity = mole /Volume

With the above formula, we can obtain the volume of the solution as follow:

Molarity = mole /Volume

2.25 = 4.58/volume

Cross multiply

2.25 x volume = 4.58

Divide both side by 2.25

Volume = 4.58/2.25

Volume = 2.04 L

Therefore, the volume of the solution is 2.04 L

which vitamin is more soluble in water ? explain

Answers

Answer:

Vitamin C and B complex is the water soluble.but in question option is A abd C so, among them vitamin C is the water soluble vitamin.

Explanation:

Because it is easily soluble in water and when there is more amount of asorbic acid it has to be mixed in urine and are released out from body.

hope it helps..

Grams of cl in 38g of cf3cl

Answers

Answer:

114 grams

Explanation:

3chlorines per compound*38grams=114

How many water molecules are in a block of ice containing 0.500 mol of water (H2O)?

Answers

Answer:

3.01 × 10²³ molecules

Explanation:

Step 1: Given data

Moles of water (n): 0.500 mol

Step 2: Calculate the molecules of water present in 0.500 moles of water

In order to perform this calculation, we will use the Avogadro's number: in 1 mole of water there are 6.02 × 10²³ molecules of water.

0.500 mol × (6.02 × 10²³ molecules/1 mol) = 3.01 × 10²³ molecules

How many moles of CO are produced when 1.2 moles C reacts? Equation: 5C(s)+2SO2(g)→CS2(l)+4CO(g)

Answers

Answer:

0.96 mol CO

Explanation:

We simply just use the reaction to help us find this:

[tex]1.2 mol C(\frac{4 mol CO}{5 mol C} )[/tex]

Multiply it out and we get 0.96 as our answer.

Which one of the following substances, when dissolved in water at equal molar concentrations, will give the solution with the lowest electrical conductivity

a. CaC12
b. HNO3
c. NH3
d. C6H12O6 (glucose)
e. CO2

Answers

Answer:
Explanation: e. CO2

The substance which gives more ions in ionization will be more conductive and those giving less ions will be less conducting. Here, glucose only give no ion in water thus, it has the lower conductivity.

What is ionization?

Ionization is the process of dissociation of compounds into its constituent ions. For example, HCl when dissolved in water will give H+ and Cl- ions. Similarly HNO₃  gives H+ and NO₃- ions in ionization.

Water can easily dissolves the ionic compounds by forming hydrogen bonds with them and thus easily ionises them The ions formed are mobile and conduct electricity. The more the number of ions the higher the electrical conductivity.

CaCl₂ gives Ca²⁺ and two Cl- ions and NH₃ gives NH₄⁺ ions and CO₂ gives H+ ions by the formation of carbonic acid. Wheres, glucose does not give its ions and thus has lower conductivity for the solution.

To find more on conductivity, refer here:

https://brainly.com/question/15085692

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How many hours does it take to form 15.0 L of O₂ measured at 750 torr and 30°C from water by passing 3.55 A of current through an electrolytic cell?

Answers

Answer:

The correct answer is 17.845 hours.

Explanation:

To solve the question, that is, to determine the hours required there is a need to combine the Faraday's law of electrolysis with the Ideal gas law.  

Based on Faraday's law, m = Mit/nF

Here m is the mass in grams, M is the molecular mass, i is the current in amperes, t is time, n is the number of moles of electron per mole of oxygen formed and F is the Faraday's constant (the value of F is 96487 coulombs/mole).  

From the above mentioned equation,  

t = mnF/Mi ------(i)

Now based on ideal gas law's, PV = nRT or PV = m/M RT, here n = mass/molecular mass.  

So, from the above gas law's equation, m = PVM/RT

Now putting the values of m in the equation (i) we get,  

t = PVMnF/MiRT = PVnF/iRT

Based on the given information, the value of P is 750 torr or 750/760 atm = 0.98 atm, the value of v is 15.0 L, T is 30 degree C or 273 + 30 K = 303 K, i is 3.55 Amperes, and the value of R is 0.0821 atm L/mol K.  

1 mole of oxygen gives 2 moles of electrons, therefore, 2 moles of oxygen will give 4 moles of electrons.  

