Calculate the standard molar enthalpy of formation, in kJ/mol, of NO(g) from the following data:

N2 + 2NO2 = 2NO2 ΔH 66.4kJ @298k

2NO + 02 =2NO2 ΔH -114.1kJ @298k

Answer:

Mass = 12.82 g

Explanation:

Given data:

Mass of oxygen = 8.5 g

Mass of H₂S = 10.0 g

Mass of SO₂ = ?

Solution:

Chemical equation;

2H₂S + 3O₂ →  2SO₂ + 2H₂O

Number of moles of H₂S:

Number of moles = mass/ molar mass

Number of moles = 10.0 g / 34 g/mol

Number of moles =0.3 mol

Number of moles of oxygen:

Number of moles = mass/ molar mass

Number of moles = 8.5 g / 32 g/mol

Number of moles = 0.3 mol

Now we will compare the moles of SO2 with oxygen and hydrogen sulfide.

                         O₂             :         SO₂

                           3             :            2

                           0.3          :            2/3×0.3=0.2 mol

                         H₂S           :            SO₂

                           2              :            2

                         0.3             :           0.3

The number of moles of SO₂  produced by oxygen are less so it will limiting reactant.

Mass of SO₂:

Mass = number of moles × molar mass

Mass = 0.2 mol × 64.1 g/mol

Mass = 12.82 g

Answer:

7.43 × 10²⁴ m⁻³

Explanation:

Data provided in the question:

Conductivity of a semiconductor specimen, σ = 2.8 × 10⁴ (Ω-m)⁻¹

Electron concentration, n = 2.9 × 10²² m⁻³

Electron mobility, [tex]\mu_n[/tex] = 0.14 m²/V-s

Hole mobility, [tex]\mu_p[/tex]= 0.023 m²/V-s

Now,

σ = [tex] nq\mu_n+pq\mu_p[/tex]

or

σ = [tex] q(n\mu_n+p\mu_p)[/tex]

here,

q is the charge on electron = 1.6 × 10⁻¹⁹ C

p is the hole density

thus,

2.8 × 10⁴ = 1.6 × 10⁻¹⁹( 2.9 × 10²² × 0.14 +  p × 0.023 )

or

1.75 × 10²³ = 0.406 × 10²² + 0.023p

or

17.094 × 10²² = 0.023p

or

p = 743.217 ×  10²²

or

p = 7.43 × 10²⁴ m⁻³

A system that is giving off 65.0 kJ of heat and is performing 855 J of work on the surroundings has a change in the internal energy of -65.9 kJ.

According to the First Law of Thermodynamics, we can calculate the change in the internal energy (ΔE) of the system using the following expression.

[tex]\Delta E = Q + W = (-65.0 kJ) + (-0.855 kJ) = -65.9 kJ[/tex]

A system that is giving off 65.0 kJ of heat and is performing 855 J of work on the surroundings has a change in the internal energy of -65.9 kJ.

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Answer:

The minimum mass of acetaminophen that the new system must be able to detect is 0.02 milligrams.

Explanation:

Range of the equipment to detect acetaminophen in blood = 10.0  to 30.0 μg/mL

Minimum amount of acetaminophen that can be detected= 10.0 μg/mL

Volume of blood sample = 2 mL

Amount of acetaminophen in 2 ml sample of blood =

[tex]2 mL\times 10.0 \mu g/mL=20.0 \mu g[/tex]

20.0 μg = 0.02 mg (1 μg = 0.001 mg)

The minimum mass of acetaminophen that the new system must be able to detect is 0.02 milligrams.

Answer:

a)

[tex]C(s)+O_{2}(g) \rightarrow CO_{2}(g)[/tex]

[tex]S(s)+O_{2}(g) \rightarrow SO_{2}(g)[/tex]

b)

Sulphurdioxide

c)

[tex]SO_{2}(g) + H_{2}O(l) \rightarrow H_{2}SO_{3}(l)[/tex]

[tex]SO_{2}(g) + \frac{1}{2}O_{2} \rightarrow SO_{3}(g)[/tex]

d)  

Incomplete combustion produce harmful gases.

Explanation:

a)

Carbon reacts with atmospheric oxygen to form carbondioxide as well as sulphur dioxide.

The chemical equations are as follows.

[tex]C(s)+O_{2}(g) \rightarrow CO_{2}(g)[/tex]

[tex]S(s)+O_{2}(g) \rightarrow SO_{2}(g)[/tex]

b)

Sulfur dioxide is very harmful to the environment to cause acid rains.

This harmful gas mix with rain water to form  sulphuric acid.

c)

The balanced chemical equation for the reaction that produces harmful environmental effects is as follows.

[tex]SO_{2}(g) + H_{2}O(l) \rightarrow H_{2}SO_{3}(l)[/tex]

[tex]SO_{2}(g) + \frac{1}{2}O_{2} \rightarrow SO_{3}(g)[/tex]

[tex]SO_{3}(g) +H_{2}O(l) \rightarrow H_{2}SO_{4}(l)[/tex]

d)

In the absence of proper amount of oxygen required for combustion, incomplete combustion will take place which will result in formation of more carbondioxide an other harmful gases.

Answer:

119 kCal per serving.

