Question 3 of 10
What is the pOH of a solution with [OH] = 9.0 × 107?
O A. 7.95
OB. 6.04
O C. -7.00
OD. 9.54

Answer:

10 L

Explanation:

The equation of the reaction is;

2BaO2 = 2BaO + O2

Number of moles of  BaO2 = 114.7 g/169.33 g/mol = 0.677 moles

From the reaction equation;

2 moles of BaO2 yields 1 moles of O2

0.677 moles of BaO2 yields 0.677 * 1/2 = 0.3385 moles of oxygen

Hence;

PV=nRT

V = ?

P = 127400 Pa or 1.257 atm

T = 455 K

n = 0.3385 moles

R = 0.082 atmLmol-1K-1

V = nRT/P

V = 0.3385 * 0.082 * 455/1.257

V= 10 L

The freezing point of the solution is -11.8 °C.

The boiling point of the solution is 103.31 °C.

To determine the freezing point of the solution, we can use the equation:

ΔTf = Kf * m

where:

ΔTf is the freezing point depression,

Kf is the cryoscopic constant (for water, Kf = 1.86 °C/m),

m is the molality of the solution (moles of solute per kilogram of solvent).

First, let's calculate the molality (m) of the solution:

Molar mass of ethylene glycol (C2H6O2):

C = 12.01 g/mol

H = 1.01 g/mol (x 6) = 6.06 g/mol

O = 16.00 g/mol (x 2) = 32.00 g/mol

Total molar mass = 12.01 g/mol + 6.06 g/mol + 32.00 g/mol = 50.07 g/mol

Number of moles of ethylene glycol (C2H6O2) = mass / molar mass

Number of moles = 30.8 g / 50.07 g/mol = 0.615 mol

Mass of water = volume x density = 96.6 mL x 1.00 g/mL = 96.6 g

Now, let's calculate the molality:

Molality (m) = moles of solute / mass of solvent (in kg)

Molality = 0.615 mol / 0.0966 kg = 6.36 mol/kg

Now we can calculate the freezing point depression (ΔTf):

ΔTf = Kf * m

ΔTf = 1.86 °C/m * 6.36 mol/kg = 11.8 °C

To find the freezing point of the solution, subtract the freezing point depression from the freezing point of pure water (0 °C):

Freezing point = 0 °C - 11.8 °C = -11.8 °C

To determine the boiling point of the solution, we can use the equation:

ΔTb = Kb * m

where:

ΔTb is the boiling point elevation,

Kb is the ebullioscopic constant (for water, Kb = 0.52 °C/m),

m is the molality of the solution (same value as calculated before: 6.36 mol/kg).

ΔTb = 0.52 °C/m * 6.36 mol/kg = 3.31 °C

To find the boiling point of the solution, add the boiling point elevation to the boiling point of pure water (100 °C):

Boiling point = 100 °C + 3.31 °C = 103.31 °C

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Answer:

Part A

La tensión en la cadena es de aproximadamente 364,14 Newtons

Part B

La fuerza con la que se empuja el columpio es de aproximadamente 327,874 Newtons

Explanation:

Parte A

Los parámetros dados son;

La masa del asiento en el que se sienta el niño = 15 kg

La inclinación de la cadena de la vertical, θ = 42 °

La masa del niño = 35 kg

La aceleración debida a la gravedad, g = 9,8 m / s²

La tensión en la cuerda, 'T', se da de la siguiente manera;

T = m · g · cos (θ)

Dónde;

m = m₁ + m₂ = 15 kg + 35 kg = 50 kg

g = La aceleración debida a la gravedad = 9,8 m / s²

θ = 42 °

Por lo tanto;

T = 50 kg × 9,8 m / s² × cos (42 °) ≈ 364,14 N

La tensión en la cadena, T ≈ 364.14 N

Parte B

La fuerza con la que se empuja el columpio, 'F', se da de la siguiente manera;

F = m · g · sin (θ)

Por lo tanto;

F ≈ 50 kg × 9,8 m / s² × sen (42 °) ≈ 327,874 N

La fuerza con la que se empuja el columpio, F ≈ 327,874 N.

