What are the [H₃O⁺] and the pH of a buffer that consists of 0.20 M HF and 0.25 M KF (Kₐ of HF = 6.8X10⁻⁴)?

The energy that an object gains or loses is related by the equation (Q = m•C•T). since a positive value means that heat was added to the system. The heat can be gained or lost without change in temperature.

by the equation (Q = m•C•T)

m=3.50g

C=35

T=+5°c

Q=3.50*35*(+5oC)=612.5.

An object's heat uptake or loss and the resulting temperature variations are related by the description above and the following equation (Q = m•C•T). We now know that heat can occasionally be gained or lost without a corresponding change in temperature. When the substance is changing states, this is what happens.

the amount of heat needed to raise a substance's temperature by one degree Celsius or one kelvin per unit mass.It has the symbol c. joule per kg kelvin is the SI unit. In the SI system, all types of energy are measured in (J/kg K)joules. Because heat is a form of energy, the SI unit for heat is also joules (J), and it is defined as the quantity of energy required to increase the temperature of a given mass by one degree. This is significant because heat is a form of energy.

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The rust is not formed in test tube 1 since the Gibbs free energy of the products is higher without water being present. Hence, the justified option is C.

The Gibbs free energy of the product is greater when water is present. The given chemical reaction can be represented as:

                         4 Fe(s) + 3O₂(g) → 2Fe₂2O₃(s)

                          ΔG°rxn = -1800 kJ/mol

As the reaction is spontaneous (ΔG°rxn is negative), the reaction proceeds with a release of energy. This implies that the formation of rust in the second test tube shows that the reaction is thermodynamically favored. The student's observation demonstrates that the presence of water has accelerated the reaction, which is consistent with the proposed reaction mechanism in which water is required for oxygen to diffuse to the iron surface.

Gibbs free energy is the difference between the energy of the products and the reactants, so a negative Gibbs free energy indicates that the energy of the products is less than the energy of the reactants. As a result, if water is not present, the Gibbs free energy of the products would be greater than when water is present.

Therefore, the rust is not formed in test tube 1 since the Gibbs free energy of the products is higher without water being present. Hence, the justified option is C. The product is not formed in measurable quantities because the equilibrium constant for the reaction when water is not present is less than one.

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The time needed to go from the original number of atoms to one-half of that number is the same as the time needed to go from one-half of the number of atoms to one-quarter of the number.

This is because the rate of radioactive decay is constant, meaning that the same amount of time is required for each successive halving. The time required to get from the original number of atoms to half that number is the same as the time required to go from half the original number of atoms to quarter of that number. The duration it takes for half of an element's parent isotopes to transform into daughter isotopes is known as its half life. While only one electron is lost during beta decay, the nucleus loses two protons and two neutrons during alpha decay. Radiation decay occurs exponentially.

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Answer:

coal

Explanation:

combustion reaction convert chemical energy into light and heat

Answer:

When we dissolve sugar in water,the particles of sugar get into the spaces between the particles of water which is known as the intermolecular spaces.

The sugar particles are dissolved in the water and form a homogeneous solution.

This indicates that the sugar particles are in the space between water molecules.

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During the electrolysis of an aqueous solution of NaBr, water is also present in the solution along with NaBr.

Therefore, the products formed at the electrodes depend on the reduction and oxidation potentials of both the ions present in the solution as well as water.At the cathode (negative electrode), water can be reduced to hydrogen gas (H2) or sodium ions (Na+) can be reduced to sodium metal, depending on their reduction potentials. In this case, the reduction potential of water (-0.83 V) is less than that of Na+ ions (-2.71 V), so water is reduced to hydrogen gas 2H2O + 2e- → H2 + 2OH-At the anode (positive electrode), the Br- ions present in the solution can be oxidized to form Br2 molecules or water can be oxidized to form oxygen gas (O2) and hydrogen ions (H+), depending on their oxidation potentials. In this case, the oxidation potential of Br- (-1.07 V) is greater than that of water (-1.23 V), so Br- ions are oxidized to form Br2 molecules:

2Br- → Br2 + 2e-Therefore, the final products of the electrolysis of NaBr solution are hydrogen gas (H2) at the cathode and bromine gas (Br2) at the anode.