Explanation:

The heat energy necessary to elevates water's temperature from 23.4°C to 37.9°C can be calculated by the equation below:

Q = mcΔT

Q: heat energy

m: mass in g

c: specific heat capacity in cal/g°C

ΔT = temperature variation in °C

m is the mass of water, considering the density of water to be 1g/mL, 100 mL of water weights  100g. Therefore:

Q = 100 g x 1.00 cal/g°C x (37.9 - 23.4)°C

Q = 1450 cal

1450 cal ____ 0.341 g peanuts

x             ____  28 g peanuts

x = 119061.58 cal

This means that the cal from fat per serving of peanuts is at least 119 kCal.

The temperature change of the water indicated 1.45 Calories for 0.341 grams of peanut. Therefore, a serving size of 28.0 grams contains option 2) 119 Calories from fat.

To determine the Calories from fat per serving, we must first calculate the energy released by the peanut during combustion and then scale it to a full serving size.

Thus, the Calories from fat per serving is option 2) 119 Cal/serving.

Answer:

Theoretical yield = 3.51 g

Explanation:

The formula for the calculation of moles is shown below:

[tex]moles = \frac{Mass\ taken}{Molar\ mass}[/tex]

For [tex]CH_4[/tex]  :-

Mass of [tex]CH_4[/tex]  = 1.28 g

Molar mass of [tex]CH_4[/tex]  = 16.04 g/mol

The formula for the calculation of moles is shown below:

[tex]moles = \frac{Mass\ taken}{Molar\ mass}[/tex]

Thus,

[tex]Moles= \frac{1.28\ g}{16.04\ g/mol}[/tex]

[tex]Moles_{CH_4}= 0.0798\ mol[/tex]

For [tex]O_2[/tex]  :-

Mass of [tex]O_2[/tex]  = 10.1 g

Molar mass of [tex]O_2[/tex]  = 31.998 g/mol

The formula for the calculation of moles is shown below:

[tex]moles = \frac{Mass\ taken}{Molar\ mass}[/tex]

Thus,

[tex]Moles= \frac{10.1\ g}{31.998\ g/mol}[/tex]

[tex]Moles_{O_2}= 0.3156\ mol[/tex]

According to the given reaction:

[tex]CH_4+2O_2\rightarrow CO_2+2H_2O[/tex]

1 mole of methane gas reacts with 2 moles of oxygen gas

0.0798 mole of methane gas reacts with 2*0.0798 moles of oxygen gas

Moles of oxygen gas = 0.1596 moles

Available moles of oxygen gas = 0.3156 moles

Limiting reagent is the one which is present in small amount. Thus, [tex]CH_4[/tex] is limiting reagent.

The formation of the product is governed by the limiting reagent. So,

1 mole of methane gas on reaction produces 1 mole of carbon dioxide.

0.0798 mole of methane gas on reaction produces 0.0798 mole of carbon dioxide.

Mole of carbon dioxide = 0.0798 mole

Molar mass of carbon dioxide = 44.01 g/mol

The formula for the calculation of moles is shown below:

[tex]moles = \frac{Mass\ taken}{Molar\ mass}[/tex]

Thus,

[tex]0.0798\ moles= \frac{Mass}{44.01\ g/mol}[/tex]

Mass of [tex]CO_2[/tex] = 3.51 g

Theoretical yield = 3.51 g

The theoretical yield of carbon dioxide formed from the reaction of 1.28 g of methane and 10.1 g of oxygen gas is 3.51 g.

The balanced equation for the reaction between methane (CH4) and oxygen gas (O2) to produce carbon dioxide (CO2) and water (H2O) is:

CH4 + 2O2 → CO2 + 2H2O

To find the theoretical yield of carbon dioxide, we need to calculate the moles of methane and oxygen and use the stoichiometry of the balanced equation.

Given: Mass of methane (CH4) = 1.28 g

Mass of oxygen gas (O2) = 10.1 g

Step 1: Calculate the moles of methane and oxygen using their molar masses:

Moles of CH4 = mass / molar mass = 1.28 g / 16.04 g/mol = 0.0798 mol

Moles of O2 = mass / molar mass = 10.1 g / 32.00 g/mol = 0.3156 mol

Step 2: Determine the limiting reactant (the reactant that is completely consumed first) by comparing the mole ratios of CH4 and O2 in the balanced equation. From the equation, for every 1 mol of CH4 there are 2 moles of O2 needed. Therefore, the mole ratio of CH4 to O2 is 1:2.

Since the mole ratio of CH4 to O2 is 1:2, and there are fewer moles of CH4 (0.0798 mol) compared to the moles of O2 (0.3156 mol), CH4 is the limiting reactant.

Step 3: Calculate the moles of CO2 produced using the mole ratio from the balanced equation:

Moles of CO2 = moles of CH4 x (1 mol of CO2 / 1 mol of CH4) = 0.0798 mol x (1 mol / 1 mol) = 0.0798 mol

Step 4: Convert the moles of CO2 to grams using the molar mass of CO2:

Mass of CO2 = moles x molar mass = 0.0798 mol x 44.01 g/mol = 3.51 g

Therefore, the theoretical yield of carbon dioxide formed from the reaction of 1.28 g of methane and 10.1 g of oxygen gas is 3.51 g (to the correct number of significant digits).

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Answer:

a) 2-chloro-2,3-dimethylbutane

b) 1-chloro-2,3-dimethylbutane

Explanation:

The monochlorination is a reaction in which we have to add only 1 Cl to the molecule. In this case, we will have to add a Cl to a primary carbon (a) and to a tertiary carbon (b).

