What is the molecular formula of the structure below?Picture is attached pls help I’ll mark as brainliest for the right answer

Answer:

The free energy = -20.46 KJ

Explanation:

given Data:

Pb²⁺ = 0.750 M

Br⁻ = 0.232 M

R = 8.314 Jk⁻¹mol⁻¹

T = 298K

The Gibb's free energy is calculated using the formula;

ΔG = ΔG° + RTlnQ -------------------------1

Where;

ΔG° = standard Gibb's freeenergy

R = Gas constant

Q = reaction quotient

T = temperature

The chemical reaction is given as;

Pb²⁺(aq) + 2Br⁻(aq) ⇄PbBr₂(s)

The ΔG°f are given as:

ΔG°f (PbBr₂)  = -260.75 kj.mol⁻¹

ΔG°f (Pb²⁺)   = -24.4 kj.mol⁻¹

ΔG°f (2Br⁻)    = -103.97 kj.mol⁻¹

Calculating the standard gibb's free energy using the formula;

ΔG° = ξnpΔG°(product) - ξnrΔG°(reactant)

Substituting, we have;

ΔG° =[1mol*ΔG°f (PbBr₂)] - [1 mol *ΔG°f (Pb²⁺) +2mol *ΔG°f (2Br⁻)]

ΔG° =(1 *-260.75 kj.mol⁻¹) - (1* -24.4 kj.mol⁻¹) +(2*-103.97 kj.mol⁻¹)

      = -260.75 + 232.34

     = -28.41 kj

Calculating the reaction quotient Q using the formula;

Q = 1/[Pb²⁺ *(Br⁻)²]

   = 1/(0.750 * 0.232²)

  = 24.77

Substituting all the calculated values into equation 1, we have

ΔG = ΔG° + RTlnQ

ΔG = -28.41 + (8.414*10⁻³ * 298 * In 24.77)

     = -28.41 +7.95

    = -20. 46 kJ

Therefore, the free energy of reaction = -20.46 kJ

Final answer:

To calculate the reaction free energy ΔG for this reaction, we need to use the standard free energy of formation values given in a data tab, the stoichiometry of the reaction, and the specific conditions of the reaction, including the concentrations of Pb2+ and Br−. After a series of calculations, we will get the ΔG value in joules, which can be converted to kilojoules.

Explanation:

The task here is to calculate the reaction free energy ΔG for the Pb2+(aq) + 2Br−(aq) = PbBr2(s) reaction at 25.0°C. From the given information, we can start by calculating the number of moles of PbBr2 from its mass. Then, referring to the thermodynamic data tab of the ALEKS, we find the standard free energy of formation (ΔGf°) values for Pb2+(aq), Br−(aq), and PbBr2(s). Now, we can use these values and the definition of ΔG for a reaction in terms of ΔGf° values and stoichiometry.

ΔG = ΣΔGf°(products) - ΣΔGf°(reactants).

Note that the equation must be balanced so each ΔGf° value is multiplied by the stoichiometric coefficient of that substance in the reaction. It is also important to remember to convert the answer to kilojoules if the ΔGf° values are given in joules/mole. Lastly, the concentrations of Pb2+ and Br− are included in the reaction quotient Q to show the reaction's non-standard conditions.

Learn more about Reaction Free Energy here:

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Answer:

pH = 7.1581

Explanation:

The equilibrium of NaHSO₃ with Na₂SO₃ is:

HSO₃⁻ ⇄ SO₃²⁻ + H⁺

Where K of equilibrium is the Ka2: 6.5x10⁻⁸

HSO₃⁺ reacts with NaOH, thus:

HSO₃⁻ + NaOH → SO₃²⁻ + H₂O + Na⁺

As the buffer is of 1.0L, initial moles of HSO₃⁻ and SO₃²⁻ are:

HSO₃⁻: 0.252 moles

SO₃²⁻: 0.139 moles

Based on the reaction of NaOH, moles added of NaOH are subtracting moles of HSO₃⁻ and producing SO₃²⁻. The moles added are:

0.0500L ₓ (1mol /L): 0.050 moles of NaOH.

