A student obtained a clean flask. She weighed the flask and stopper on an analytical balance and found the total mass to be 34.232 g. She then filled the flask with water and found the new mass to be 60.167 g. The temperature of the water was measured to be

Explanation:

Heat of hydrogenation of alkenes is a measure of the stability of carbon-carbon double bonds.

In general, the lower the value of the heat of hydrogenation the more stable the double bond of the alkene.

Also, heat of hydrogenation of alkenes always have a negative value.

Answer:

Partial pressure (Ar) = 316.1mmHg

Explanation:

In the mixture of Ar and H₂ you can find the total moles of both gases using general gas law and with the mass of the sample and molar weight of each gas find the mole fraction of Argon and thus, its partial pressure.

Moles of gases:

PV = nRT

P = 910.0mmHg ₓ (1atm / 760mmHg) = 1.1974atm

V = 1.66L

n = Moles gases

R = 0.082atmL/molK

T = 54.9°C + 273.15K = 328.05K

PV = nRT

1.1974atm*1.66L = n*0.082atmL/molK*328.05K

Knowing H₂ = 2.016g/mol and Ar = 39.948g/mol you can write:

1.13g = 2.016X + 39.948Y (1)

Where X = moles of hydrogen and Y = moles of Argon.

Also we can write:

0.0739moles = X + Y (2)

Total moles of the sample are moles of hydrogen + moles Argon

Replacing 2 in 1:

1.13g = 2.016(0.0739-Y) + 39.948Y

1.13 = 0.1564 - 2.016Y + 39.948Y

0.9736 = 37.932Y

0.02567 = Y = moles of Argon

As total moles are 0.0739moles, mole fraction of Ar in the sample are:

XAr = 0.02567mol / 0.0739mol

X Ar = 0.347

Last, partial pressure of Ar = X Ar * total pressure.

Partial pressure (Ar) = 0.347*910.0mmHg

Answer:

2 AgNO3 + Na2SO4 → Ag2SO4 + 2 NaNO3

Explanation:

The general schemefor a reaction is given as;

Reactants --> Products

In this question, the reactants are AgNO3 and Na2SO4. The product is Ag2SO4.

The equation is given as;

AgNO3 + Na2SO4 --> Ag2SO4

The other poduct formed in this reaction is NaNO3.

The full reaction is given as;

AgNO3 + Na2SO4 --> Ag2SO4 + NaNO3

The above reaction is not balanced because there are unequal number of atoms of the elements on both sides of the reaction.

The balanced equation is given as;

2 AgNO3 + Na2SO4 → Ag2SO4 + 2 NaNO3

In this equation, there are equal number of moles of the atoms on both sides.

Answer:

The half life of the radio - active isotope is 8 hours

Explanation:

We can tell that half - life of this radio - active isotope will be the time span with which 100 cpm of the substance remains, as half of 100 cpm is 200 cpm. When 25 cm remains it takes the duration of 24 hours / 1 day.

25 cm / 200 cm = 1 / 8

Therefore 1 / 8 of the substance remains after 24 hours. We want to calculate the time it takes for 1 / 2 of the substance to remains, which should clearly be less than 24 hours,

1 / 2 [tex]*[/tex] 1 / 2

24 / 3 = 8 hours - three half lives fit into 1 / 8, and hence 24 / 3 = 8 hours. We can check this solution by considering this 8 hours. After 8 hours one - half of the substance remains, or 100 cpm. After another 8 hours one - half of 100 cpm remains, or 50 cpm. And after another 8 hours one - half of 50 cpm remains, or 25 cpm. 3, 8 hours is a duration of 24 hours - the remaining amount being 25 cpm.

Answer:

0.0590 M⁻¹

Explanation:

Kc represents the equilibrium constant. It is given as;

Kc = [products] / [reactants]

For the reaction; 2SO2(g) + O2(g) <--> 2SO3

Products = SO3

Reactants = SO2 and O2

Kc is given as;

Kc = [SO3]² / [SO2]² [O2]

Kc = 0.120² / (0.860)² (0.330)

Kc = 0.0144 / 0.2440 = 0.0590 M⁻¹

Answer:

Percentage mass of Tin = 96.3%

Percentage mass of oxygen = 6.40%

Explanation:

The product of the reaction is an oxide of tin.