In the monochlorination of the primary carbon, we can choose any methyl carbon. For the monochlorination of the terciary carbon we have to choose an CH carbon.

(See the figure)

Final answer:

When 2,3-dimethylbutane undergoes monochlorination under radical substitution conditions, multiple constitutional isomers can be formed due to the presence of primary and tertiary carbon atoms.

Explanation:

When 2,3-dimethylbutane undergoes monochlorination under radical substitution conditions, multiple constitutional isomers can be formed. The monochlorination reaction involves the substitution of a hydrogen atom on the carbon chain with a chlorine atom. Since 2,3-dimethylbutane has two different types of carbon atoms (primary and tertiary), the resulting constitutional isomers will also differ.

(a) Primary alkyl halide: The primary carbon atom is bonded to one other carbon atom and one hydrogen atom. So, a constitutional isomer could be formed by substituting the hydrogen atom with a chlorine atom.

(b) Tertiary alkyl halide: The tertiary carbon atom is bonded to three other carbon atoms. So, a constitutional isomer could be formed by substituting one of the carbon atoms with a chlorine atom.

Answer:

The molarity of the solution is 0.386 M

Explanation:

Step 1: Data given

Mass of NaCl = 7.88 grams

Volume of the solution = 350 mL

Molar mass of NaCl = 58.5 g/mol

Step 2: Calculate number of moles

Number of moles NaCl = mass of NaCl / molar mass of NaCl

Number of moles NaCl = 7.88 grams / 58.5 g/mol

Number of moles = 0.135 moles

Step 3: Calculate molarity of the solution

Molarity = Number of moles NaCl / volume

Molarity = 0.135 moles / 0.350 L

Molarity = 0.386 M

The molarity of the solution is 0.386M

Answer:

27.7 g

Explanation:

To solve this problem we use the definition of molarity:

From the problem we're given M = 2.5 M and volume = 0.100 L. We use the above formula and calculate the required moles of calcium chloride (CaCl₂):

Finally we use the molecular weight of calcium chloride to calculate the required mass:

Rounding to the nearest tenth of a gram the answer is 27.7 g.

To make a 2.5 M stock solution of calcium chloride, you would need to weigh out approximately 276.2 grams of calcium chloride.

To make a 2.5 M stock solution of calcium chloride, you need to calculate the number of grams of calcium chloride required. The molecular weight of calcium chloride is 110.98 g/mol. The formula to calculate the number of grams is:

Grams = Moles x Molecular Weight

Since you want to make 100 mL of a 2.5 M solution, you first need to convert mL to moles using the formula:

Moles = Volume (L) x Molarity (M)

Finally, you can substitute the calculated moles into the first formula to find the grams, and round to the nearest tenth of a gram.

Using these calculations, you would need to weigh out approximately 276.2 grams of calcium chloride to make the 2.5 M stock solution.

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Answer:

A carboxylate salt and water

Explanation:

A carboxylic acid is an organic compound that has general formula RCOOH, where R is a carbon chain. Because it's an acid, the neutralization will happen when it reacts with a base, such as NaOH.

When this reaction occurs, the base will dissociate in Na⁺ and OH⁻, and the acid will ionize in RCOO⁻ and H⁺, so the products will be RCOO⁻Na⁺ (a carboxylate salt) and H₂O (water).

Answer:

total mass will be =  = 1.207g

Explanation:

First what is given  

Pressure P= 0.988 atm                  Room TemperatureT = 23.5°C= 296.5 K

Volume V= 1.042 L

Nitrogen in air is 80 % (moles number) = 0.8                

Ideal gas constant R = 0.0821 L atmmol-1K-1

Given mass of N = 14.01 g/mol

Given mass of oxygen O = 16.00 g/mol

Total number of moles = ?

So first we have to find the total number of moles by using formula  

Total number of moles  

n = PV/ RT  

adding the values  

moles n= 0.988atm x 1.042L / (0.0821L-atm/mole-K x 296.6K)  

  = 1.0294 / 24.35

= 0.042 moles (total number of moles)

So by using Nitrogen percentage  

Moles of nitrogen = total moles x 80/100

                            = 0.042moles x 0.8  

So moles of O2= Total moles – moles of N2  

                       =   0.042moles - 0.034moles

    Moles of O2 = 0.008moles

Now for finding the mass of the N2 and oxygen  

Mass of Nitrogen N2 = no of moles x molar mass

                           = 0.034 x 28

                           = 0.952 g

Mass of oxygen O2 = no of moles x molar mass

                           = 0.008 x 32

                           =  0.256 g

total mass will be = Mass of Nitrogen N2 + Mass of oxygen O2  

                             =0.952 g  + 0.256 g

                               =1.207g

The mass of air in the flask = 1.207g

Given:

Pressure, P= 0.988 atm                  

Room Temperature, T = 23.5°C= 296.5 K

Volume, V= 1.042 L

Nitrogen in air is 80 % (moles number) = 0.8                

Ideal gas constant R = 0.0821 L atm [tex]mol^{-1}K^{-1}[/tex]

Molar mass of N = 14.01 g/mol

Molar mass of oxygen O = 16.00 g/mol

To find:

Total number of moles = ?

