the internal energy of an ideal gas depends only on its temperature. Do a first-law analysis of this process. A sample of an ideal gas is allowed to expand at constant temperature against atmospheric pressure.

Answers

Answer 1

Answer:

Check Explanation

Explanation:

The Mathematical expression of the first law is given as

ΔU = Q - W

Note that depending on convention, the mathematical expression for the first law can be written as

ΔU = Q + W

a) Yes, the gas does work on its surroundings. Since it expands; indicating that there is a change in volume.

The work done is given as -PΔV if we are using the convention of (ΔU = Q + W). And this work is negative work done, since the system expands and does work on the surroundings.

But if we are using the convention of (ΔU = Q - W), the work done is given as PΔV and the workdone by the system on the environment is positive work during expansion.

b) Since this all takes place at constant temperature and against a constant atmospheric pressure, the change in internal energy for this system is 0. Change in internal energy depends on a change in temperature.

So, from the mathematical expression,

ΔU = Q + W or ΔU = Q - W

If ΔU = 0,

Q = - W or Q = W

But either ways,

Q = PΔV

(because, W = -PΔV for ΔU=Q+W and W = PΔV for ΔU=Q-W)

So, either ways, the heat transfer is the same and it is positive. This indicates heat is transferred from the surroundings to the system.

(c) What is ΔU for the gas for this process?

Since this all takes place at constant temperature and against a constant atmospheric pressure, the change in internal energy for this system is 0. Change in internal energy depends on a change in temperature.

Hope this Helps!!!

Answer 2

Based on the given question, we can state that Yes, the gas does work on its surroundings because it expands, this shows that there is a change in volume.

Based on the second question, we can state that because this takes place at constant temperature and against a constant atmospheric pressure, then the change in internal energy for this system is zero.

Based on the third question, we can see that the ΔU for the gas for this process is zero because of the constant temperature and atmospheric pressure.

The Mathematical expression of the first law

This is given as

ΔU = Q - W

Hence, from the mathematical expression,

ΔU = Q + W or ΔU = Q - WIf ΔU = 0,Q = - W or Q = W

Regardless,

Q = PΔV

This means that the heat transfer remains the same and is positive

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Related Questions

At 25 oC the solubility of lead(II) chloride is 1.59 x 10-2 mol/L. Calculate the value of Ksp at this temperature. Give your answer in scientific notation to 2 SIGNIFICANT FIGURES (even though this is strictly incorrect). [a]

Answers

Answer:

The Ksp at 25°C is 1.6 * 10^-5

Explanation:

Step 1: Data given

Temperature = 25°C

Solubility of lead(II) chloride = 1.59 * 10^-2 mol/L

Step 2: The balanced equation

PbCl2(s) <===> Pb2+(aq) + 2Cl-(aq)

Step 3: Calculate the Ksp

Ksp = [Pb2+][Cl-]²

Ksp = [Pb2+][Cl-]²

[Pb2+] = 1.59 *10-2  = 0.0159 M

[Br-] = 2 x 1.59*10-2 = 3.18 *10-2 M

Ksp = (1.59*10-2)(3.18*10-2)²

Ksp =1.6 * 10^-5

The Ksp at 25°C is 1.6 * 10^-5

The value of solubility constant (Ksp) at 25°C in scientific notation is 1.6 × 10-⁵.

How to calculate solubility constant?

According to this question, the following parameters are given:

Temperature = 25°CSolubility of lead(II) chloride = 1.59 × 10-² mol/L

The balanced equation is as follows:

PbCl2(s) <==> Pb2+(aq) + 2Cl-(aq)

The solubility constant can be calculated as follows:

Ksp = [Pb2+][Cl-]²

Ksp = [Pb2+][Cl-]²

[Pb2+] = 1.59 × 10-² = 0.0159 M

[Br-] = 2 x 1.59*10-² = 3.18 × 10-² M

Ksp = (1.59 × 10-²)(3.18 × 10-²)²

Ksp =1.6 × 10-⁵

Therefore, the solubility constant (Ksp) at 25°C is 1.6 × 10-⁵.

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Combustion of hydrocarbons such as decane () produces carbon dioxide, a "greenhouse gas." Greenhouse gases in the Earth's atmosphere can trap the Sun's heat, raising the average temperature of the Earth. For this reason there has been a great deal of international discussion about whether to regulate the production of carbon dioxide. 1. Write a balanced chemical equation, including physical state symbols, for the combustion of liquid decane into gaseous carbon dioxide and gaseous water. 2. Suppose of decane are burned in air at a pressure of exactly and a temperature of . Calculate the volume of carbon dioxide gas that is produced. Round your answer to significant digits.

Answers

The missing part of the question is shown in the image attached

Answer:

C10H22(l) + 31/2 O2 (g)-----> 10CO2(g) + 11H2O(l)

V= 70.4L of CO2

Explanation:

Equation of the reaction is:

C10H22(l) + 31/2 O2 (g)-----> 10CO2(g) + 11H2O(l)

Number of moles of decane = mass/ molar mass

Molar mass of decane= 122gmol-1

n= 0.370×10^3g/122gmol-1= 3.0 moles

T= 13°C +273=286K

P= 1atm

R= 0.082 atmLK-1mol-1

From :

PV= nRT

V= nRT/P

V= 3.0×0.082×286/1

V= 70.4L of CO2

The balanced chemical equation for the combustion of liquid decane [tex](C\_{10}H\_{22}\))[/tex] into gaseous carbon dioxide [tex](CO\_{2}\)[/tex]and gaseous water [tex](H\_{2}O\) is: \[ 2C_{10}H_{22(l)} + 31O_{2(g)} \rightarrow 20CO_{2(g)} + 22H_2O_{(g)} \][/tex]

To calculate the volume of carbon dioxide gas produced when 0.500 moles of decane are burned, we use the stoichiometry of the balanced equation and Avogadro's law, which states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules (or moles). From the balanced equation, 1 mole of decane produces 20 moles of CO\_{2}\. Therefore, 0.500 moles of decane will produce:

[tex]\[ 0.500 \text{ moles } C_{10}H_{22} \times \frac{20 \text{ moles } CO_2}{2 \text{ moles } C_{10}H_{22}} = 5.00 \text{ moles } CO_2 \][/tex]

According to Avogadro's law, at the same temperature and pressure, the volume of a gas is directly proportional to the number of moles of the gas. Since the pressure and temperature are not specified in the question, we cannot calculate the exact volume of CO\_{2}\ produced. However, if we assume standard temperature and pressure (STP) conditions, where 1 mole of an ideal gas occupies 22.414 liters, the volume of CO\_{2}\ produced would be:

[tex]\[ 5.00 \text{ moles } CO_2 \times \frac{22.414 \text{ L}}{1 \text{ mole } CO_2} = 112.07 \text{ L} \][/tex]

Since the question specifies that the pressure is exactly 1 atmosphere but does not specify the temperature, we cannot use the value of 22.414 L/mol for the molar volume of CO\_{2}\. We need the temperature to determine the molar volume of CO\_{2}\ at that specific condition. If the temperature is also at STP (0°C or 273.15 K), then the volume calculated above is correct. If the temperature is different, we would need to use the ideal gas law, PV = nRT, to find the volume V, where P is the pressure, n is the number of moles of gas, R is the ideal gas constant, and T is the temperature in Kelvin.