The volume of HCl gas required to react with excess magnesium metal to produce 6.82 L of hydrogen gas at 2.19 atm and 35.0 °C is 4.32 L.

Magnesium is a chemical element with symbol Mg and atomic number 12. It is a silvery-white, highly reactive metal and is the eighth most abundant element in Earth’s crust. Magnesium is an important component of proteins, nucleic acids, enzymes, and many other vital biological compounds.

The ideal gas law, PV=nRT, can be used to calculate the volume of HCl gas required to react with excess magnesium metal to produce 6.82 L of hydrogen gas at 2.19 atm and 35.0 °C.
First, the number of moles of hydrogen gas can be calculated using the ideal gas law:

n = PV/RT = (2.19 atm)(6.82 L)/[(0.082 L atm/mol K)(308.15 K)] = 0.077 mol

Next, the number of moles of HCl required to produce 0.077 mol of hydrogen can be calculated using the mole ratio of the balanced equation:

2 mol HCl : 1 mol H₂

0.077 mol H₂ x (2 mol HCl/1 mol H₂) = 0.154 mol HCl

Finally, the volume of HCl gas required can be calculated using the ideal gas law:

V = nRT/P = (0.154 mol)(0.082 L atm/mol K)(308.15 K)/(2.19 atm) = 4.32 L

Therefore, the volume of HCl gas required to react with excess magnesium metal to produce 6.82 L of hydrogen gas at 2.19 atm and 35.0 °C is 4.32 L.

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Answer:

a stable subatomic particle with a charge of negative electricity, found in all atoms and acting as the primary carrier of electricity in solids.

mass: 9.1093837015 × 10−31 kg

charges: fundamental physical constant expressing the naturally occurring unit of electric charge, equal to 1.602176634 × 10−19 coulomb.

Explanation:

good luck !<3

Answer:

a.

\([H _{3}O {}^{ + } ] = 4.23 \times {10}^{ - 3} M\)

b.

\([OH {}^{ - } ] = \frac{kw}{[H {}^{ + } ]} \\ [OH {}^{ - } ] = \frac{1 \times {10}^{ - 14} }{4.23 \times {10}^{ - 3} } \\ [OH {}^{ - } ] = 2.36 \times {10}^{ - 12} M\)

c.

\(pH = - log[H {}^{ + } ] \\ pH = - log(4.23 \times {10}^{ - 3} ) \\ pH = 2.37\)

d.

\(pOH = - log[OH {}^{ - } ] \\ = - log(2.36 \times {10}^{ - 12} ) \\ = 11.63\)

Answer:

Please find attached the completed Lewis dot diagram structure for PI₂F

Explanation:

The number of valence electrons are;

Phosphorus = 5 Electrons

Iodine = 2 × 7 electrons = 14 electrons

Chlorine = 7 electrons

The total number of valence electrons = 14 + 7 + 5 = 26 electrons

2) We draw the symbol that represents the basic (general) structure of the molecule as follows;

The sheared electron pair are represented by single bond lines

3) We complete the octet structures round the fluorine and the iodine atoms as attached showing 18 electrons plus 6 shared electron pairs, with a maximum from step 2 to give a total of (18 + 6) 24 electron pairs

4) We add the 2 unaccounted valence electron on the phosphorus atom to give it the stable octet structure, which gives the completed Lewis structure

Exothermic refers to the process that produces heat. The correct response is thus d) exothermic.

Exothermic describes a chemical or physical reaction that produces heat or light as a byproduct. An exothermic reaction raises the temperature of the environment by releasing energy from the reactants to it. Combustion, oxidation, and neutralisation are a few examples of exothermic reactions. The opposite of endothermic processes, which draw energy from the environment and reduce temperature, is an exothermic reaction. Several chemical and industrial operations, including the creation of heat in power plants and the manufacture of steel, depend on exothermic reactions.