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Answer:

a. Plum pudding model

Explanation:

The plum pudding model of the atom was proposed by J.J. Thomson. It was the model he derived from his experiment on the gas discharge tube.

J.J Thomson was the first person to discover electrons which he called cathode rays because in the discharge tube, they emanate from the cathode.

Answer:

The number of nitrogen molecules inside of berylluim nitrite are 5 cells.

Explanation:

The element/ion that is the easiest to reduce can be determined by referring to the given activity series. Among the options the element/ion  is the easiest to reduce is H₂ (g) to 2H⁺ (aq) + 2e⁻. Option C is correct.

The activity series represents the relative ease with which elements or ions can be oxidation or reduced. In the given activity series, H2 (g) is listed before Sn (s), Pb (s), and Cu (s), indicating that it is more easily reduced than these elements. When H₂ gas is reduced, it loses electrons to form 2H⁺ ions, and the electrons released in the reduction process are represented by 2e⁻. This indicates that H₂ has a higher tendency to undergo reduction compared to the other elements listed.

Therefore, based on the provided activity series, H₂ is the easiest to reduce among the given options.

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Answer:

See explanation

Explanation:

According to the law of conservation of energy; energy is neither created nor destroyed but is converted from one form to another.

This means that energy can not be lost, we can trace the transfer of energy between a system and its surroundings.

When a pot of water at 25°C is placed over a flame until it has boiled away, energy is transferred from the pot (the system) to the surroundings hence the temperature of the surroundings rises accordingly.

The pH of a 0.150 M piperidine solution (C5H10NH) with a Kb of 1.3x10^-3 is 11.72. This indicates that the solution is basic.

To calculate the pH of a 0.150 M piperidine (C5H10NH) solution with Kb = 1.3 x 10^-3, we'll first determine the pOH and then find the pH. Piperidine is a weak base and will undergo an equilibrium reaction with water:
C5H10NH + H2O ↔ C5H10NH2+ + OH-
We can use the Kb expression:
Kb = [C5H10NH2+][OH-] / [C5H10NH]
Since the initial concentration of piperidine is 0.150 M, we'll assume x mol/L of it reacts to form C5H10NH2+ and OH- ions. The equilibrium concentrations will be:
[C5H10NH] = 0.150 - x
[C5H10NH2+] = x
[OH-] = x
Now, substitute these values into the Kb expression:
1.3 x 10^-3 = (x)(x) / (0.150 - x)
Solve for x to find the concentration of OH- ions:
x ≈ 0.0053 M
Now, calculate the pOH:
pOH = -log10[OH-] = -log10(0.0053) ≈ 2.28
Finally, find the pH using the relationship:
pH + pOH = 14
pH = 14 - 2.28 ≈ 11.72
So, the pH of the 0.150 M piperidine solution is approximately 11.72.

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Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

\(volume = \frac{mass}{density} \\\)

From the question

mass = 83.7 g

density = 0.785 g/mL

We have

\(volume = \frac{83.7}{0.785} \\ = 106.62420\)

We have the final answer as

Hope this helps you

Answer:

The answer is A. It has the most comprehensive list of what is needed for a beaker reaction with high heat.

The list of lab equipment and tools is a complete list needed to heat a reaction in a beaker with high heat beaker, ring stand, iron ring, Bunsen burner, beaker tongs, and wire gauze. The correct option is a.

Lab equipments are those objects or instruments that are used in a science or other types of the lab. These equipments are used in many processes of a lab.

These equipments include many scientific instruments and beakers and measuring scales for calculating the chemicals and or results. A beaker is used to keep the chemicals and other items.

The ring stand is used to put open the burner to keep the beaker on it. Tongs are to hold a beaker, and gauze is a type of burner.

Thus, the correct option is a. beaker, ring stand, iron ring, Bunsen burner, beaker tongs, and wire gauze.

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Answer: a compound!

Explanation: a compound is something that contains two or more elements that are chemically combined in a fixed proportion!

After three half-lives, 12.5% of the original sample of polonium remains.