Assuming all of the 0.500 g sample of tin reacted with oxygen to produce the oxide:

Mass of oxide = 0.534 g

Mass of tin present in the oxide = 0.500 g

Mass of oxygen in the oxide = 0.534 g of oxide - 0.500 g Sn = 0.034 g O

Percentage composition = mass of element/mass of compound × 100%

Percentage composition of Sn = 0.500 g/0.534 g × 100 = 93.6% Sn

Percentage composition of oxygen = 0.034 g/0.534 g × 100 = 6.40%

Answer:

1. 0.138g of valium would be lethel in the woman

2. 125mg/min is the drip of the patient

Explanation:

1. In a body, an amount of Valium > 1.52mg / kg of body weight would be lethal.

A person that weighs 200lb requires:

200lb × (453.6g / 1lb) × (1kg / 1000g) = 90.72kg (Weight of the woman in kg)

90.72kg × (1.52mg / kg) =

137.9mg ≡

2. The IV contains 1.5g = 1500mg/mL.

If the patient is receiving 5.0mL/h, its rate in mg/h is:

5.0mL/h × (1500mg/mL) = 7500mg/h

Now as 1h = 60min:

7500mg/h × (1h / 60min) =

Answer:

C. rate = k[F₂] [Cl₂O]

Explanation:

Based on the reaction, rate law can be obtained from the initial concentration of reactants thus:

rate = k[F₂]ᵃ [Cl₂O]ᵇ

Where the exponents a and b can be finded doing a experiment changing initial concentrations and seeing how a variation contribute in rate law.

If you analize experiments 1 and 2, the only change is [Cl₂O] (From 0.010 to 0.040, four times more) that changes its concentration in four times. This change produce rate law change from 5x10⁻⁴ to 2.0x10⁻³, also four times. That means the exponent b of [Cl₂O] is 1.

rate = k[F₂]ᵃ [Cl₂O]ᵇ

rate = k[F₂]ᵃ [Cl₂O]¹

Now, comparing experiments 1 and 3, the [F₂] change from 0.05 to 0.10, (Twice), and initial rate change from 5x10⁻⁴ to 1x10⁻³ (Also, twice). That means a = 1 and rate law is:

rate = k[F₂]¹ [Cl₂O]

rate = k[F₂] [Cl₂O]

Thus, right answer is:

Answer:

[tex]m_{Ti}=13.0g[/tex]

Explanation:

Hello,

In this case, based on the given, we can infer that as titanium is hot and water cold, it cools down whereas the water is heated up, therefore, in terms of heat, we have that the heat lost by the titanium is gained by the water:

[tex]-Q_{Ti}=Q_{H_2O}[/tex]

That in terms of mass, specific heat and temperatures is:

[tex]-m_{Ti}Cp_{Ti}(T_2-T_{Ti})=m_{H_2O}Cp_{H_2O}(T_2-T_{H_2O})[/tex]

In such a way, for computing the mass of titanium, considering the heat capacity of water 4.18 J/g°C, we have:

[tex]m_{Ti}=\frac{m_{H_2O}Cp_{H_2O}(T_2-T_{H_2O})}{-Cp_{Ti}(T_2-T_{Ti})} \\\\m_{Ti}=\frac{50.0g*4.18\frac{J}{g\°C}(22.6-20.0)\°C}{-0.54\frac{J}{g\°C}*(22.6-100.0)\°C} \\\\m_{Ti}=13.0g[/tex]

Regards.

Answer:

2-ethoxy-2-methylpropan-1-ol

Explanation:

On this reaction, we have an "epoxide" (2-methyl-1,2-epoxypropane). Additionally, we have acid medium (due to the sulfuric acid [tex]H_2SO_4[/tex]). The acid medium will produce the hydronium ion ([tex]H^+[/tex]). This ion would be attacked by the oxygen of the epoxide. Then a carbocation would be produced, in this case, the most stable carbocation is the tertiary one. Then an ethanol molecule acts as a nucleophile and will attack the carbocation. Finally, a deprotonation step takes place to produce 2-ethoxy-2-methylpropan-1-ol.

See figure 1

I hope it helps!