From ideal gas law:

n = PV/ RT  

n= 0.988atm * 1.042L / (0.0821 L atm [tex]mol^{-1}K^{-1}[/tex] * 296.6K)  

n  = 1.0294 / 24.35

n= 0.042 moles

Using mol fraction we will calculate moles for nitrogen and oxygen:

Moles of nitrogen = total moles * 80/100

Moles of nitrogen = 0.042moles * 0.8 = 0.034 moles

So, Moles of O₂ = Total moles – moles of N₂  

Moles of O₂ =   0.042 moles - 0.034 moles

Moles of O₂ = 0.008 moles

Calculation for mass:

Mass of Nitrogen N₂ = no of moles x molar mass

= 0.034 x 28

= 0.952 g

Mass of oxygen O₂ = no of moles x molar mass

= 0.008 * 32

=  0.256 g

Total mass will be = Mass of Nitrogen N₂ + Mass of oxygen O₂

=0.952 g  + 0.256 g

Total mass = 1.207g

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Answer:

Part-A:

Anode is Nickel and Cathode is copper.

Part -B:

[tex]E^{0}_{cell}[/tex] of the reaction is 0.567V.

Explanation:

Nickel-Copper cell electrodes are "Ni" and "Cu" rod.

Nickel electrode is dipped in [tex]Ni^{+2}[/tex] solution.

Copper electrode dipped in [tex]Cu^{+2}[/tex] solution.

Part -A:

Anode:

At anode oxidation takes place

[tex]Ni(s) \rightarrow Ni^{+2}(aq)+2e^{-}[/tex]

Hence, anode is Nickel.

Cathode:

At cathode reduction takes place.

[tex]Cu^{+2}+2e^{-} \rightarrow Cu(s)[/tex]

Hence, Cathode is copper.

Part-B:

[tex]E^{0}_{cell}=E^{0}_{cathode}-E^{0}_{anode}[/tex]

[tex]=0.337-(-0.230)=0.567V[/tex]

Hence, [tex]E^{0}_{cell}[/tex] of the reaction is 0.567V.

Anodes and cathodes are the electrodes where oxidation and reduction take place.

Electrochemical cells have two electrodes which is called anode and cathode. The anode is the electrode where oxidation occurs while the other hand, cathode is the electrode where reduction takes place so we can conclude that anodes and cathodes are the electrodes where oxidation and reduction take place.

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Answer:

F⁻(aq) + H⁺(aq) ⇄ HF(aq)

Explanation:

When aqueous solutions of potassium fluoride and hydrochloric acid are mixed, an aqueous solution of potassium chloride and hydrofluoric acid results. The corresponding molecular equation is:

KF(aq) + HCl(aq) ⇄ KCl(aq) + HF(aq)

The full ionic equation includes all the ions and the molecular species. HF is a weak acid so it exists mainly in the molecular form.

K⁺(aq) + F⁻(aq) + H⁺(aq) + Cl⁻(aq) ⇄ K⁺(aq) + Cl⁻(aq) + HF(aq)

The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the molecular species.

F⁻(aq) + H⁺(aq) ⇄ HF(aq)

Answer:

c) spontaneous

Explanation:

According the equation of Gibb's free energy -

∆G = ∆H -T∆S

∆G = is the change in gibb's free energy

∆H = is the change in enthalpy

T = temperature

∆S = is the change in entropy .

And , the sign of the  ΔG , determines whether the reaction is Spontaneous or non Spontaneous or at equilibrium ,

i.e. ,

if

From the question ,

The value for ΔG is negative ,

Hence ,

ΔG < 0 , the reaction is Spontaneous

Answer:

The molecular formula for the organic compound is C₈H₈O₂

Explanation:

70.58 % C , 5.9 % H , and 23.50 % O

This is a percent by mass, so:

in 100 g of compound I have 70.58 g of C, 5.9 g of H and 23.5 g of O.

We need to apply the formula for freezing point depression, the colligative property.

ΔT = Kf . m

Where ΔT means T°F (pure solvent) − T°F (solution)

Kf, the cryoscopic constant and m is molality (mol of solute in 1kg of solvent); Kf for cyclohexane is 20.8 °C/m

6.59°C - 3.29°C = 20.8 °C/m . m

3.3°C = 20.8 °C/m . m

3.3°C /20.8 m/°C = molal

0.158 m/kg

In 1kg of solvent I have 0.158 moles, but I have 718.1 g of cyclohexane

1000 g _____ 0.158 moles of solute

718.1 g _____ 0.114 moles of solute

To find out the molar mass of my compound I have to divide

mass/mol → 15.5 g /0.114 m = 136.04 g/m

Now I have to work with the percent and think this rules of three:

100 g of compound has ____ 70.58 g of C __5.9 g of H __23.5 g of O

136.04 g of compound has ___  96.02 g of C __8.02 g of H __ 32 g of O

Molar mass of C = 12 g/m

Molar mass of H = 1 g/m

Molar mass of O = 16 g/m

g / molar mass = moles

C: 96 g / 12 g/m = 8

H: 8 g / 1 g/m =8

O: 32 g/ 16 g/m = 2

The molecular formula for the organic compound is C₈H₈O₂

To find the molecular formula of the organic compound, calculate the empirical formula first, which is CH₃O. Then calculate the molar mass of the compound, which is 29g/mol. Divide the molar mass of the compound by the molar mass of the empirical formula to find the molecular formula ratio. The molecular formula is CH₃O.