Since the temperature is not provided, we can only provide the volume of [tex]CO\_{2}\[/tex] at STP, which is 112.07 L, rounded to four significant digits as 112.1 L. If the temperature were provided, we would use the ideal gas law to calculate the volume at that specific temperature and pressure.

A rectangular corral of widths Lx = L and Ly = 2L contains seven electrons. What is the energy of (a) the first excited state, (b) the second excited state, and (c) the third excited state of the system? Assume that the electrons do not interact with one another, and do not neglect spin. State your answers in terms of the given variables, using h and me (electron mass) when needed.

Answers

Answer:

See explaination

Explanation:

The invariant mass of an electron is approximately9. 109×10−31 kilograms, or5. 489×10−4 atomic mass units. On the basis of Einstein's principle of mass–energy equivalence, this mass corresponds to a rest energy of 0.511 MeV.

Check attachment for further solution to the exercise.

AB2 is a molecule that reacts readily with water. Calculate the bond energy of the A–B bond using the standard enthalpy of reaction and the bond energy data provided. Enter a number in kJ to 0 decimal places. 2AB2(g) + 2H2O(g) ⟶ O=O(g) + 4HB(g) + A2 ΔH° = –142 kJ

Answers

Given question is incomplete. The complete question is as follows.

[tex]AB_{2}[/tex] is a molecule that reacts readily with water. Calculate the bond energy of the A–B bond using the standard enthalpy of reaction and the bond energy data provided. Enter a number in kJ to 0 decimal places.

  [tex]2AB_{2}(g) + 2H_{2}O(g) \rightarrow O=O(g) + 4HB(g) + A_{2}[/tex] [tex]\Delta H^{o}[/tex] = –142 kJ

Bond:                             O–H          O=O           H–B    [tex]A \rightarrow A^{+}[/tex]

Bond energy (kJ/mol):   467         498           450         321      

Explanation:

The given reaction is as follows.

         [tex]2AB_{2} + 2H_{2}O \rightarrow O_{2} + 4HB + A_{2}[/tex]

Now, we will calculate the enthalpy of reaction as follows.

   [tex]\Delta H^{o}_{R}[/tex] = -142 kJ

Also, we know that

   [tex]\Delta H^{o}_{R} = \Delta H_{reactants} - \Delta H_{products}[/tex]

                  = [tex][(2 \times 2 (A-B) + 2 \times 2 (O-H)] - [(O=O) + 4(H-B) + (A-A)][/tex]

         -142 = [tex]4(A-B) + 4 \times 467 - 498 - 4(450) - 321[/tex]

    [tex]4(A-B)[/tex] = -142 - 1868 + 498 + 1800 + 321

                    = 609

          (A-B) = 152.25 kJ/mol

Thus, we can conclude that the bond energy of the A–B bond is 152.25 kJ/mol.

A single-effect evaporator is concentrating a feed of 9072 kg/h of a 10 wt % solution of NaOH in water at temperature of 288.8 K to a product of 50% solids. The pressure of the saturated steam used is 42 kPa (gage) and the pressure in the vapor space of the evaporator is 20 kPa (abs).



a)Neglecting boiling point raise and the heat of solution, calculate the steamused, the steam economy in kg vaporized/kg steam, required surface area ofthe evaporator.



b)Repeat the calculations taking into consideration boiling point raise and heatof solution

Answers

Answer:

Check the explanation

Explanation:

Going by the question above for parta, the feed flow rate is stated to be 9072g/hr.& result is offered for part a considering the same. if the unit is kg/hr, then kindly let me know & i shall make slight modification that might be required in solution which in that case, area & steam consumption answer shall differ.

In the b part of the question, reduced flow rate is higher than the initial flow rate therefore same has been considered in gram /hr.

Kindly check the attached images below to see the step by step solution to the above question.

In this exercise we have to use the knowledge of mechanics to calculate the steamused of the solution, in this way we will have to:

a) [tex]M_S=\frac{H_S}{\lambda_S} = 8.43 KG/h[/tex] , [tex]A= 0.0526 m^2[/tex]

b) We can assume that all water shall evaporate and produd shell contain solid only.

So from the data informed in the exercise we have that:

[tex]F= 9072 g/h[/tex][tex]M_f=907,2 g/h[/tex][tex]M_L=1814.4 kg/h=L[/tex]

So apply overall mass balance, will be:

[tex]F=L+V\\9072=1814.4-V\\V=7.2576 kg/h[/tex]

Now, for enthalpy balance we shall make assumption that, all liquid phase enthalphy is that heet capacity of water is constant, so the data will be:

[tex]C=4.18 kJ/kg[/tex][tex]T_c=15.6[/tex][tex]P=20KPa[/tex][tex]T_P=60[/tex]

So, find the enthalpy of liquid, we have;

[tex]H_L= L*C_P*(T_P-T_F)\\=(1.8144)(4.18)(60.0586-15.6)\\H_v=V*(P(t_P-T_F)+\lambda)\\=(7.2576)(4.18(60.0586-15.6)+2357.5477))H_s=H_L+H_V\\H_S= (1.8144)(4.18)(60.0586-15.6)+(7.2576)(4.18(60.0586-15.6)+2357.5477))\\=18796.051 KJ/h[/tex]

Now, we can find the mass flow rate, that will be;

[tex]M_S=\frac{H_S}{\lambda_S} = 8.43 KG/h[/tex]

Now we can find the area of evaporator, that will be:

[tex]H_S=UA=(T_S-T_P)\\A=0.0526m^2[/tex]

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A 25.0 mL sample of a 0.100 M solution of acetic acid is titrated with a 0.125 M solution of NaOH. Calculate the pH of the titration mixture after 10.0, 20.0, and 30.0 mL of base have been added. The Ka for acetic acid is 1.76×10–5.

Answers

Explanation:

10mil 76 the experllon is the most numbers

Answer:

Ater adding 10.0 mL the pH = 4.74

After adding 20.0 mL the pH = 8.75

After adding 30.0 mL the pH = 12.36

Explanation:

Step 1: Data given

Volume of a 0.100 M acetic acid solution = 25.0 mL

Molarity of NaOH solution = 0.125 M

A) 25.0mL of HAc(acetic acid) and 10.0mL of NaOH

Calculate moles

Equation:   NaOH    +   HAc    -->   NaAc + H20

Moles HAc =  0.025 L*  0.100 mol /L = 0.00250 moles

Moles NaOH = 0.01 L * 0.125mol/L = 0.00125 moles

Initial moles

NaOH = 0.00125 moles

HAc = 0.00250 moles

NaAC = 0 moles

Moles at the equilibrium

NaOH = 0.00125 - 0.00125 = 0 moles

HAc = 0.00250 - 0.00125 = 0.00125 moles

NaAC = 0.00125 moles

Calculate molarity

[HAc] = [Ac-] =  0.00125 moles / 0.035 L = 0.0357M

Concentration at equilibrium

HAc   <--> Ac-     +  H+         Ka = 1.76 * 10^-5

[HAc] = 0.0357 - x M

[Ac-] = 0.0357 + X M

[H+] = XM

Ka=1.76*10^-5 = [Ac-][H+]/[HAc] = [0.00357+x][x]/[0.00357-x]

Ka=1.76*10^-5 = [0.00357][x]/[0.0357] usually good approx.