Answer:

work is done on the system by the surroundings

Explanation:

An endothermic process is any process in which energy is absorbed by the system from the surrounding, usually in the form of heat energy. Energy intake is usually associated with bond braking, and the energy from the surrounding goes into breaking the chemical bond between atoms int the reaction. The quantity of heat absorbed in any endothermic process can be calculated for by analyzing the Gibbs free energy of the reaction system. Endothermic process is mostly associated with heat energy intake by the system from the surrounding, but can also be used to refer to any system that undergoes any form of energy input into the system, from the surrounding even in the form of work.

Answer:

1. b.) The wavelength gets shorter as the frequency increases  

2. X-rays < Ultraviolet radiation < Visible light < Infrared radiation

3. 2 × 10⁵ J

Explanation:

1. Wavelength vs frequency

fλ= c

f = c/λ

Thus, frequency and wavelength are inversely proportional.

The wavelength increases (gets longer) as the frequency decreases.

2. Order of increasing wavelength

X-rays < Ultraviolet radiation < Visible light < Infrared radiation  

3. Energy of green light

(a) Energy of 1 photon

λ = 5 × 10² nm = 5  × 10² × 10⁻⁹ m = 5 × 10⁻⁷ m

fλ = c

f = c/λ = (2.998 × 10⁸ m·s⁻¹)/(5 × 10⁻⁷ m) = 6 × 10¹⁴ s⁻¹

E = hf = 6.626 × 10⁻³⁴ J·s × 6 × 10¹⁴ s⁻¹ = 4 × 10⁻¹⁹ J

(b) Energy  of 1.0 mol of photons

[tex]\text{Energy} = \text{1.0 mol photons} \times \dfrac{6.022 \times 10^{23}\text{ photons }}{\text{1 mol photons }} \times \dfrac{4 \times 10^{-19}\text{ J}}{\text{1 photon }} = \mathbf{2 \times 10^{5}} \textbf{ J}\\\\\text{The energy of 1.0 mol of photons of green light is $\large \boxed{\mathbf{2 \times 10^{5}}\textbf{ J}}$}[/tex]

Note: The answer can have only one significant figure because that is all you gave for the wavelength of the light.

Answer:

I think the answer is " Night vision glasses detect Infrared" energy emitted from cooling objects.

Explanation:

Answer: one by one

Explanation:

The given question is incomplete. The complete question is :

A chemist prepares a solution of barium acetate by measuring out 32 g of barium acetate into a 350 ml volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's barium acetate solution. Round your answer to significant digits.

Answer:  The concentration of barium acetate solution is 0.375 mol/L

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in ml

moles of [tex]Ba(CH_3COO)_2[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{32g}{255g/mol}=0.125mol[/tex]

Now put all the given values in the formula of molality, we get

[tex]Molarity=\frac{0.125\times 1000}{350ml}[/tex]

[tex]Molarity=0.357M[/tex]

Therefore, the concentration of solution is 0.375 mol/L

Answer:

C

Explanation:

Turning liquid to a solid is like freezing water to ice and requires the water to LOSE (release) heat causing an exothermic reaction.

Answer:

Do not conduct electricity as solids.

Explanation:

Hello,

In this case, we should remember that salts are formed when an acid and base react in order to yield the salt and water due to the ions exchange during neutralization chemical reactions. For instance, when hydrochloric acid  (acid) reacts with potassium hydroxide (base), sodium chloride (salt) and water are yielded via:

[tex]HCl+NaOH\rightarrow NaCl+H_2O[/tex]

Moreover, it is widely known that salts are formed by electrovalent/ionic bonds which involves electron transfer so the metallic atom becomes positively charged (cation) whereas the non-metallic atom becomes negatively charged (anion) once the electrons are received so it can conduct electricity when dissolved in water yet not when solid since electron transfer is facilitated by the aqueous media, otherwise, ions remain together. Thereby, answer is do not conduct electricity as solids.

Regards.

Answer:

c

Explanation:

Answer:

Lewis acid- Fe3+

Lewis base- water molecule

Explanation:

Acids and bases have been defined in diverse ways. There have been definitions put forward by Arrhenius, Brownstead and Lowry as well as Lewis. Each definition his useful in its own way.

Lewis acids are lone pair acceptors such as metal ions. This implies that in the particular instance of this reaction, Fe3+ is the lewis acid.

Similarly, a Lewis base is a lone pair donor, all ligands are lone pair donors since they donate one or more lone pairs of electrons to Lewis acids. In the particular instance of this reaction, the Lewis base is the water molecule.

The branch of science which deals with the chemicals bond is called chemistry.