To determine the molecular formula of the organic compound, we need to calculate the empirical formula first.

The percentages of carbon, hydrogen, and oxygen in the compound represent the mass ratios of these elements. Assume we have 100g of the compound, which means we have 70.58g of carbon, 5.9g of hydrogen, and 23.50g of oxygen. Now we convert these masses to moles using the molar masses: 12g/mol for carbon, 1g/mol for hydrogen, and 16g/mol for oxygen.

Next, we divide the moles of each element by the smallest number of moles to get the simplest mole ratio. The empirical formula of the compound is CH3O.

To find the molecular formula, we need to know the molar mass of the compound. This can be calculated by adding the atomic masses of the elements in the empirical formula: 12g/mol for carbon, 1g/mol for hydrogen, 16g/mol for oxygen. The sum is 29g/mol.

Since the molar mass of the compound is 29g/mol and 15.5g of the compound is dissolved in 718.1g of cyclohexane, we can calculate the moles of the compound: 15.5g / 29g/mol = 0.534moles.

The molecular formula is found by multiplying the empirical formula by an integer value to match the molar mass. To do this, divide the molar mass of the compound by the molar mass of the empirical formula: 29g/mol / 29g/mol = 1.

Therefore, the molecular formula of the organic compound is CH3O.

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Answer:

a. 5Cl₂ + 10e⁻  → 10Cl⁻

b. 4H₂O + Mn²⁺ → MnO₄⁻ + 5e⁻ + 8H⁺

Explanation:

5Cl2(g)+2Mn+2(aq)+8H2O(l)→ 10Cl−(aq)+2MnO4-(aq)+16H+(aq)

First of all, think in all the oxidation numbers for each compound. That's the way, you can notice the half reaction.

When the oxidation number, decrease, you have reduction. Compound is wining electrons.

When the oxidation number increase, you have oxidation. Compound is losing electrons.

Cl2(g) - Atoms in ground state, has 0 as oxidation number. In products side, you have the anion chloride which act with -1, so chlorine has been reduced.

Mn2+ - The manganese ion is already telling you with 2, that is its oxidation number. On the side products, the element was transformed into the permanganate anion; how oxygen acts with -2 and there are 4 atoms, it has -8 as oxidation state but since the general charge is -1 the Mn is acting with +7.  From + 2 it went to +7, which means that it increased, so it has oxidized.

5Cl₂ + 10e⁻  → 10Cl⁻  - REDUCTION

The chlorine had to gain 1 electron to go from 0 to -1, but being a diatomic molecule were 2 electrons, but finally so that the charges are balanced and because there are 5 moles, it ends up gaining 10 electrons.

Mn²⁺ → MnO₄⁻ - OXIDATION

Look that in main reaction we have H⁺, that is the clue to notice us, that we are in acidic medium. So if we have 4 O, in MnO₄⁻, we have to complete with 4H₂O in the other side of O. And to ballance the protons, we have to add 8H⁺ in product side

4H₂O + Mn²⁺ → MnO₄⁻ + 5e⁻ + 8H⁺ OXIDATION

How do u finish this?. You have to multipply .2, the oxidation one to balance the e⁻ so, they can be cancelled.

5Cl₂ + 10e⁻  → 10Cl⁻

(4H₂O + Mn²⁺ → MnO₄⁻ + 5e⁻ + 8H⁺ ).2

8H₂O + 2Mn²⁺ → 2MnO₄⁻ + 10e⁻ + 16H⁺

5Cl₂ + 10e⁻ + 8H₂O + 2Mn²⁺ → 10Cl⁻ + 2MnO₄⁻ + 10e⁻ + 16H⁺

5Cl₂  + 8H₂O + 2Mn²⁺ → 10Cl⁻ + 2MnO₄⁻  + 16H⁺

The half-reactions for the given redox reaction includes the reduction of Mn2+(aq) to MnO4-(aq) with the addition of 5 electrons and 8 hydrogen ions and the oxidation of Cl2(g) to 10 Cl-(aq), losing 10 electrons in the process.

The redox reaction is related to the process of reduction and oxidation which often takes place in electrochemical cells. This process includes half-reactions, which separately represent the oxidation and reduction in the redox reaction. For the given equation, the oxidation and reduction half-reactions are as follows:

a. Reduction: Mn2+(aq) + 5e- + 8H+(aq) → MnO4-(aq) + 4H2O(l).

b. Oxidation: Cl2(g) → 10e- + 10Cl-(aq).

These equations represent the transformation of Mn2+ and Cl2 in the given redox reaction where Mn2+ is being reduced and Cl2 is being oxidized.

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Answer:

0,07448M of phosphate buffer

Explanation:

sodium monohydrogenphosphate (Na₂HP) and sodium dihydrogenphosphate (NaH₂P) react with HCl thus:

Na₂HP + HCl ⇄ NaH₂P + NaCl (1)

NaH₂P + HCl ⇄ H₃P + NaCl (2)

The first endpoint is due the reaction (1), When all phosphate buffer is as NaH₂P form, begins the second reaction. That means that the second endpoint is due the total concentration of phosphate that is obtained thus:

0,01862L of HCl×[tex]\frac{0,1000mol}{L}[/tex]= 1,862x10⁻³moles of HCl ≡ moles of phosphate buffer.