Ka = 1.76* 10-5 = x = [H+]

pH = -log [H+] = -log [1.76*10^-5] = 4.74

B) 25.0mL HAc and 20.0mL NaOH

Calculate moles

Equation:   NaOH    +   HAc    -->   NaAc + H20

Moles HAc =  0.025 L*  0.100 mol /L = 0.00250 moles

Moles NaOH = 0.02 L * 0.125mol/L = 0.00250 moles

Initial moles

NaOH = 0.00250 moles

HAc = 0.00250 moles

NaAC = 0 moles

Moles at the equilibrium

NaOH = 0.00250 - 0.00250 = 0 moles

HAc = 0.00250 - 0.00250 = 0 moles

NaAC = 0.00250 moles

Calculate molarity

[NaAC] =  0.00250 moles / 0.045 L = 0.0556M

Concentration at equilibrium

Ac- + H20   <--> HAc     +  OH-        Ka = 1.76 * 10^-5

[Ac] = 0.0556 - x M

[OH-] = XM

[HAc] = XM

**Kw = 1*10^-14 at STP I'll assume this for this problem

**Kw = Ka*Kb ⇒ Kb = Kw/Ka

**Kb = (1*10^-14)/(1.76*10^-5)= 5.68*10^-10  

Kb = ([HAc][OH-])/[Ac-] =  ([x][x])/[0.0556]

Kb =  x² /0.0556

5.68*10^-10 = x² /0.0556

so x =5.62*10^-6

pOH = -log [OH-] = 5.250

pH = 14 - pOH

pH 14 - 5.25 = 8.75

C)25.0mL HAc and 30.0mL NaOH

NaOH    +   HAc    -->   NaAc + H20

Initial numbers of moles

Moles NaOH = 0.125M * 0.03 L = 0.00375 moles

Moles HAc =  0.00250 moles

moles NaAC = 0 moles

Moles at the equilibrium

Moles NaOH = 0.00375 moles - 0.00250 = 0.00125 moles

Moles HAc =  0.00250 moles - 0.00250 = 0 moles

moles NaAC = 0.00250 moles

After the reaction there is some NaOH left over so it is the only thing that matters for the pH as it is a stong base.

Calculate NaOH molarity

(0.00125moles/0.055 L= 0.0227M NaOH

Strong Bases dissociate 100% so [OH-] = 0.0227M

pOH= -log[0.0227] = 1.644

pH = 14-pOH = 12.36

There are three voltaic cells. In each voltaic cell one half-cell contains a 1.0 M Fe(NO3)2(aq) solution with an Fe electrode. The contents of the other half-cells are as follows:Cell 1: a 1.0 M CuCl2(aq) solution with a Cu electrodeCell 2: a 1.0 M NiCl2(aq) solution with a Ni electrodeCell 3: a 1.0 M ZnCl2(aq) solution with a Zn electrodeIn which voltaic cell(s) does iron act as the anode?a)Cell 1b)Cell 2c)Cell 3d)Cells 1 and 2e)All three cells

Answers

Answer:

d)Cells 1 and 2

Explanation:

In a voltaic cell, oxidation occurs at the anode and reduction occurs at the cathode. The half cell that function as anode or cathode in a voltaic cell depends strictly on the reduction potential of the metal ion/metal system in that half cell.

Examining the reduction potentials of the various metal ion/metal systems in the three half cells;

Cu= +0.34 V

Ni= -0.25 V

Zn= -0.76 V

Fe(Fe2+)= -0.44 V

Hence only Zn2+ has a more negative reduction potential than Fe2+. The more negative the reduction potential, the greater the tendency of the system to function as the anode. Thus iron half cell will function as anode in cells 1&2 as explained in the argument above.

The correct answer is e) All three cells.

To determine in which voltaic cell(s) iron acts as the anode, we need to compare the standard reduction potentials (E°) of the half-reactions involved in each cell. The half-reaction for iron in all three cells is:

[tex]\[ \text{Fe}^{2+}(aq) + 2e^- \rightarrow \text{Fe}(s) \quad \text{with} \quad E_{\text{Fe}^{2+}/\text{Fe}}^\circ = -0.44 \, \text{V} \][/tex]

Now, let's consider the half-reactions for the other metals in each cell:

Cell 1:

[tex]\[ \text{Cu}^{2+}(aq) + 2e^- \rightarrow \text{Cu}(s) \quad \text{with} \quad E_{\text{Cu}^{2+}/\text{Cu}}^\circ = +0.34 \, \text{V} \][/tex]

Cell 2:

[tex]\[ \text{Ni}^{2+}(aq) + 2e^- \rightarrow \text{Ni}(s) \quad \text{with} \quad E_{\text{Ni}^{2+}/\text{Ni}}^\circ = -0.25 \, \text{V} \][/tex]

Cell 3:

[tex]\[ \text{Zn}^{2+}(aq) + 2e^- \rightarrow \text{Zn}(s) \quad \text{with} \quad E_{\text{Zn}^{2+}/\text{Zn}}^\circ = -0.76 \, \text{V} \][/tex]

In a voltaic cell, the metal with the more negative standard reduction potential (or less positive) will act as the anode, and the metal with the more positive standard reduction potential will act as the cathode.

Comparing the standard reduction potentials:

- For Cell 1, [tex]\( E_{\text{Cu}^{2+}/\text{Cu}}^\circ > E_{\text{Fe}^{2+}/\text{Fe}}^\circ \)[/tex], so iron has a more negative potential than copper, and iron will act as the anode.

- For Cell 2, \[tex]( E_{\text{Ni}^{2+}/\text{Ni}}^\circ > E_{\text{Fe}^{2+}/\text{Fe}}^\circ \)[/tex], so iron has a more negative potential than nickel, and iron will act as the anode.

- For Cell 3, [tex]\( E_{\text{Zn}^{2+}/\text{Zn}}^\circ < E_{\text{Fe}^{2+}/\text{Fe}}^\circ \)[/tex], so zinc has a more negative potential than iron, and iron will act as the cathode.

However, this last comparison is incorrect because we must consider the sign of the standard reduction potentials. Since both zinc and iron have negative standard reduction potentials, the metal with the less negative value (in this case, iron) will act as the anode, and the metal with the more negative value (zinc) will act as the cathode.

Therefore, iron acts as the anode in all three cells, which corresponds to option e) All three cells.

Name the following compound:
(ignore the dots, I tried to space them out but it wouldn't let me)
........... O
.............ll
CH3 - C - CH2 - CH2 - CH2 - CH3



Methyl butanone

2-hexanol

2-hexanone

Methyl butyl ether

Answers

Answer:

2-hexanone

Explanation:

First, we'll begin by:

1. Locating the longest continuous chain i.e haxane

2. Determine the functional group in the compound. The functional group in ketone (C=O). This changes the name from hexane to hexanone i.e replacing the -e in at the end in hexane with -one to make it hexanone.

3. Give the functional group the lowest low count. In doing this, we'll start counting from the left. The functional group is at carbon 2.

Note: no substitute group is attached.

Now, in naming the compound, we must indicate the position of functional group as illustrated below:

The name of the compound is:

2-hexanone

Final answer:

The compound is called 2-hexanone. This is because there is a six carbon chain with a ketone functional group attached to the second carbon.