The correct answer is Lewis acid [tex]Fe^{3+[/tex]  and the lewis base is a water molecule.

Those chemicals which release the H+ ion when reacting with water are called acids. Those chemicals which release OH- ion, when reacted with the water is called a base. These definitions are given by the Lewis

Lewis acids are lone pair acceptors such as metal ions. This implies that in the particular instance of this reaction, Fe3+ is the lewis acid.

Similarly, a Lewis base is a lone pair donor, all ligands are lone pair donors since they donate one or more lone pairs of electrons to Lewis acids. In the particular instance of this reaction, the Lewis base is the water molecule.

Hence, the correct answer is Fe3+.

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The molecular equation is :[tex]HI(aq)+KOH(aq) -- > KI (aq) + H_2O (l)[/tex]

The net ionic equation is: [tex]H^+(aq) + OH^-(aq) -- > H_2O(l)[/tex]

When hydroiodic acid reacts with potassium hydroxide, this will result in the formation of a salt i.e. potassium iodide, and water is obtained as a by-product.

The molecular equation can be represented as:

[tex]HI(aq)+KOH(aq) -- > KI (aq) + H_2O (l)[/tex]

The net-ionic equation can be represented as:

[tex]H^+(aq) + OH^-(aq) -- > H_2O(l)[/tex]

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A molecular equation is a balanced chemical equation that represents a chemical reaction by showing the complete chemical formulas of all reactants and products involved. The net ionic equation for the reaction is as follows:

[tex]H+(aq) + OH-(aq) = H_2O(l)[/tex]

The molecular equation for the reaction between hydroiodic acid (HI) and potassium hydroxide (KOH) can be written as follows:

[tex]HI(aq) + KOH(aq) = KI(aq) + H_2O(l)[/tex]

In this equation, (aq) represents aqueous solutions, indicating that the substances are dissolved in water, and (l) represents a liquid phase for water.

To write the net ionic equation, we need to remove the spectator ions that do not participate in the actual chemical reaction. In this case, potassium ion (K+) and iodide ion (I-) are spectator ions, meaning they appear on both sides of the equation without undergoing any change.

Therefore, the net ionic equation for the reaction is as follows:

[tex]H+(aq) + OH-(aq) = H_2O(l)[/tex]

In the net ionic equation, H+ represents the hydrogen ion from hydroiodic acid, and OH- represents the hydroxide ion from potassium hydroxide. These ions combine to form water ([tex]H_2O[/tex]) as the only product.

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Answer:

Water (H2O) is an inorganic chemical compound formed by two hydrogen (H) and one oxygen (O) atoms. 3 This molecule is essential in the life of living beings, serving as a medium for the metabolism of biomolecules, is found in nature in its three states and was key to its formation. It is necessary to distinguish between drinking water and pure water, since the first is a mixture that also contains salts in solution; this is why in the laboratory and in other areas distilled water is used.

Explanation:

I hope I've helped

According to the molecular geometry, the V-shape or bent structure best describes the shape of water molecule.

Molecular geometry can be defined as a three -dimensional arrangement of atoms which constitute the molecule.It includes parameters like bond length,bond angle and torsional angles.

It influences many properties of molecules like reactivity,polarity color,magnetism .The molecular geometry can be determined by various spectroscopic methods and diffraction methods , some of which are infrared,microwave and Raman spectroscopy.

They provide information about geometry by taking into considerations the vibrational and rotational absorbance of a substance.Neutron and electron diffraction techniques provide information about the distance between nuclei and electron density.

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Answer

mass of aluminum metal= 7 .0497g of Al

Explanation:

current = 21 A

time = 1 hour = 60 X 60 = 3600 s

quantity of electricity passed = current X time = 21X 3600 = 75600 C

Following the electrolysis the below reaction will occur :

Al3+ + 3e- --------> Al

therefore, 3F i.e. 3 X 96500 C = 289500 C gives 1 mole of Al

so 1 C will produce 1/289500 moles of Al

so 108000 C will produce 1/289500 X 75600 = 0.2611 moles of Al

now 1 mole of aluminium weighs = 27 g/mole

so 0.2611 moles of Al = 0.2611 X 27 = 7 .0497 g

mass of aluminum metal= 7 .0497 g of Al

The mass of aluminum metal can be produced per hour in the electrolysis of a molten aluminum salt by a current of 21 A is 7.05 g