The concentration is:

[tex]\frac{1,862x10^{-3}moles}{0,02500L}[/tex] = 0,07448M of phosphate buffer

I hope it helps!

Answer:

The standard potential for this galvanic cell is 1.25 V

Explanation:

Step 1

Oxidation: Fe(s) → Fe^2+ (aq) + 2e-     E° = 0.447 V

Reduction: Ag+(aq) + e- → Ag(s)          E° = 0.7996 V

The electron number for the oxidation is 2; the electron number for the reduction is 1.

By multiplying the reduction reaction by 2, we make the electron number the same between the two half-equations

2 Ag+(aq) + 2e- → 2Ag(s)          E° = 0.7996 V

Step 2: The overall balanced equation

Fe(s) + 2Ag+(aq) → Fe^2+(aq) + 2ag(s)   E° = 0.447 V + 0.7996 V = 1.25V

The standard potential for this galvanic cell is 1.25 V

Answer:

B

Explanation:

Diamagnetism , paramagnetism and ferromagnetism are terms which are used to describe the magnetic activity of transition metals. These terms helps to know the response the metal will have when placed in a magnetic field. These activities can be discerned from the d-block electronic configuration. If the number of electrons are even, this means they all form a pair and the metal is diamagnetic. If otherwise, there is an unpaired electron which causes the paramagnetic activity of the metal in magnetic field.

To the question, options A-D are diamagnetic but configurations with d8 are the ones that form square planar complexes

Answer:

Correct option -D

Explanation:

Mass defect:

The difference between the sum of the masses of individual nucleons that form an atomic nucleus and the mass of the nucleus.

Hence, i- is correct

Nuclear fission:

It is the process of splitting a nucleus into two nuclei with smaler masses.

Hence, ii- is correct

Nuclear fission involved bombarding with nuclei [tex]^{235}_{92}U[/tex] with [tex]^{4}_{2}He[/tex]

Nuclear fission of [tex]^{235}_{92}U[/tex] with neutrons forms two smaller mass nuclei.

[tex]^{1}_{0}n+^{235}_{92}U \rightarrow ^{91}_{36}Kr+^{142}_{56}B+3^{1}_{0}n+Energy[/tex]

Hence, iii- is incorrect

Therefore, option -D is correct

Statements i) and ii) are correct. Mass defect refers to the difference in mass between that of a nucleus and the sum of the masses of its component nucleons. Nuclear fission refers to the splitting of a heavier nucleus into two nuclei with smaller mass numbers.

The correct statement(s) from the ones provided are: i) Mass defect is the difference in mass between that of a nucleus and the sum of the masses of its component nucleons. This is because the mass of a nucleus is not just the sum of the individual masses of the protons and neutrons. Some mass is converted into energy to provide the binding force that holds the nucleus together, so the mass of the nucleus has a slight deficit (or defect) compared to the combined masses of its components.

ii) Nuclear fission involves the splitting of a heavier nucleus into two nuclei with smaller mass numbers. This process usually does not occur naturally, but is induced by bombardment with neutrons. The first reported nuclear fission occurred in 1939 when uranium-235 atoms were bombarded with slow-moving neutrons that split the uranium nuclei into smaller fragments.

Thus, the correct option is D. i) and ii) only.

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Answer:

a. 750Hz, b. 4.0ppm, c. 600Hz

Explanation:

The Downfield Shift (Hz) is given by the formula

Downfield Shift (Hz) = Chemical Shift (ppm) x Spectrometer Frequency (Hz)

Using the above formula we can solve all three parts easily

a. fspec = 300 MHz, Chem. Shift = 2.5ppm, 1MHz = 10⁶ Hz, 1ppm (parts per million) = 10⁻⁶

Downfield Shift (Hz) = 2.5ppm x 300MHz x (1Hz/10⁶MHz) x (10⁻⁶/1ppm)

Downfield Shift = 750 Hz

The signal is at 750Hz Downfield from TMS

b. Downfield Shift = 1200 Hz, Chemical Shift = ?

Chemical Shift = Downfield shift/Spectrometer Frequency

Chemical Shift = (1200Hz/300MHz) x (1ppm/10⁻⁶) = 4.0 ppm

The signal comes at 4.0 ppm

c. Separation of 2ppm, Downfield Shift = ?

Downfield Shift (Hz) = 2(ppm) x 300 (MHz) x (1Hz/10⁶MHz) x (10⁻⁶/1ppm) = 600 Hz

The two peaks are separated by 600Hz

Explanation:

[tex]4 Fe(s) + 3O_2(g)\rightarrow 2Fe_2O_3(s) ,\Delta H = -1652 kJ[/tex]

a) Heat released when 4.48 moles of iron is reacted with excessive oxygen:

According to reaction, when 4 moles of an iron reacts with 3 moles of oxygen it gives 1625 kilo Joules of heat.

Then 4.48 moles of iron will give:

[tex]\frac{1652 kJ}{4}\times 4.48=1850.24 kJ[/tex]

1850.24 kJ of heat is released when 4.48 moles of an iron is reacted with excess oxygen.

b) Heat released when 1.76 mol [tex]Fe_2O_3[/tex] is produced.