Explanation:

You are dealing with an organic compound formula. Let's identify the compound based on its structure. The compound you have given is CH3 - C - CH2 - CH2 - CH2 - CH3. This is a 6 carbon chain and there is double bond between Oxygen and the second carbon. Now, when naming compounds in chemistry we firstly count the length of the chain, it is hexane. Then, we look for any functional group and where it is attached in the chain. A ketone functional group is CO, so this would make it a hexanone. As the CO is attached at the second carbon, it is 2-hexanone. So the correct answer for the name of the compound would be 2-hexanone.

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Determine the value of Kc for the following reaction if the equilibrium concentrations are as follows: [H2]eq = 0.14 M, [Cl2]eq = 0.39 M, [HCl]eq = 1.6 M. H2(g) + Cl2(g) ⇌ 2 HCl(g) Determine the value of Kc for the following reaction if the equilibrium concentrations are as follows: [H2]eq = 0.14 M, [Cl2]eq = 0.39 M, [HCl]eq = 1.6 M. H2(g) + Cl2(g) ⇌ 2 HCl(g) 12 29 2.1 × 10-2 8.7 × 10-2 47

Answers

Question:

A) 12

B) 29

C) 2.1 × 10⁻²

D) 8.7 × 10⁻²

E) 47

Answer:

The correct option is;

E) 47

Explanation:

Kc, which is the equilibrium constant of a chemical reaction is derived by finding the ratio between the product of the equilibrium concentration of the product raised to their respective coefficients to the product of the equilibrium concentration of the reactants also raised to their respective coefficients.

Here we have;

[H₂] = 0.14 M

[Cl₂] = 0.39 M

[HCl] = 1.6

The reaction is given as follows;

H₂ (g) + Cl₂ (g) ⇄ 2HCl (g)

The formula for Kc is given as follows;

[tex]Kc = \frac{[HCl]^2}{[H_2][Cl_2]} = \frac{1.6^2}{0.14 \times 0.39} = 46.886[/tex]

Therefore, the Kc for the reaction is approximately equal to 47.

What mass of potassium bromide (in grams) do you need to make 250.0 mL of a 1.50 M potassium bromide solution?

Answers

Answer:

44.63g

Explanation:

First, let us calculate the number of mole of KBr in 1.50M KBr solution.

This is illustrated below:

Data obtained from the question include:

Volume of solution = 250mL = 250/1000 = 0.25L

Molarity of solution = 1.50M

Mole of solute (KBr) =.?

Molarity is simply mole of solute per unit litre of solution

Molarity = mole /Volume

Mole = Molarity x Volume

Mole of solute (KBr) = 1.50 x 0.25

Mole of solute (KBr) = 0.375 mole

Now, we calculate the mass of KBr needed to make the solution as follow:

Molar Mass of KBr = 39 + 80 = 119g/mol

Mole of KBr = 0.375 mole

Mass of KBr =?

Mass = number of mole x molar Mass

Mass of KBr = 0.375 x 119

Mass of KBr = 44.63g

Therefore, 44.63g of KBr is needed to make 250.0mL of 1.50 M potassium bromide (KBr) solution

Final answer:

To make a 1.50 M potassium bromide solution with a volume of 250.0 mL, you would need approximately 44.625 grams of potassium bromide.

Explanation:

To calculate the mass of potassium bromide required, we can use the formula:

mass (g) = concentration (M) x volume (L) x molar mass (g/mol)

The concentration is given as 1.50 M, the volume is 250.0 mL (which can be converted to 0.250 L), and the molar mass of potassium bromide (KBr) is 119.0 g/mol. Plugging in these values, we get:

mass (g) = 1.50 M x 0.250 L x 119.0 g/mol = 44.625 g

Therefore, you would need approximately 44.625 grams of potassium bromide to make 250.0 mL of a 1.50 M potassium bromide solution.

The surface of a solid sphere is covered by a monolayer of receptors for a ligand. When the ligands diffuse to the surface of the sphere, they are captured instantaneously by the receptors. The ligand diffusion coefficient is 5.2*10-9m2/s. Assume the bulk concentration far away from the sphere is constant of 6.6 nM and the sphere radius is 9.8 μm. (a) Find the ligand concentration C at the location of r=4.9 μm at steady state, where r is the distance to the surface of the sphere. Please enter the numerical value with a unit of nM.

Answers

Answer:

The ligand concentration C is 0.274 nM

Explanation:

According to the image, the bulk concentration is inversely proportional to the radius, thus:

[tex]B=\frac{B_{\alpha }r^{2} }{\alpha }[/tex]

Where

Bα = 6.6 nM

r = 14.7 um = 1.47x10⁻⁵m

[tex]B=\frac{6.6*(1.47x10^{-5})^{2} }{5.2x10^{-9} } =0.274nM[/tex]

What is the main greenhouse gas responsible for influencing the world climate

Answers

Answer:

carbon dioxide

Explanation:

Suppose that a heat engine operates with a hot source at a temperature of 485 oC and a cold sink at 42 oC. What is the maximum amount of work the engine is capable of performing if 9.75 kJ of heat are extracted from the hot source?

Answers

Answer:

W = - 10.5943 KJ, work is negative because it is carried out by the system towards the surroundings.

Explanation:

heat engine:

∴ Th = 485°C

∴ Tc = 42°C

∴ Qh = 9.75 KJ......heat from hot source

first law:

∴ ΔU = Q + W = 0 .........cyclic process

⇒ Q = - W

∴ Q = Qh + Qc = Qh - (- Qc)

∴ Qc: heat from the cold source ( - )

⇒ Qh - ( - Qc) = - W..............(1)

⇒ Qc/Qh = - Tc/Th...........(2)

from (2):

⇒ Qc = - (Tc/Th)(Qh) = - (42°C/485°C)(9.75 KJ)

⇒ Qc = - 0.8443 KJ

replacing in (1):

⇒ - W = 9.75 KJ - ( - 0.8443 KJ)

⇒ - W = 10.5943 KJ

Consider the following data on some weak acids and weak bases:

acid base

Ka name formula Kb name formula

6.8x10-4 hydrofluoric acid HF 1.8x10-5 ammonia NH3

4.9x10-10 hydrocyanic acid HCN 1.7x10-9 pyridine C5H5N

Use this data to rank the following solutions in order of increasing pH. In other words, select a '1' next to the solution that will have the lowest pH, a '2' next to the solution that will have the next lowest pH, and so on.

solution

a.0.1 M NaCN

b.0.1M NH4Br

c.0.1M KF

d.0.1M KBr

Answers

Answer:

See explaination

Explanation:

Please kindly check attachment for the step by step solution of the given problem.

Final answer:

The question involves ranking solutions of weak acids and bases by their pH. After assessing the ionization and hydrolysis of the compounds, the order from lowest to highest pH is 0.1 M NH4Br, 0.1 M NaCN, 0.1 M KF, and 0.1 M KBr.

Explanation:

To rank the solutions in order of increasing pH, we must consider the ionization of each compound in water and the corresponding Ka or Kb values. A lower Ka or a higher Kb value usually results in a higher pH.

0.1 M KF: KF will form from the dissolution of a weak acid (HF) and a strong base. The resulting F- ions will hydrolyze to form OH- ions, creating a basic solution with a pH higher than 7 but not as high as that of a strong base.