We'll begin by calculating the the quantity of electricity used. This can be obtained as follow:

Current (I) = 21 A

Time(t) = 1 h = 60 × 60 = 3600 s

Q = it

Q = 21 × 3600

Recall:

1 mole of Al = 27 g

1 electron (e) = 96500 C

Thus,

3 electrons = 3 × 96500 = 289500 C

From the balanced equation above,

289500 C of electricity produced 27 g of Al.

Therefore,

75600 C of electricity will produce = (75600 × 27) / 289500 = 7.05 g of Al

Thus, the mass of the aluminum metal obtained is 7.05 g

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Answer:

See explanation below

Explanation:

Carbon has four electrons in its outermost shell. The CO3^2- anion is found to be in the trigonal planar geometry. For a carbon atom in the trigonal planar geometry, the carbon is sp2 hybridized. This implies that an s orbital mixes with two p orbitals to yield the hybrid orbitals in the ion.

Carbon forms three double bonds to three oxygen atoms using these hybrid sp2 orbitals. Recall that the actual bonding in each C-O linkage lies between that of a pure C-O single bond and C-O double bonds.

Note that there are two p orbitals and one s orbital participating in this hybridization hence three hybrid orbitals are expected to be formed.

The given question is incomplete, the complete question is:

A chemistry student weighs out 0.0349g of formic acid HCHO2 into a 250.mL volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.1500M NaOH solution. Calculate the volume of NaOH solution the student will need to add to reach the equivalence point. Round your answer to 3 significant digits.

Answer:

The correct answer is 5.06 ml.

Explanation:

Based on the given information, the weight of formic acid given is 0.0349 grams. The volume of formic acid of V1 given is 250 ml. The molecular mass of formic acid is 46 grams per mole. Now the molarity of formic acid will be,  

[HCOOH] = weight * 1000 / molecular mass * volume (ml)

= 0.0349 * 1000 / 46 * 250

= 0.003035 M or M1

The molarity of NaOH given is 0.1500 M or M2

Let us assume that the volume needed to attain equivalence point is V2 ml.  The volume V2 can be determined by using the dilution equation,  

M1V1 = M2V2

V2 = M1V1/M2  

V2 = 0.003035 * 250 / 0.1500

V2 = 5.06 ml.  

Hence, the volume of NaOH needed is 5.06 ml.  

Answer:

[tex]Kp=0.0386[/tex]

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

[tex]2NO+O_2\rightleftharpoons 2NO_2[/tex]

For which the equilibrium expression is:

[tex]Kp=\frac{p_{NO_2}^2}{p_{NO}^2p_{O_2}}[/tex]

Whereas, at equilibrium, each pressure is computed in terms of the initial pressure and the reaction extent via:

[tex]p_{NO_2}=2x\\p_{NO}=522-2x\\p_{O_2}=421-x[/tex]

And the total pressure:

[tex]p_{eq}=p_{NO_2}+p_{NO}+p_{O_2}\\\\p_{eq}=2x+522-2x+421-x\\\\p_{eq}=943-x[/tex]

Yet it is 748 torr, for which the extent is:

[tex]x=943-p_{eq}=943-748\\\\x=195torr[/tex]

Therefore, Kp turns out:

[tex]Kp=\frac{(2x)^2}{(522-2x)^2(421-x)}\\\\Kp=\frac{(2*195)^2}{(522-2*195)^2(421-195)}\\\\Kp=0.0386[/tex]

Best regards.

Answer:

reduces the greenhouse effect

Answer: 9.08 L

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}\times{\text{Molar Mass}}[/tex]    

[tex]\text{Moles of} Al=\frac{14.6g}{27g/mol}=0.54moles[/tex]

[tex]4Al+3O_2\rightarrow 2Al_2O_3[/tex]

According to stoichiometry :

4 moles of [tex]Al[/tex] require  = 3 moles of [tex]O_2[/tex]

Thus 0.54 moles of [tex]Al[/tex] will require=[tex]\frac{3}{4}\times 0.54=0.405moles[/tex]  of [tex]O_2[/tex]

Standard condition of temperature (STP)  is 273 K and atmospheric pressure is 1 atm respectively.

According to the ideal gas equation:

[tex]PV=nRT[/tex]

P = Pressure of the gas = 1 atm

V= Volume of the gas = ?