Examples of exothermic reactions are as follows:

Exothermic processes include the burning of fuels like wood, coal, and gasoline. that causes energy to be released as heat and light.

Reactions between acids and bases that produce salt and water and release energy are known as neutralisation reactions.

Reactions known as polymerization: Reactions known as polymerization involve connecting monomers to produce polymers and frequently release energy in the process.

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Answer:

The large relative distances between particles in a gas means that there is considerable empty space between the particles.

The assumption that particles in a gas are relatively far apart explains gas compressibility.

Compressibility is a measure of how much the volume of matter decreases under pressure.

Energy is released by a gas when it is compressed

Explanation:

The kinetic molecular theory establishes that gases are composed of molecules. These molecules of gas are far apart from each other hence there is a considerable empty space between the gas molecules. As a result of these empty spaces between gas molecules, it is possible to compress a gas.

Compressibility is defined as a measure of how much the volume of matter decreases under pressure. When a gas is compressed, work is done on the gas and energy is evolved hence the gas heats up.

Answer:c is correct

Explanation:

The student collected 10 g of water vapor during the experiment.

The mass of the water vapor the student collected can be found using the law of conservation of mass, which states that the mass of a closed system remains constant over time, as long as there is no addition or removal of matter.

In this case, the closed system is the test tube, which initially contained 30 g of water and nothing else. When the water was heated to boiling, some of it evaporated and became water vapor, which was then collected through the tube placed in the bung of the test tube. Since the system was closed and no other matter was added or removed, the total mass of the system must remain constant.

Therefore, we can use the conservation of mass to determine the mass of the water vapor collected:

Initial mass of system (water) = 30 g

Final mass of system (water + water vapor) = 20 g

Since the mass of the system must remain constant, the mass of the water vapor collected is:

Mass of water vapor = initial mass of system - final mass of system

Mass of water vapor = 30 g - 20 g

Mass of water vapor = 10 g

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The correct answer is:

Keq<1, ΔG∘>0

When a system is at equilibrium, the forward and reverse reactions occur at equal rates. At this point, the concentrations of the reactants and products do not change over time. The equilibrium constant (Keq) is a measure of the relative concentrations of the reactants and products at equilibrium.

If the reactants are more abundant at equilibrium, it means that the equilibrium lies towards the side of the reactants. This suggests that the value of Keq is less than 1, since the ratio of products to reactants is low. Additionally, a positive ΔG∘ (standard free energy change) indicates that the reaction is not spontaneous in the forward direction, meaning that energy must be added to the system to proceed in that direction.

Therefore, the correct statement is: Keq<1, ΔG∘>0.

It's important to note that this answer assumes standard conditions (25°C, 1 atm pressure, and 1 M concentration). At different temperatures and concentrations, the values of Keq and ΔG∘ may change.

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The statement “the yeast engages in photosynthesis, which produces oxygen gas” is incorrect. Yeast cells do not engage in photosynthesis to produce oxygen gas.

Photosynthesis is the process by which green plants use sunlight, carbon dioxide, and water to produce glucose (a simple sugar), which serves as food for the plant.

Oxygen is also produced during photosynthesis.Yeast:Yeast is a unicellular fungus that converts sugar into carbon dioxide and alcohol. Yeast cells respire aerobically in the presence of oxygen and anaerobically in the absence of oxygen.

However, yeast cells do not perform photosynthesis. They do not have chloroplasts or pigments that are required for photosynthesis. Therefore, yeast cells cannot produce oxygen gas.Bio quizlet:Quizlet is an online learning platform that allows users to create and share flashcards, study guides, and quizzes.

It is a great resource for studying biology and other subjects. Students can create their own study materials or use existing ones created by other users. Quizlet provides an engaging and interactive way to learn and retain information.

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Answer:

222

Explanation:

because

2x + 78 = 222

2 (72) + 78

2 x 72 = 144

144 + 78 = 222

Where x is you multiply what x equals by the number on the left of it

The oxygen ion is commonly abbreviated as O2. As a result, the charge produced when oxygen forms an ion is 2

With an electron configuration of (2, 6), oxygen requires two electrons to occupy the n=2 energy level and achieve an octet of electrons in the outermost shell. As a result of acquiring two electrons, the oxide ion will have a charge of two.