Thus, final moles of both compounds are:

HSO₃⁻: 0.252 moles - 0.050 moles = 0.202 moles

SO₃²⁻: 0.139 moles + 0.050 moles = 0.189 moles

Using H-H equation for the HSO₃⁻ // SO₃²⁻ buffer:

pH = pka + log [SO₃²⁻] / [HSO₃⁻]

Where pKa is - log Ka = 7.187

Replacing:

pH = 7.187 + log [0.189] / [0.202]

pH = 7.1581

The statement about reaction A and reaction B are true is: A. Reaction B is likely to occur at a faster rate than reaction A.

An activation energy can be defined as the minimum quantity of energy that must be provided for reacting chemical elements, so as to undergo a chemical reaction. Thus, the activation energy of a chemical reaction must first of all be reached by its combining chemical elements (reactants) before it can start or begin.

As a general rule, the lower the activation energy of a chemical reaction, the faster is the rate of a chemical reaction and vice-versa. This ultimately implies that, the activation energy of a chemical reaction should be lowered, in order for it to occur fast (quickly) enough over a short period of time.

In conclusion, reaction B is likely to occur at a faster rate than reaction A because of its low activation energy.

Read more: brainly.com/question/537100

Answer:

The correct answer is:

Reaction B is more likely to occur at all than reaction A.

Explanation:

The activation energy in chemistry is the smallest amount of energy required to cause chemical or nuclear reaction in the reactants in chemical or nuclear systems. The activation energy is denoted by , and it is measured in Joules (J), KiloJoules (KJ) or Kilocalories per mole (Kcal/mol)

The activation energy can be thought of simply as the minimum amount of energy required to overcome a barrier that prevents a reaction from occurring, hence, from our question, if Reaction A has a high activation energy, it means that the barrier to be overcome before a reaction will occur is large, meaning that the reaction system is more stable and the reaction is less likely to occur than Reaction B which has a low activation energy, meaning that just a relatively small amount of energy, when applied to the reaction system, will initiate a reaction, making it more likely to occur than reaction A.

You should also note that catalysts are substances that are capable of reducing the activation energy of a system, but remains unchanged at the end of the system.

Answer: The pH of resulting solution is 10.893

Explanation:

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

• For ethylamine:

Molarity of ethylamine solution = 0.25 M

Volume of solution = 80 mL

Putting values in above equation, we get:

• For HCl:

Molarity of HCl = 0.100 M

Volume of solution = 20.0 mL

Putting values in above equation, we get:

• For :

Molarity of solution = 0.25 M

Volume of solution = 80 mL

Putting values in above equation, we get:

The chemical reaction for ethylamine and HCl follows the equation:

Initial:           0.02          0.002         0.02

Final:            0.018          -                0.022

Volume of solution = 20.0 + 80.0 = 100 mL = 0.100 L    (Conversion factor:  1 L = 1000 mL)

To calculate the pOH of basic buffer, we use the equation given by Henderson Hasselbalch:

We are given:

= negative logarithm of base dissociation constant of ethylamine =

pOH = ?

Putting values in above equation, we get:

To calculate pH of the solution, we use the equation:

Hence, the pH of the solution is 10.893

The pH of the solution is 10.9

Data;

• Volume of buffer = 80mL
• Volume of HCL = 20.0mL
• conc. of C2H5NH2 = 0.25M
• conc. of C2H5NH3Cl = 0.25
• Kb of C2H5NH2 = 9.5*10^-4

pH of a Solution

The pH of buffer can be calculated by using Henderson-Hasselbalch's equation

The initial moles of salt present is calculated as

The initial moles of base present is calculated as

On adding HCl the following reaction will occurs

This will lead to formation of extra moles of salt that is  equal to moles of acid added and eventually lead to decrease in number of moles of base by equal measure.

Moles of HCl added is

Adding the value

Moles of salt present = 20 + 2 = 22mmoles

Subtracting the value

Moles of base left = 20-2 = 18mmoles

Now using Henderson-Hasselbalch's equation we can calculate the pOH of solution

The pOH of the base can be calculated as

Using the above, we can solve for the pH of the solution.

The pH of the solution is 10.9

Learn more on pH of a solution using Henderson-Hasselbalch equation here;

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Answer:

              Structure is attached.

Explanation:

                    It is quite simple. The parent compound is benzaldehyde which is a benzene containing CHO functional group.

Now, starting numbering from CHO put methoxy (-OCH₃) groups at position 3 and 5.