T= Temperature of the gas = 273 K      

R= Gas constant = 0.0821 atmL/K mol

n=  moles of gas= 0.405

[tex]V=\frac{nRT}{P}=\frac{0.405\times 0.0821\times 273}{1}=9.08L[/tex]

Thus 9.08 L of [tex]O_2[/tex] at STP would be required

Considering the reaction stoichiometry and STP conditions, 9.072 L of O₂ at STP would be required.  

The balanced reaction is:

4 Al + 3 O₂ → 2 Al₂O₃

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Being 27 g/mole the molar mass of Al, this is the amount of mass that a substance contains in one mole, then if 14.6 grams Al are reacted,   the number of moles of Al that react is calculated as:

[tex]14.6 gramsx\frac{1 mole}{27 grams}= 0.54 moles[/tex]

Then you can apply the following rule of three: if by stoichiometry 4 moles of Al react with 3 moles of O₂, 0.54 moles of Al react with how many moles of O₂?

[tex]amount of moles of O_{2} =\frac{0.54 moles of Alx3 moles of O_{2} }{4 moles of Al}[/tex]

amount of moles of O₂= 0.405 moles

On the other side, the STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

Then you can apply the following rule of three: if by definition of STP 1 mole of O₂ occupies 22.4 L, 0.405 moles of O₂, how much volume does it occupy?

[tex]volume=\frac{0.405 moles of O_{2}x22.4 L }{1 mole of O_{2} }[/tex]

volume= 9.072 L

Finally, 9.072 L of O₂ at STP would be required.  

Learn more:

Given that,

Draw the Lewis structure of acetaldehyde (CH₃CHO).

We know that,

The Lewis structure shows the number of electrons around an atom.

According to structure,

We need to find the molecular geometries of the two central atoms

Using molecular geometries

For first central atom,

Number of bond pair = 2

Here, double bond to O count as single bond

The number of lone pair is zero.

The geometry is Trigonal planar.

For second central atom,

Number of bond pair = 4

The number of lone pair is zero.

The geometry is tetrahedral

Hence, The molecular geometries of the two central atoms are trigonal planar and tetrahedral.

(d) is correct option.

The central carbon atoms in acetaldehyde have a tetrahedral geometry and a trigonal planar geometry respectively.

Acetaldehyde has two central carbon atoms. The Lewis structure of acetaldehyde shows the arrangement of electrons around the atoms in the compound. The lone pairs are shown as dots while the bond pairs are represented using a single dash.

The first central carbon atom in acetaldehyde has a tetrahedral geometry while the second central carbon atom in acetaldehyde has a trigonal planar geometry.

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Answer:

71.1

Explanation:

1 mol Fe = 10.4 g/55.85 g/mol = 0.186

1 mol AgNo3 = 28.4 g/169.87 g/mol = 0.178 mol AgNo3

then since Ag:Fe is 1:3, AgNo3 is the limiting reactant

So now

0.178 moles * 1/3 * 241.83 g/mol Fe(NO3)3 = 14.35 g Fe(NO3)3

Excess reactant: 0.178 moes AgNO3 * 1/3 = 0.059

0.186 - 0.059 = 0.127 moles Fe * 55.85 g/mol Fe = 7.1 g Fe excess

Answer:

pH = 4.79

Explanation:

The pH of the acetic buffer can be determined using H-H equation:

pH = pKa + log [A⁻] / [HA]

Where pKa is -logKa = 4.76

pH = 4.76 + log [sodium Acetate] / [Acetic Acid]

Where [] can be taken as moles of each specie.

Thus, to find pH of the buffer we need to calculate molesof acetic acid and sodium acetate.

Initial moles:

Initial moles of acetic acid and sodium acetate are:

500mL = 0.500L ₓ (0.60moles / L) = 0.30 moles of both acetic acid and sodium acetate

Moles after reaction:

Now, 0.010 moles of NaOH are added to the buffer reacting with acetic acid, CH₃COOH, producing more acetate ion, as follows:

NaOH + CH₃COOH → CH₃COO⁻ + H₂O

That means after reaction moles of both species are:

Acetic acid: 0.30mol - 0.010mol (Moles that react) = 0.29 moles

Acetate: 0.30mol + 0.010mol (Moles produced) = 0.31 moles

Replacing in H-H equation:

pH = 4.76 + log [0.31] / [0.29]