Now putting the values we get,  

t = PVnF/iRT

= 0.98 atm × 15.0 L × 4 moles of electron × 96487 coulombs per mole / 3.55 coulomb per sec × 0.0821 atm L per mole-K × 303 K

= 64243.81 secs or 64243.81/3600 hr  

= 17.845 hours

Which of the possible compounds has a mass of 163 grams when
6.13 x 1024 molecules of the compound is put on a scale?

Answers

Answer:

CH4

Explanation:

In solving this problem, we must remember that one mole of a compound contains Avogadro's number of elementary entities. These elementary entities include atoms, molecules, ions etc. Recall that one mole of a substance is the amount of substance that contains the same number of elementary entities as 12g of carbon-12. The Avogadro's number is 6.02 × 10^23.

Hence we can now say;

If 163 g of the compound contains 6.13 ×10^24 molecules

x g will contain 6.02 × 10^23 molecules

x= 163 × 6.02 × 10^23 / 6.13 × 10^24

x= 981.26 × 10^23/ 6.13 ×10^24

x= 160.1 × 10^-1 g

x= 16.01 g

x= 16 g(approximately)

16 g is the molecular mass of methane hence x must be methane (CH4)

help please !!!!!!!!

Answers

Answer:

Option B. 2096.1 K

Explanation:

Data obtained from the question include the following:

Enthalpy (H) = +1287 kJmol¯¹ = +1287000 Jmol¯¹

Entropy (S) = +614 JK¯¹mol¯¹

Temperature (T) =.?

Entropy is related to enthalphy and temperature by the following equation:

Change in entropy (ΔS) = change in enthalphy (ΔH) / Temperature (T)

ΔS = ΔH / T

With the above formula, we can obtain the temperature at which the reaction will be feasible as follow:

ΔS = ΔH / T

614 = 1287000/ T

Cross multiply

614 x T = 1287000

Divide both side by 614

T = 1287000/614

T = 2096.1 K

Therefore, the temperature at which the reaction will be feasible is 2096.1 K

Which one of the following would have the largest dispersion forces?
A) CH3CH2SH
B) CH3NH2
C) CH4
D) CH3CH3

Answers

Answer:

A) CH3CH2SH

Explanation:

Dispersion forces are weak attractions found between non-polar and polar molecules. The attractions here can be attributed to the fact that a  non-polar molecule sometimes become polar because the constant motion of its electrons may lead to an uneven charge distribution at an instant. If this happens, the molecule has a temporary dipole. This dipole can induce the neighbouring molecules to be distorted and form dipoles as well. The attractions between these dipoles constitute the Dispersion Forces.

Therefore; the greater the molar mass of a compound or molecule, the higher the Dispersion Force. This implies that the compound or molecule with the highest molar mass have the largest dispersion forces.

Now; for option (A)

CH3CH2SH

The molar mass is :

= (12 + (1 × 3 ) +12 + (1 ×2) + 32+1)

= (12 + 3+ 12 + 2 + 32 + 1)

= 62 g/mol

For option (B)

CH3NH2

The molar mass is:

= (12 + (1 ×  3 ) +14 + (1 ×  2)

= (12 + 3 + 14 + 2)

= 31 g/mol

For option (C)

CH4

The molar mass is :

= 12 + (1 × 4)

= 12 + 4

= 16 g/mol

For option (D)

CH3CH3

The molar mass is :

= 12 + ( 1 × 3 ) + 12 + ( 1 × 3)

= 12 + 3 + 12 + 3

= 30 g/mol

Thus ; option (A) has the highest molar mass, as such the largest dispersion force is A) CH3CH2SH

What is the new mass/volume percent (m/v) of a KOH solution that is prepared by diluting 110 mL of a 6.0% (m/v) KOH solution to 330 mL

Answers

Answer:

The new mass/volume percent is 2.0% (m/v)

Explanation:

Dilution is a procedure by which the concentration of a solution is decreased, generally with the addition of a diluent. In other words, dilution is a process in which a concentrated solution is always started, to which a greater volume of solvent is added, causing the concentration and volume of the resulting solution to change. But the amount of solute used to prepare the initial solution remains the same.