Therefore, the order from lowest to highest pH should be b, a, c, d.

Combustion of hydrocarbons such as nonane (CoH20) produces carbon dioxide, a "greenhouse gas." Greenhouse gases in the Earth's atmosphere can trap the Sun's heat, raising the average temperature of the Earth. For this reason, there has been a great deal of international discussion about whether to regulate the production of carbon dioxide. 1. Write a balanced chemical equation, including physical state symbols, for the combustion of liquid nonane into gaseous carbon dioxide and gaseous water. Suppose 0.130 kg of nonane are burned in the air at a pressure of exactly 1 atm and a temperature of 12.0 °C. Calculate the volume of carbon dioxide gas that is produced Be sure your answer has the correct number of significant digits.

Answers

Answer:

1. C9H20(l) + 14O2(g) —> 9CO2(g) + 10H2O(g)

2. 213.70L of CO2

Explanation:

1. The equation for the combustion of liquid nonane into gaseous carbon dioxide and gaseous water is given below:

C9H20(l) + O2(g) —> CO2(g) + H2O(g)

The equation can be balanced as follow:

There are 9 atoms of C on the left side and 1 atom on the right side. It can be balance by putting 9 in front of CO2 as shown below:

C9H20(l) + O2(g) —> 9CO2(g) + H2O(g)

There are 20 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 10 in front of H2O as shown below:

C9H20(l) + O2(g) —> 9CO2(g) + 10H2O(g)

Now, there are a total of 28 atoms of O on the right side and 2 atoms on the left side. It can be balance by putting 14 in front of O2 as shown below:

C9H20(l) + 14O2(g) —> 9CO2(g) + 10H2O(g)

Now the equation is balanced.

2. Let us convert 0.130 kg of nonane (C9H20) to mole. This is illustrated below:

Molar Mass of C9H20 = (12x9) + (20x1) = 108 + 20 = 128g/mol

Mass of C9H20 from the question =

0.130kg = 0.130 x 1000 = 130g

Mole of C9H20 =?

Number of mole = Mass/Molar Mass

Mole of C9H20 = 130/128 = 1.016 mole

The equation for the reaction is:

C9H20(l) + 14O2(g) —> 9CO2(g) + 10H2O(g)

From the balanced equation above,

1 mole of C9H20 produced 9 moles of CO2.

Therefore, 1.016 mole of C9H20 will produce = 1.016 x 9 = 9.144 moles

Now, let us calculate the volume of CO2 formed. This is illustrated below:

Data obtained from the question include:

P (pressure) = 1atm

T (temperature) = 12°C = 285K

n (number of mole of CO2) = 9.144 moles

R (gas constant) = 0.082atm.L/Kmol

V (volume of CO2) =?

Using the ideal gas equation PV = nRT, the volume of CO2 can be obtained as follow:

PV = nRT

1 x V = 9.144 x 0.082 x 285

V = 213.70L

Therefore, 213.70L of CO2 is produced

Final answer:

The combustion of nonane, C9H20(l) + 14O2(g) → 9CO2(g) + 10H2O(g), produces carbon dioxide and water. Using stoichiometry and the ideal gas law, the volume of carbon dioxide produced from 0.130 kg of nonane is calculated to be approximately 216.5 L.

Explanation:

The first step is to write a balanced chemical equation for the combustion of nonane. The complete combustion of hydrocarbons, like nonane, in the presence of oxygen (O2) yields carbon dioxide (CO2) and water (H2O). The correct balanced equation is:

C9H20(l) + 14O2(g) → 9CO2(g) + 10H2O(g).

To calculate the volume of carbon dioxide produced from the amount of nonane combusted, one must apply the concepts of stoichiometry and gas laws. According to the equation, 9 moles of CO2 is produced from 1 mole of nonane. As the molar mass of nonane is 128.26 g/mol, 0.130 kg or 130 g of nonane is approximately 1.013 moles. Therefore, we will have around 9.117 moles of carbon dioxide produced.

Applying the ideal gas law, PV = nRT, at standard temperature (12°C = 285.15 K) and pressure (1 atm), and R = 0.0821 L.atm / K.mol, we can calculate the volume as V = nRT/P. The volume of CO2 produced would be approximately 216.5 L, with correct significant digits.

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A saturated solution of manganese(II) hydroxide was prepared, and an acid–base titration was performed to determine its KspKsp at 25 °C. The endpoint was reached when 70.00 mLmL of the manganese(II) hydroxide solution was titrated with 4.86 mLmL of 0.0020 MM HClHCl solution. What is the KspKsp of manganese(II) hydroxide?

Answers

Final answer:

The Ksp of Mn(OH)2 at 25°C is found to be 1.07 x 10^-11 M by analyzing the acids and bases reaction via titration using 0.002M HCl solution.

Explanation:

The subject question deals with an acid-base titration procedure to determine the solubility product constant, Ksp, of manganese(II) hydroxide at 25°C. The concentration of HCl used for titration is 0.002M and it completely reacts with manganese(II) hydroxide in 70.00mL of solution. The molarity of Mn(OH)2 in the saturated solution can be calculated as (0.002M * 4.86mL) / 70.00mL = 1.388 x 10^-4 M.

Since each Mn(OH)2 gives one Mn²⁺ and two OHˉ ions when dissolved, the molarity of OH- ions will be twice that of Mn(OH)2. Therefore, the OH- ion molarity is 2 * 1.388 x 10^-4 M = 2.776 x 10^-4 M.

The Ksp of Mn(OH)2 can be calculated as [Mn²⁺][OHˉ]² = (1.388 x 10^-4 M) * (2.776 x 10^-4 M)² = 1.07 x 10^-11 M. Thus, we can conclude that the Ksp of manganese(II) hydroxide at 25°C is approximately 1.07 x 10^-11 M.

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How many grams of lithium sulfate are required to make 2500 mL of a 2.67 M solution of lithium sulfate? *
A. 248 g
B. 734 g
C. 527 g
D. 812 g

Answers

Answer:

The correct answer is B. 734 g

Explanation:

The chemical formulae of lithium sulfate is Li₂SO₄. With this, we can calculate the molecular weight (MM) of lithium sulfate as follows:

MM(Li₂SO₄) = (2 x molar mass Li) + molar mass S + (4 x molar mass O)

                   = (2 x 6.9 g/mol) + 32 g/mol + (4 x 16 g/mol)

                   = 109.9 g/mol

We need to prepare a solution with a molarity of 2.67 M. That means that the solution has to have 2.67 moles of Li₂SO₄ per liter of solution. We can convert from mol to grams with the calculated molecular weight and then we have to multiply by the volume of solution (2500 ml= 2.5 L), as follows:

Mass = 2.67 mol/L x 109.9 g/mol x 2.5 L ≅ 734 g

A gas occupies a volume of 30.0L, a temperature of 25°C and a pressure of 0.600atm. What will be the volume of the gas at STP?​

Answers

Answer:

=16.49 L

Explanation:

Using the equation

P1= 0.6atm V1= 30L, T1= 25+273= 298K, P2= 1atm, V2=? T2= 273

P1V1/T1= P2V2/T2

0.6×30/298= 1×V2/273

V2=16.49L

write a balanced equation for the reaction between dichromate Ion and iron 2 to yield iron 3 and chromium 3 in acidic solution Cr2O72- + Fe2+ -> Cr3+ + Fe3+​

Answers

Answer:

Cr2O72- + 5Fe2+ +14H+ -> 2Cr3+ + 5Fe3+ +7H2O

Explanation:

Fe2+ is oxidized to Fe3+ and Cr6+ is reduced to Cr3+

Final answer:

Explains the balanced redox reaction between dichromate ion and iron(II) to yield iron(III) and chromium(III) in acidic solution.