We have one, two, three, four, five, and six valence electrons around the oxygen in our illustration, thus six minus six equals zero, and the formal charge on oxygen is zero.

Oxygen normally contains two bonds, but it can have three. If the O has three bonds, it is positively charged. An oxygen atom will frequently have only one link, however the oxygen atom will be negatively charged. Polyatomic ions are prominent outliers to the rule that halogens have only one bond.

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The amount of heat energy lost when 217 grams of gold cools from 125.0 °C to 77.0 °C is -1312 J

First, we shall list out the given parameters from the question. This is shown below:

Q = MCΔT

Inputting the given parameters, we can obtain the heat energy lost as follow:

Q = 217 × 0.126 × -48

Q = -1312 J

Thus, from the above calculation, we can conclude that the heat energy lost is -1312 J

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Answer: There are 2.161 x 10^24 molecules present in 3.6 moles CH₁.

Explanation:

Molecules are the the lowest fundamental unit of a chemical molecule that can participate in a chemical reaction is a group of bound atoms. Avogadro's number is used to calculate the number of molecules present in a mole of a substance

Avogadro's number of particles, or around 6.022 x 1023 molecules, are present in one mole of any substance. Therefore the following would be present in 3.6 moles of CH1:

2.161 x 1024 particles are equal to 3.6 moles times 6.022 x 1023 particles per mole.

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Answer:

One molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom. Water is a tasteless, odorless liquid at ambient temperature and pressure.

Explanation:

Hope this helps :) Have a great day!

When 31 moles of CH3COO- are oxidized to CO2, 31 moles of electrons are transferred from carbon to sulfur.

The balanced equation for the overall reaction can be obtained by multiplying the first half-reaction by 1 and the second half-reaction by 8, so that the electrons cancel out:

8CO2 + 8SO42- + 8H+ -> 8CH3COO- + H2S

From the balanced equation, we can see that for every 8 moles of CH3COO- oxidized (which is equivalent to 8 moles of CO2 produced), 1 mole of H2S (Hydrogen Sulfide) is formed.

Given that you want to oxidize 31 moles of CH3COO-, we can determine the moles of electrons transferred from carbon to sulfur:

31 moles CH3COO- * (1 mole H2S / 8 moles CH3COO-) = 3.875 moles of H2S

Since the balanced equation shows that for every mole of H2S formed, 8 moles of electrons are transferred, we can multiply the number of moles of H2S by 8:

3.875 moles H2S * 8 moles e-/1 mole H2S = 31 moles of electrons transferred from carbon to sulfur.

Therefore, 31 moles of electrons are transferred from carbon to sulfur when 31 moles of CH3COO- are oxidized to CO2.

Full Question:

Below are the half reactions for sulfate reduction using acetate as a source of electrons, energy, and carbon.

CO2 + 8e- -> CH3COO- (E0 = -0.29 volts)

SO42- + 8e- -> H2S (E0 = -0.22 volts)

If you balance and combine the reactions so that 31 moles of CH3COO- are oxidized to CO2, how many moles of electrons are transferred from carbon to sulfur?

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Answer:

Density, \(d=2.09\ g/cm^3\)

Explanation:

Given that,

Mass of a flask is 450 g

Volume of benzene added to the flask is 145 mL or 145 cm³

The weight of the flask and benzene is found to be 754 g.

We need to find the density of the benzene.

Weight of benzene added = total weight of flask and benzene-mass of flask

m = 754 g - 450 g

m = 304 g

Density = mass/volume

So,

\(d=\dfrac{304\ g}{145\ cm^3}\\\\d=2.09\ g/cm^3\)

So, the density of the benzene is \(2.09\ g/cm^3\).