According to reaction, when 2 moles of an [tex]Fe_2O_3[/tex] are produced 1625 kilo Joules of heat is released

Then heat released on production of 1.76 mol [tex]Fe_2O_3[/tex] :

[tex]\frac{1652 kJ}{2}\times 1.76=1453.76 kJ[/tex]

1453.76 kJ heat is released when 1.76 mol [tex]Fe_2O_3[/tex] is produced.

c) Heat released when 2.66 grams of iron is reacted with excessive oxygen:

Moles of iron = [tex]\frac{2.66 g}{56 g/mol}=0.0475 mol[/tex]

According to reaction, when 4 moles of an iron reacts with 3 moles of oxygen it gives 1625 kilo Joules of heat.

Then 0.0475 moles of iron will give:

[tex]\frac{1652 kJ}{4}\times 0.0475=19.62 kJ[/tex]

19.62 kJ of heat is released when 2.66 grams of iron is reacted with excessive oxygen.

d) Heat released when 12.8 g Fe and 1.49 g oxygen gas are reacted:

Moles of iron = [tex]\frac{12.8 g}{56 g/mol}=0.2286 mol[/tex]

According to reaction, 4 moles of iron reacts with 3 moles of oxygen.Then 0.2286 mol will react with:

[tex]\frac{3}{4}\times 0.2286 mol=0.17145 mol[/tex] of oxygen

Moles of oxygen = [tex]\frac{1.49 g}{56 g/mol}=0.04656 mol[/tex]

According to reaction, 3  moles of oxygen gas reacts with 4 moles of iron .Then 0.04656 mol will react with:

[tex]\frac{4}{3}\times 0.04656 mol=0.06208 mol[/tex] of iron.

From this we can conclude that oxygen is in limiting amount. So, the amount of energy release will depend upon moles of oxygen gas.

According to reaction, when 4 moles of an iron reacts with 3 moles of oxygen it gives 1625 kilo Joules of heat.

Then 0.04656 moles of oxygen gas will give:

[tex]\frac{1652 kJ}{3}\times 0.04656 =25.7011 kJ[/tex]

25.7011 kJ of Heat is released when 12.8 g Fe and 1.49 g oxygen gas are reacted

The heat released in an exothermic reaction can be calculated using stoichiometry based on the ΔH value. The released heat varies with the amount of reactant or product involved. By calculating the molar ratios, the heat released is computed for each sub-question accordingly.

The reaction you provided loosens heat, hence it is an exothermic reaction. The heat released can be calculated using stoichiometry if we know the amount of reactants or products. ΔH (-1652 kJ) is the amount of heat released for the reaction of 4 moles of Fe with 3 moles of O2 to form 2 moles of Fe2O3.

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Answer: 0.94 V

Explanation:

For the given chemical reaction :

[tex]Zn(s)+Cu^{2+}(aq)\rightarrow Cu(s)+Zn^{2+}[/tex]

Using Nernst equation :

[tex]E_{cell}=E^o_{cell}-\frac{2.303RT}{nF}\log \frac{[Zn^{2+}]}{[Cu^{2+}]}[/tex]

where,

F = Faraday constant = 96500 C

R = gas constant = 8.314 J/mol.K

T = room temperature = [tex]298K[/tex]

n = number of electrons in oxidation-reduction reaction = 2

[tex]E^o_{cell}[/tex] = standard electrode potential of the cell = +1.10 V

[tex]E_{cell}[/tex] = emf of the cell = ?

Now put all the given values in the above equation, we get:

[tex]E_{cell}=+1.10-\frac{2.303\times (8.314)\times (298)}{2\times 96500}\log \frac{2.5}{1.0\times 10^{-5}}[/tex]

[tex]E_{cell}=+1.10-0.16V=0.94V[/tex]

The cell potential for this reaction is 0.94 V

The cell potential for the given reaction depends on the concentration of the reactants. We can use the Nernst equation to calculate the cell potential when the concentration of [Cu2+]=1.0⋅10−5M and [Zn2+]=2.5M.

The standard cell potential (E°cell) for the given reaction is +1.10V. To find the cell potential for this reaction when the concentrations of [Cu2+]=1.0⋅10−5M and [Zn2+] = 2.5M, we need to use the Nernst equation:

Ecell = E°cell - (0.0592/n) x log(Q)

Here, n is the number of electrons involved in the reaction, and Q is the reaction quotient, which is equal to [Zn2+]/[Cu2+]. In this case, n = 2. Plugging in the values, we get:

Ecell = 1.10V - (0.0592/2) x log((2.5M)/ (1.0⋅10−5M))

Solving this equation will give us the cell potential for the given concentrations.

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Answer:

∆H°rxn in kJ/mol AgCl = - 59.61 kJ/mol

Explanation:

To solve this question we need to calculate the heat absorbed by the cup calorimeter and by the water in the solutions. We will also need to calculate the amount in moles produced by the reaction since we want to know the ∆H°rxn in kJ/mol AgCl .

mol AgNO₃ = 100 mL x 1L/1000 mL x 0.100 mol/L = 0.01 mol

mol NaCl = 100 mL x 1L/1000 mL x 0.200 mol/L = 0.02 mol

Therefore our limiting reagent is the 0.01 mol AgNO₃ and 0.01 mol AgCl will be produced according to the stoichiometry of the reaction:

AgNO₃ + NaCl ⇒ AgCl + NaNO₃

Heat absorbed by the water:

qw = m(H₂O) x c x ΔT where  m (H₂O) = 200 g ( the density of final solution is  1  g/ml)

c = specific heat of water = 4.18 J/gºC

ΔT = change in temperature =  (25.30 - 24.60 ) ºC = 0.7ºC

qw = 200 g x 4.18 J/gºC x 0.7 ºC = 585.20 J

Heat Absorbed by the calorimeter :

q cal = C cal x  ΔT  = 15.5 J/ºC x 0.7ºC = 10.85 J

Total Heat released by the combustion = qw + qcal = 585.20 J +10.85 J

=  596.05 J

We have to change the sign to this quantity since it is an exotermic reaction  ( ΔT is positive ) and have the ∆Hrxn

∆H rxn  = -596.05 J  

but this  is not what we are being asked since this heat was released by the formation of  0.0100 mol of AgCl so finally  

∆H°rxn = -596.05 J /0.01 mol  = -59,605 J/mol x 1 kJ/1000J = -59.61 kJ/mol

Answer:

Explanation:

Use gas equation to calculate mol of H2O gas:  

P = pressure = 389/760 = 0.512atm  

V = volume = 4L  

n=???

R = 0.082057

T = 121+273 = 394K  

0.512 * 4 = n*0.082057*394

n = (0.512*4) / (0.082057*394)  

n = 2.048 / 32.33

n = 0.063 mol H2O  

Molar5 mass H2O = 18g/mol  

Mass of water = 0.063*18

Mass of water valour = 1.14g

Answer: The chemical equation is written below.

Explanation:

Transmutation is defined as the process in which one chemical isotope gets converted to another chemical isotope. The number of protons or neutrons in the isotope gets changed.

The chemical equation for the reaction of curium-242 nucleus with alpha particle (helium nucleus) follows:

[tex]_{96}^{242}\textrm{Cm}+_4^2\textrm{He}\rightarrow _{98}^{245}\textrm{Cf}+_0^1\textrm{n}[/tex]

The product formed in the nuclear reaction are californium-245 nucleus and a neutron particle.

Answer:

The percentage  by mass of water in magnesium sulfate heptahydrate is 51.2 %

Explanation:

Step 1: Data given

Molar mass of MgSO4*7H2O = 246.5 g/mol

Molar mass of H2O = 18.02 g/mol

Molar massof MgSO4 = 120.37 g/mol

Step 2: Calculate % water in magnesium sulfate heptahydrate

Since we have 7 molecules of water in the heptahydrate, we will divide the molar mass of 7 molecules water by the molar mass of the heptahydrate.

m%(H2O) = (7*18.02)/ 246.5

m%(H2O) = (126.14 /246.5)*100%

m%(H2O) = 51.2 %

To controle this we will calculate the mass % of MgSO4

m%(MgSO4) = (120.37/ 246.50)*100%

m%(MgSO4) = 48.8%

51.2 + 48.8 = 100%

The percentage  by mass of water in magnesium sulfate heptahydrate is 51.2 %

Answer:from reffered dfn of %by mass

%by M=mass of component particular/total mass

But mass directly proportional to Molar mass

% by M=molar mass of H2O cpn/total M

%by M=7((1×2)+16)/(7((1×2)+16)+(24+(16×4)+32))

=0.573

Answer:

c. 8, product side

Explanation:

In order to balance a redox reaction we use the ion-electron method, which has the following steps:

Step 1: identify oxidation and reduction half-reaction.

Oxidation: MnO₄⁻(aq) → Mn²⁺(aq)

Reduction: Br⁻(aq) → Br₂(l)

Step 2: perform the mass balance adding H⁺ and H₂O where necessary

8 H⁺(aq) + MnO₄⁻(aq) → Mn²⁺(aq) + 4 H₂O(l)

2 Br⁻(aq) → Br₂(l)

Step 3: perform the electrical balance adding electrons where necessary.

8 H⁺(aq) + MnO₄⁻(aq) + 5 e⁻ → Mn²⁺(aq) + 4 H₂O(l)

2 Br⁻(aq) → Br₂(l) + 2 e⁻

Step 4: multiply both half-reactions by numbers that secure that the number of electrons gained and lost are the same.

2 × (8 H⁺(aq) + MnO₄⁻(aq) + 5 e⁻ → Mn²⁺(aq) + 4 H₂O(l))

5 × (2 Br⁻(aq) → Br₂(l) + 2 e⁻)

Step 5: add both half-reactions side to side.

16 H⁺(aq) + 2 MnO₄⁻(aq) + 10 e⁻ + 10 Br⁻(aq) → 2 Mn²⁺(aq) + 8 H₂O(l) + 5 Br₂(l) + 10 e⁻

16 H⁺(aq) + 2 MnO₄⁻(aq) + 10 Br⁻(aq) → 2 Mn²⁺(aq) + 8 H₂O(l) + 5 Br₂(l)

The chemical equation for the neutralization of hydroxide ion by HClO is:

A buffer is a solution which resists changes to its pH when a small quantity of strong acid or base is added to it.

A solution of weak acid such as hypochlorous acid (HClO) and its basic salt that is sodium hypochlorite (NaClO) forms a buffer solution

When a strong base is added to the buffer, the excess hydroxide ion will be neutralized by hydrogen ions from the acid, HClO.

The chemical equation for the neutralization of hydroxide ion with acid follows:

Therefore, the balanced chemical equation is such that the excess OH- is neutralized.

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