Explanation:

Balanced Equation: 7H₂O(l) + 6Fe²+(aq) + Cr₂O72-(aq) → 6Fe³+(aq) + 2Cr³+(aq) + 14H+(aq)

Explanation: The reaction between dichromate ion and iron(II) to yield iron(III) and chromium(III) in acidic solution is represented by this balanced redox equation. By balancing the atoms and charges on both sides, the equation shows the transformation of Fe²+ to Fe³+ and Cr2O7²- to Cr³+.

Example: In a similar process, Cr atoms are oxidized to form Cr³+ while Fe atoms are reduced to Fe³+, showcasing the transfer of electrons in the redox reaction.

Given the thermochemical equations below, What is the standard heat of formation of CuO(s)? 2 Cu2O(s) + O2(g) ---> 4 CuO(s) ∆H° = -287.9 kJ Cu2O(s) ---> CuO(s) + Cu(s) ∆H° = 11.3 kJ

Answers

The standard heat of formation of [tex]\( \text{CuO(s)} \) is \( -149.6 \text{ kJ/mol} \).[/tex]

To find the standard heat of formation of [tex]\( \text{CuO(s)} \)[/tex], we can use the given thermochemical equations and apply Hess's Law.

Given Equations:

1. [tex]\( 2 \text{Cu}_2\text{O(s)} + \text{O}_2\text{(g)} \rightarrow 4 \text{CuO(s)} \quad \Delta H^\circ = -287.9 \text{ kJ} \)[/tex]

2. [tex]\( \text{Cu}_2\text{O(s)} \rightarrow \text{CuO(s)} + \text{Cu(s)} \quad \Delta H^\circ = 11.3 \text{ kJ} \)[/tex]

Goal:

Find the standard heat of formation of [tex]\( \text{CuO(s)} \), \( \Delta H_f^\circ \text{(CuO(s))} \).[/tex]

Steps:

1. Write the formation reaction for [tex]\( \text{CuO(s)} \)[/tex]

[tex]\[ 2 \text{Cu(s)} + \text{O}_2\text{(g)} \rightarrow 2 \text{CuO(s)} \][/tex]

2. Manipulate the given equations to match the formation reaction:

a. Reverse Equation 2 to get [tex]\( \text{CuO(s)} \) and \( \text{Cu(s)} \)[/tex] on the reactant side:  

[tex]\[ \text{CuO(s)} + \text{Cu(s)} \rightarrow \text{Cu}_2\text{O(s)} \quad \Delta H^\circ = -11.3 \text{ kJ} \][/tex]

b. Add this to Equation 1 (which needs no change) to eliminate[tex]\( \text{Cu}_2\text{O(s)} \): \[ \begin{align*} \text{CuO(s)} + \text{Cu(s)} &\rightarrow \text{Cu}_2\text{O(s)} \quad \Delta H^\circ = -11.3 \text{ kJ} \\ 2 \text{Cu}_2\text{O(s)} + \text{O}_2\text{(g)} &\rightarrow 4 \text{CuO(s)} \quad \Delta H^\circ = -287.9 \text{ kJ} \\ \end{align*} \][/tex]

Adding these equations:

[tex]\[ \text{CuO(s)} + \text{Cu(s)} + 2 \text{Cu}_2\text{O(s)} + \text{O}_2\text{(g)} \rightarrow \text{Cu}_2\text{O(s)} + 4 \text{CuO(s)} \][/tex]

Simplify:

[tex]\[ 2 \text{Cu(s)} + \text{O}_2\text{(g)} \rightarrow 2 \text{CuO(s)} \][/tex]

3. Combine the enthalpy changes:

[tex]\[ \Delta H^\circ = -287.9 \text{ kJ} + (-11.3 \text{ kJ}) = -299.2 \text{ kJ} \][/tex]

Since the above reaction is for 2 moles of [tex]\( \text{CuO(s)} \)[/tex], the enthalpy change for the formation of 1 mole of [tex]\( \text{CuO(s)} \)[/tex] is:

[tex]\[ \Delta H_f^\circ \text{(CuO(s))} = \frac{-299.2 \text{ kJ}}{2} = -149.6 \text{ kJ/mol} \][/tex]

During lab, a student used a Mohr pipet to add the following solutions into a 25 mL volumetric flask. They calculated the final volumes added, which are recorded below. The student then followed the directions in the manual to make the stock solution. Volumes Used to Create Stock Solution Volume 0.200 M Fe(NO3)3 (mL) Volume 0.00200 M KSCN (mL) Stock Solution 10.63 mL 1.42 mL Using the stock solution above, the student made additional dilutions, with the final volumes below. Calculate the [FeSCN2 ] in Standard 2. Report your answer in mM. Volumes Used to Create Standard Solutions Solution Volume Stock solution (mL) Volume Water (mL) Standard 1 7.43 2.53 Standard 2 4.63 5.17 Standard 3 2.66 6.58 Standard 4 0.57 9.36 Note: Reporting your answer in mM is for grading purposes only. It is not necessary during lab. Report your answer to three places after the decimal.

Answers

Answer:

(FeSCN⁺²) = 0.11 mM

Explanation:

Fe ( NO3)3 (aq) [0.200M] + KSCN (aq) [ 0.002M] ⇒ FeSCN+2

M (Fe(NO₃)₃  = 0.200 M

V (Fe(NO₃)₃ =  10.63 mL

n (Fe(NO₃)₃ = 0.200*10.63 = 2.126 mmol

M (KSCN) =  0.00200 M

V (KSCN) = 1.42 mL

n (KSCN) =  0.00200 * 1.42 = 0.00284 mmol

Total volume = V (Fe(NO₃)₃  + V (KSCN)

                       = 10.63 + 1.42

                       = 12.05 mL

Limiting reactant = KSCN

So,

FeSCN⁺² = 0.00284 mmol

M (FeSCN⁺²) = 0.00284/12.05

                     = 0.000236 M

Excess reactant = (Fe(NO₃)₃

n(Fe(NO₃)₃ =  2.126 mmol -  0.00284 mmol

                  =2.123 mmol

For standard 2:

n (FeSCN⁺²) = 0.000236 * 4.63

                    =0.00109

V(standard 2) = 4.63 + 5.17

                       = 9.8 mL

M (FeSCN⁺²)  = 0.00109/9.8

                      = 0.000111 M = 0.11 mM

Therefore, (FeSCN⁺²) = 0.11 mM

The value of the (F-e-S-C-N⁺²) = 0.11 m-M when the student made additional dilutions.