Answer:

Al + 3NaOH  = Al(OH)₃ +3Na

Explanation:

The reaction is given as:

            Al + NaOH  = Al(OH)₃ + Na

This reaction is called a single displacement reaction in which one specie displaces another from a solution.

 To balance the equation:

                aAl + bNaOH  = cAl(OH)₃ + dNa

a, b, c and d are the coefficient that will balance the equation:

     Conserving Al;

                 a = c

     Conserving Na;

                b  = d

     Conserving O;

                 b  = 3c

     Conserving H;

                b = 3c

Let a  = 1, c = 1, b = 3 and d = 3

             Al + 3NaOH  = Al(OH)₃ +3Na

The solubility (in g/l) of caso4(s) in 0.300 m na2so4(aq) at 25°c is 0.016762 g/mol.

Solubility is defined as the maximum amount of a substance in an effort to dissolve in a given quantity of solvent at a special temperature. Solubility is a characteristic asset of a particular solute-solvent combination, and special substances have significantly differing solubilities.

Solubility of CaSO₄; K_sp = 4.93 × 10⁻⁵

Concentration of Na₂SO₄ = 0.4 M

The ionic equation of CaSO₄ is given as;

CaSO₄ ⇒ Ca²⁺ + SO₄²⁻

Now, the formula for solubility ,

K sp = [A⁺]ᵃ × [B⁻]ᵇ

Thus, plugging in relevant values into the solubility equation -

4.93 × 10⁻⁵ = Ca²⁺ × 0.4

Ca²⁺ = ( 4.93 × 10⁻⁵)/0.4

Concentration of Ca²⁺ = 12.325 × 10⁻⁵ M

The molar mass of CaSO₄ =  136 g

Hence, solubility of CaSO₄ in 0.4M of Na₂SO₄ is 12.325 × 10⁻⁵ M × 136 g/mol = 0.016762 g/mol

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Answer:

Physical change

Explanation:

It is a physical change because a physical change involves alteration in physical properties or appearance in color, sizes e.t.c but no new substances is formed. From the question, CoCl2 undergo a physical change because it's physical property which is color changed , its composition is not altered or no new substances is formed during the reaction.

It is a method of representing the 3- D structure of a molecule in which simple lines represent bonds in the plane of the image, wedge-shaped lines represent bonds towards the viewer and dashed lines represent bonds away from the viewer.

What are stereoisomers?

What is nucleophilic attack?

A nucleophilic attack occurs when an electron-rich species (the nucleophile) attack an electron-deficient species (the electrophile, a carbocation) forming a new bond between the nucleophile and the carbocation

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The gas which would be most suitable for the product is Helium.

A gas is the third state of matter in which there is little intermolecular bonding between the molecules of the substance. Gases usually occupy their container and usually have low boiling point

So, the gas which would be most suitable for the product is Helium.

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Answer:Sublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water.

Explanation:

letter B

Explanation:

An entire, intact organism may be

preserved in amber and ice

The oxidation number of Na in the compound Na2CO3 is +1.

To determine the oxidation number of Na in Na2CO3, we need to consider the known oxidation numbers of other elements and the overall charge of the compound.

1. The compound Na2CO3 contains two Na atoms and one C atom, along with three O atoms.

2. Oxygen (O) typically has an oxidation number of -2, unless it is in a peroxide where it is -1.

3. Carbon (C) is more electronegative than hydrogen (H) but less electronegative than oxygen (O), so it usually has an oxidation number of +4 in compounds.

4. The compound Na2CO3 has a neutral charge, which means the sum of the oxidation numbers of all the elements must be zero.

5. Let's assign the oxidation number of Na as x. Since there are two Na atoms, the total oxidation number contribution from Na is 2x.

6. The oxidation number of C in CO3 is +4, and the oxidation number of O is -2. Since there are three O atoms in CO3, the total oxidation number contribution from O is 3*(-2) = -6.

7. Setting up the equation: 2x + 4 + (-6) = 0.

8. Solving the equation: 2x - 2 = 0, 2x = 2, x = 1.

Therefore, the oxidation number of Na in Na2CO3 is +1.

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