The calculation of a dilution is made by:

Cinitial. Vinitial = Cfinal. Vfinal

where C indicates concentration and V indicates volume.

In this case:

Cinitial: 6.0% (m/v)Vinitial: 110 mLCfinal: ?Vfinal: 330 mL

Replacing:

6.0% (m/v) * 110 mL= Cfinal* 330 mL

Solving:

[tex]Cfinal=\frac{ 6.0 (m/v)*110 mL}{330 mL}[/tex]

Cfinal=   2.0% (m/v)

The new mass/volume percent is 2.0% (m/v)

Strontium crystallizes in a face-centered cubic unit cell having an edge length of 77.43 pm. What is the atomic radius of strontium (in picometers) based on this structure

Answers

Answer:

Atomic radius of Strontium is 27.38pm

Explanation:

In a face-centered cubic structure, the edge, a, could be obtained using pythagoras theorem knowing the hypotenuse of the unit cell, b, is equal to 4r:

a² + a² = b² = (4r)²

2a² = 16r²

a = √8 r

As edge length of Strontium is 77.43pm:

77.43pm / √8 = r

27.38pm = r

Atomic radius of Strontium is 27.38pm

In Sir Isaac Newton's time in the early 1700s, what was the general consensus among scientists on the properties of light?

Answers

Answer:

Light is composed of particles and travels in a straight line.

Explanation:

The general consensus among scientists in Sir Isaac Newton's time in the early 1700s was that light was composed of a steady stream of particles, since it was observed that light traveled in a straight line and was able to pass through a vacuum. They argued along the lines of Sir Isaac Newton that since sound travels in waves and cannot travel though a vacuum, light must consist of something other than waves, such as particles.

Also, on reflection of light from rough surfaces, the particle theory suggests that if the surface is very rough, the particles bounce away at different angles from the surface, scattering the light as is confirmed by experimental observation.

In his 1704 book Opticks, Sir Isaac Newton stated that "Light is never known to follow crooked passages nor to bend into the shadow". This idea lent support to the particle theory, which proposes that light particles must always travel in straight lines. If the particles encounter the edge of a barrier, then they will cast a shadow because the particles not blocked by the barrier continue on in a straight line and cannot spread out behind the edge. This was observed in eclipses as well as formation of shadow of objects.

Answer:

 

Light is composed of particles and travels in a straight line.

Explanation:

PF The majority of scientists in the early 1700s agreed that light must be particle-like, since it was apparent that light traveled in a straight line and was able to pass through a vacuum. Their logic was that since sound travels in waves and can't travel though a vacuum, light must consist of something other than waves, such as particles.

A piece of silver with a mass 368 g has a heat capacity of 87.2 J/°C. What is the specific heat of
silver?
A. 0.385 J/g.°C
B. 0.237 J/g.°C
C. 0.184 J/g.°C
D. 1.322 J/g.°C
E. 4.184 J/g.°C

Answers

Answer:

B

Explanation:

Heat capacity = mass x specific heat capacity.

(C = mc)

87.2 = 368 x c

= 0.237 J/g.°C

What is the systematic name for the given compound? (R)-2-bromobutane (S)-2-bromobutane (R)-2-butyl bromide (S)-2-butyl bromide

Answers

Answer:

See explanation below

Explanation:

IUPAC came up with the idea of an unambiguous system of nomenclature for organic compounds. This unambiguous system relates the structure of a compound with its name. Thus, IUPAC has established a worldwide standard for the unambiguous naming of organic compounds. Scientists all over the world can now have a uniform system of nomenclature for compounds in order to facilitate easy communication of scientific information.

The systematic names of the following compounds listed in the question are shown below;

(R)-2- butyl bromide has the systematic name (R)-2-bromobutane

(S)-2-butyl bromide has the systematic name (S)-2-bromobutane

This unified system of nomenclature avoids the confusion created by the use of different trivial names in deferent localities and by various scientific academies. This is a major advantage of the systematic nomenclature.

If 0.98 g of an unknown was dissolved in 10.30 g of solvent and the resulting solution has a molality of 0.45 m, what is the molar mass of the unknown

Answers

Answer:

211.4g/mol.