Calculation of the value of the (F-e-S-C-N⁺²):

Since

M (F-e(N-O₃)₃  = 0.200 M

V (F-e(N-O₃)₃ =  10.63 mL

n (F-e(N-O₃)₃ = 0.200*10.63

= 2.126 mmol

M (K-S-C-N) =  0.00200 M

V (K-S-C-N) = 1.42 mL

And,

n (KS-C-N) =  0.00200 * 1.42 = 0.00284 mmol

Now

Total volume = V (F-e(N-O₃)₃  + V (K-S-C-N)

                      = 10.63 + 1.42

                      = 12.05 mL

Also, Limiting reactant = K-S-C-N

So,

F-e-S-C-N⁺² = 0.00284 mmol

M (F-e-S-C-N⁺²) = 0.00284/12.05

                    = 0.000236 M

Now

Excess reactant = (F-e(N-O₃)₃

n(F-e(N-O₃)₃ =  2.126 mmol -  0.00284 mmol

                 =2.123 mmol

Now For standard 2:

n (F-e-S-C-N⁺²) = 0.000236 * 4.63

                   =0.00109

V(standard 2) = 4.63 + 5.17

                      = 9.8 mL

M (F-e-S-C-N⁺²)  = 0.00109/9.8

                     = 0.000111 M = 0.11 mM

Therefore, (F-e-S-C-N⁺²) = 0.11 mM

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If the pH is 10 what is the concentration of hydroxide ion

Answers

Answer:

[OH-] = 10^-4 M

Explanation:

pOH= 14- pH= 14-10=4

[OH-]= antilog (-4)= 10^-4M

WHAT MASS OF WATER WILL BE PRODUCED FROM 2.70 MOLES OF CA(OH)2 REACTING WITH HCI

Answers

Answer: The mass of water produced in the reaction is 97.2 grams

Explanation:

We are given:

Moles of calcium hydroxide = 2.70 moles

The chemical equation for the reaction of calcium hydroxide and HCl follows:

[tex]Ca(OH)_2+HCl\rightarrow CaCl_2+2H_2O[/tex]

By Stoichiometry of the reaction:

1 mole of calcium hydroxide produces 2 moles of water

So, 2.70 moles of calcium hydroxide will produce = [tex]\frac{2}{1}\times 2.70=5.40mol[/tex] of HCl

To calculate mass for given number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Molar mass of water = 18 g/mol

Moles of water = 5.40 moles

Putting values in above equation, we get:

[tex]5.40mol=\frac{\text{Mass of water}}{18g/mol}\\\\\text{Mass of water}=(5.40mol\times 18g/mol)=97.2g[/tex]

Hence, the mass of water produced in the reaction is 97.2 grams

The correct answer is 54.0 grams of water will be produced from 2.70 moles of Ca(OH)2 reacting with HCl.

 To solve this problem, we need to consider the stoichiometry of the reaction between calcium hydroxide (Ca(OH)2) and hydrochloric acid (HCl). The balanced chemical equation for this reaction is:

[tex]Ca(OH)_2(s) + 2HCl(aq) \rightarrow CaCl_2(aq) + 2H_2O(l)[/tex]

 From the equation, we can see that 1 mole of Ca(OH)2 produces 2 moles of H2O upon reacting with excess HCl.

 Given that we have 2.70 moles of Ca(OH)2, we can calculate the moles of water produced using the stoichiometric ratio:

[tex]2.70 \ moles \ Ca(OH)_2 \times (2 \ moles \ H_2O / 1 \ mole \ Ca(OH)_2) = 5.40 \ moles \ H_2O[/tex]

 Now, we need to convert the moles of water to grams using the molar mass of water (H2O), which is approximately 18.015 grams per mole:

[tex]5.40 \ moles \ H_2O \times (18.015 \ grams \ H_2O / 1 \ mole \ H_2O) = 97.281 \ grams \ H_2O[/tex]

 However, this calculation is incorrect because it does not take into account the correct stoichiometry of the reaction. The balanced equation shows that 1 mole of Ca(OH)2 produces 2 moles of H2O, not 1 mole. Therefore, the correct calculation should be:

[tex]2.70 \ moles \ Ca(OH)_2 \times (2 \ moles \ H_2O / 1 \ mole \ Ca(OH)_2) \times (18.015 \ grams \ H_2O / 1 \ mole \ H_2O) = 54.0 \ grams \ H_2O[/tex]

 Thus, the mass of water produced from 2.70 moles of Ca(OH)2 reacting with HCl is 54.0 grams.

Consider two equal-volume balloons under the same conditions of temperature and pressure. One contains helium, and the other contains carbon dioxide.

Which of the following are the SAME for these two gas samples. Select all choices that apply.

Number of gas particles (atoms or molecules)

Density

Number of moles of gas

Average kinetic energy

Average particle velocity

Mass

Answers

Answer:

1. Number of gas particles (atoms or molecules)

2. Number of moles of gas

3. Average kinetic energy

Explanation:

Since the two gas has the same volume and are under the same conditions of temperature and pressure,

Then:

1. They have the same number of mole because 1 mole of any gas at stp occupies 22.4L. Now both gas will occupy the same volume because they have the same number of mole

2. Since they have the same number of mole, then they both contain the same number of molecules as explained by Avogadro's hypothesis which states that at the same temperature and pressure, 1 mole of any substance contains 6.02x10^23 molecules or atoms.

3. Being under the same conditions of temperature and pressure, they both have the same average kinetic energy. The kinetic energy of gas is directly proportional to the temperature. Now that both gas are under same temperature, their average kinetic energy are the same.

The answer choices which are the SAME for these two gas samples are

1. Number of gas particles (atoms or molecules)2. Number of moles of gas3. Average kinetic energyWhat is Kinetic Energy?

This refers to the type  of energy which has to do with the motion of an object.

Hence, we can see that since the two gas has the same volume and are under the same conditions of temperature and pressure,

We would infer that:

They have the same number of moles They have the same number of molecules based on Avogadro's number.They have the same average kinetic energy because of the similar conditions of temperature and pressure

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The reaction you actually perform in this experiment has some complexity in the mechanism (Solomons p904), but you can analyze a more simple two step version. Draw the arrow-pushing mechanism of the first step of this mechanism to form an imine. b) Draw the arrow-pushing mechanism of the second step of this mechanism to convert the imine to an amine using sodium borohydride.

Answers

Answer:

Explanation:

Attach is the solution

Final answer:

The formation of an imine involves nucleophilic addition, carbinolamine formation, and subsequent deprotonations leading to the imine, which is then reduced to an amine by sodium borohydride through nucleophilic attack.

Explanation:

Arrow-pushing Mechanism for Imine and Amine Formation

The question involves describing the arrow-pushing mechanisms for the formation of an imine from an aldehyde and ammonia, followed by the conversion of the imine to an amine using sodium borohydride. Let's address this step by step.

Step 1: Formation of Imine

The formation of an imine involves several key steps:

Nucleophilic addition of the amine to the carbonyl carbon of the aldehyde.Formation of carbinolamine via proton transfer.Protonation of carbinolamine oxygen turns it into a better leaving group, facilitating its elimination as water and resulting in the formation of an iminium ion.Finally, deprotonation of the nitrogen atom yields the imine.

Step 2: Conversion of Imine to Amine

In the next step, sodium borohydride (NaBH4) is used as a reducing agent to convert the imine into an amine. This involves the nucleophilic attack of hydride (H:-) from NaBH4 on the carbon atom of the iminium ion, leading to the formation of an amine.