Explanation:

Data obtained from the question includes:

Mass of unknown compound = 0.98g

Mass of solvent = 10.30g

Molality = 0.45 M

Next, we shall determine the number of mole of the unknown compound present in the solution.

This can be obtained as follow:

Molality = mole /kg of solvent

Mole of the unknown compound =.?

Mass of solvent = 10.30g = 10.30/1000 = 0.0103Kg

Molality = 0.45 M

Molality = mole /kg of solvent

0.45 = mole /0.0103

Cross multiply

Mole = 0.45 x 0.0103

Mole = 4.635×10¯³ mole

Therefore the mole of the unknown compound that dissolve in solution is 4.635×10¯³ mole

Now, we can obtain the molar mass of the unknown compound as follow:

Mole of the unknown compound = 4.635×10¯³ mole

Mass of unknown compound = 0.98g

Molar mass of the unknown compound =?

Mole = mass /Molar mass

4.635×10¯³ = 0.98 /Molar mass

Cross multiply

4.635×10¯³ x molar mass = 0.98

Divide both side by 4.635×10¯³

Molar mass = 0.98 / 4.635×10¯³

Molar mass = 211.4g/mol.

Therefore, the molar mass of the unknown compound is 211.4g/mol.

The molecular mass of the unknown has been 211.66 g/mol.

Molality can be defined as the moles of the solute per kg of solvent.

Molality can be expressed as:

Molality = [tex]\rm \dfrac{Mass\;of\;solute\;(g)}{molecular\;mass\;of\;solute}\;\times\;\dfrac{1000}{Mass\;of\;solvent\;(g)}[/tex] ......(i)

The given unknown has been the solute.

The mass of solute = 0.98 g.

The mass of solvent = 10.30 g.

The molality of the solution formed has been = 0.45 m.

Substituting the values in equation (i):

0.45 m = [tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}\;\times\;\dfrac{1000}{10.30\;g}[/tex]

0.45 m = [tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}\;\times\;97.087[/tex]

[tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}[/tex]  =  [tex]\rm \dfrac{0.45}{97.087}[/tex]

[tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}[/tex]  = 0.00463

Molecular mass of solute = [tex]\rm \dfrac{0.98}{0.00463}[/tex]

Molecular mass of solute = 211.66 g/mol.

The molecular mass of the unknown has been 211.66 g/mol.

For more information about the molality of the solution, refer to the link:

https://brainly.com/question/8103026

g A microwave oven heats by radiating food with microwave radiation, which is absorbed by the food and converted to heat. If the radiation wavelength is 12.5 cm, how many photons of this radiation would be required to heat a container with 0.250 L of water from a temperature of 20.0oC to a temperature of 99oC

Answers

Answer:

The total photons required = 5.19 × 10²⁸ photons

Explanation:

Given that:

the radiation wavelength λ= 12.5 cm = 0.125 m

Volume of the container = 0.250 L = 250 mL

The density of water = 1 g/mL

Density = mass /volume

Mass =  Volume ×  Density

Thus; the mass of the water =  250 mL ×  1 g/mL

the mass of the water = 250 g

the specific heat of water s = 4.18 J/g° C

the initial temperature [tex]T_1[/tex] = 20.0° C

the final temperature [tex]T_2[/tex] = 99° C

Change in temperature [tex]\Delta T[/tex] = (99-20)° C = 79 ° C

The heat q absorbed during the process = ms [tex]\Delta T[/tex]

The heat q absorbed during the process = 250 g × 4.18 J/g° C × 79° C

The heat q absorbed during the process = 82555 J

The energy of a photon can be represented by the equation :

= hc/λ

where;

h = planck's constant = [tex]6.626 \times 10^{-34} \ J.s[/tex]

c = velocity of light = [tex]3.0 \times 10^8 \ m/s[/tex]

=  [tex]\dfrac{6.626 \times 10^{-34} \times 3.0 \times 10^8}{0.125}[/tex]

= [tex]1.59024 \times 10^{-24}[/tex] J

The total photons required = Total heat energy/ Energy of a photon

The total photons required = [tex]\dfrac{82555 J}{1.59024 \times 10^{-24}J}[/tex]

The total photons required = 5.19 × 10²⁸ photons

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