A reaction was performed in which 3.4 g of benzoic acid was reacted with excess methanol to make 1.2 g of methyl benzoate. Calculate the theoretical yield and percent yield for this reaction.

Answers

Answer : The theoretical yield and percent yield for this reaction is, 3.78 grams and 31.7 % respectively.

Explanation : Given,

Mass of [tex]C_6H_5COOH[/tex] = 3.4 g

Molar mass of [tex]C_6H_5COOH[/tex] = 122.12 g/mol

First we have to calculate the moles of [tex]C_6H_5COOH[/tex]

[tex]\text{Moles of }C_6H_5COOH=\frac{\text{Given mass }C_6H_5COOH}{\text{Molar mass }C_6H_5COOH}[/tex]

[tex]\text{Moles of }C_6H_5COOH=\frac{3.4g}{122.12g/mol}=0.0278mol[/tex]

Now we have to calculate the moles of [tex]C_6H_5COOCH_3[/tex]

The balanced chemical equation is:

[tex]C_6H_5COOH+CH_3OH\rightarrow C_6H_5COOCH_3[/tex]

From the reaction, we conclude that

As, 1 mole of [tex]C_6H_5COOH[/tex] react to give 1 mole of [tex]C_6H_5COOCH_3[/tex]

So, 0.0278 mole of [tex]C_6H_5COOH[/tex] react to give 0.0278 mole of [tex]C_6H_5COOCH_3[/tex]

Now we have to calculate the mass of [tex]C_6H_5COOCH_3[/tex]

[tex]\text{ Mass of }C_6H_5COOCH_3=\text{ Moles of }C_6H_5COOCH_3\times \text{ Molar mass of }C_6H_5COOCH_3[/tex]

Molar mass of  = 136.14 g/mole

[tex]\text{ Mass of }C_6H_5COOCH_3=(0.0278moles)\times (136.14g/mole)=3.78g[/tex]

The theoretical yield of [tex]C_6H_5COOCH_3[/tex] produced is, 3.78 grams.

Now we have to calculate the percent yield of the reaction.

Theoretical yield of the reaction = 3.78 g

Experimental yield of the reaction = 1.2 g

The formula used for the percent yield will be :

[tex]\text{Percent yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100[/tex]

Now put all the given values in this formula, we get:

[tex]\text{Percent yield}=\frac{1.2g}{3.78g}\times 100=31.7\%[/tex]

The percent yield of the reaction is, 31.7 %

Which of the following series of scientific steps is most likely in the correct order?

Question 6 options:

observation, theory, experiment

scientific law, experiment, theory

observation, hypothesis, experiment

hypothesis, theory, experiment

Answers

Observation, hypothesis, experiment is the correct answer

Answer:

C

Explanation: you have to observe to have an educated guess about something you test it

Metal can not conduct electricity True or False?

Answers

Answer:

False

Explanation:

Metals are made up of atoms bonded to each other by metallic bonds. Such bonds have a sea of delocalized electrons, which are free to flow. Electricity requires an unobstructed flow of electrons in order to be able to be conducted. Because all metals provide this inherently, then all metals can conduct electricity, making the statement false.

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In the PhET simulation window, click the Macro menu in the top left corner of the screen. This view gives a view of the beaker at a macroscopic level (as your naked eye would see it). The Micro menu shows what happens to sugars and salts at the molecular level when they dissolve in water (note that you can use the arrows to switch to other type of solutes). Use both the Macro and Micro menus in the PhET simulation to help complete the following statements regarding solutions.

Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

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ions

solute

negatively

opposite

Partical Charges

positively

NaCl

sugar

CaCl2

1. Pure water contains only water molecules that interact strongly with each other due to their ___________, which are graphically depicted as δ+ and δ−.

2. Solutions are formed when a _______ like a salt or sugar becomes homogeneously distributed in a solvent like water, and this distribution can be viewed in the Micro view.

3. When salts dissolve, they separate into individua________that strongly interact with the water molecules.

4. Binary salts are made up of two elements at varying ratios, where one element is a charged cation, and the other is a_________ charged anion.

5. In the Micro view, each shake of the container releases 6 molecules of its respective solute, but 6 molecules of the salt________actually produce more ions in solution than 6 molecules of the salt__________.

6. Not all soluble molecules are salts, e.g., a covalent species like__________readily dissolves in water without forming ions.

7. The reason they dissolve is because their partially charged atoms are able to associate with the partially charged atoms of water molecules, and these attractive forces occur as long as they are between atoms with_________charges.

Answers

Final answer:

This question is about the Macro and Micro views of the PhET simulation for solutions and the concepts related to dissolving salts and sugars in water.

Explanation:

1. Pure water contains only water molecules that interact strongly with each other due to their partial charges, which are graphically depicted as δ+ and δ−.

2. Solutions are formed when a solute like a salt or sugar becomes homogeneously distributed in a solvent like water, and this distribution can be viewed in the Micro view.

3. When salts dissolve, they separate into individual ions that strongly interact with the water molecules.

4. Binary salts are made up of two elements at varying ratios, where one element is a charged cation, and the other is a negatively charged anion.

5. In the Micro view, each shake of the container releases 6 molecules of its respective solute, but 6 molecules of the salt NaCl actually produce more ions in solution than 6 molecules of the salt CaCl2.

6. Not all soluble molecules are salts, e.g., a covalent species like sugar readily dissolves in water without forming ions.

7. The reason they dissolve is because their partially charged atoms are able to associate with the partially charged atoms of water molecules, and these attractive forces occur as long as they are between atoms with opposite charges.

Learn more about Solutions and Dissolving here:

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Final answer:

This answer explains the properties of solutions, including partial charges and the formation of ions. It also provides examples of different solutes and their behavior in water.

Explanation:

1. Pure water contains only water molecules that interact strongly with each other due to their partial charges, which are graphically depicted as δ+ and δ−.

2. Solutions are formed when a solute like a salt or sugar becomes homogeneously distributed in a solvent like water, and this distribution can be viewed in the Micro view.

3. When salts dissolve, they separate into individual ions that strongly interact with the water molecules.

4. Binary salts are made up of two elements at varying ratios, where one element is a charged cation, and the other is a negatively charged anion.

5. In the Micro view, each shake of the container releases 6 molecules of its respective solute, but 6 molecules of the salt NaCl actually produce more ions in solution than 6 molecules of the salt sugar.

6. Not all soluble molecules are salts, e.g., a covalent species like sugar readily dissolves in water without forming ions.

7. The reason they dissolve is because their partially charged atoms are able to associate with the partially charged atoms of water molecules, and these attractive forces occur as long as they are between atoms with opposite charges.

Learn more about Solutions here:

https://brainly.com/question/30665317

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A person can burn 550 Calories by running at a moderate pace for one hour. Calculate the number of Calories that would be burned if the person only ran for 22 minutes. (1 hr = 60 min) Write only the number (answer) with 3 sig. fig.

Answers

Answer:

calories burned = 202 calories

Explanation:

22 minutes = 22/60th of an hour => calories burned in 22 min = (22/60)550 calories = 202 calories.

Answer:

202 calories is the estimate of calories burned

Explanation:

22 minutes = 22/60th of an hour => calories burned in 22 min = (22/60)550 calories = 202 calories.

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