Polonium is a very infrequent natural element. It is found in uranium ores but it is careless to extract it. It is obtained by bombarding bismuth-209 with neutrons to give bismuth-210, which then purifies to form polonium. All the industrially produced polonium in the world is made in Russia.Po-210 is an effect of the radioactive decay of uranium-238, which decays to radon-222 and then to polonium. Polonium 210 has a half-life of 138 days. Let the opening value of polonium-218 be 100. First half-life. Therefore, 6.25 % of the original sample remains after 4 half-lives that are 12 minutes. Element Polonium has atomic Number 84, p-block, Mass number is 209.

So we can conclude that polonium is a radioactive, silvery-gray, or black metallic element of the oxygen group in the periodic table.

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Answer

1.25M

Explanation

to calculate the molality we use the following equation

Molality = moles of solute / Kg of solvent

step 1: to find the moles of glucose we divide the mass by the Molar mass of glucose

moles = mass (g)/ Molar mass (g/mol)

= 18.0 g / 180,156 g/mol

= 0.0999 moles of glucose

now that we have moles of glucose, the next step is to convert 80.0g of water to Kg of water

1 kg = 1000g

Kg of water = 80g/1000g /kg

= 0.08Kg

Molality = 0.0999 mols / 0.08 kg

= 1.25M

The Maxwell distribution of velocities describes the distribution of speeds of gas molecules at a given temperature. It is based on the kinetic theory of gases and provides insights into the behavior of gas molecules.

As the molecular mass of a gas increases, several characteristics of the Maxwell distribution change. Firstly, the spread of speeds widens. This means that the range of velocities observed for heavier gases becomes broader compared to lighter gases. In other words, the distribution of speeds becomes more spread out Secondly, fewer molecules have speeds close to their average speed. The average speed of gas molecules is determined by the temperature, but as the molecular mass increases, the likelihood of individual molecules having speeds very close to the average decreases. This suggests that there is a greater dispersion or variation in the speeds of molecules in heavier gases. Lastly, as the molecular mass increases, a higher proportion of molecules have very high speeds. This means that heavier gas molecules are more likely to exhibit velocities that are significantly higher than the average speed. This trend can be attributed to the increased mass of the molecules, which affects their kinetic energy and consequently their speeds.

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The phenomenon observed by the student exploring magnets and a bag of other objects can be explained with the property of magnetism known as magnetization.

Magnetization occurs when a magnetic field induces the alignment of the magnetic moments of a material in the direction of the applied magnetic field. This property allows magnets to attract ferromagnetic materials such as iron, nickel, and cobalt.The nail, paper clip, and screw in the experiment are all made of ferromagnetic materials. When the nail is touched to a magnet, it becomes magnetized, meaning that its magnetic domains align in the direction of the magnetic field produced by the magnet. As a result, the magnetized nail now has a magnetic field that can attract the paper clip, which in turn becomes magnetized by being in contact with the nail. This magnetization allows the paper clip to attract the screw, which becomes magnetized in turn.The transfer of magnetization from one object to another is known as magnetic induction, which explains why the paper clip can pick up the screw even though it is not in direct contact with the magnet.

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If a sample of oxygen occupies a volume of 2.15 L at a pressure of 58.0 kPa and a temperature of 25°C, 1.13L is the volume occupied at 101.3 kPa and 0°C.

A measurement of three-dimensional space is volume. It is frequently expressed quantitatively using SI-derived units, such the cubic metre or litre, or different imperial or US-standard units, including the gallon, quart and cubic inch. Volume and length (cubed) have a symbiotic relationship. The volume much a container is often thought of as its capacity, not as the amount of space it takes up. In other words, the volume is the amounts of fluid (liquid or gas) that the container may hold.

P1×V1/T1 =P2×V2/T2

58.0×2.15/ 298 =101.3×V2/ 273

Volume =1.13L

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Materials generally become warmer when they are "absorbed" by light, this statement is more detailed. So, the correct answer is "absorbed by them."

Explanation: When a material absorbs light, it receives energy from the light, which leads to an increase in temperature. When light is absorbed by a material, the energy of the light is transformed into internal energy in the material. The temperature of a material can increase as a result of this energy absorption.

This is due to the fact that the increased internal energy of the molecules in the material causes them to vibrate more quickly and hence results in a temperature rise.

The light reflects or transmits when it passes through the material. When light reflects off a surface, it bounces back in the opposite direction. Transmitted light travels through a material without being absorbed by it.

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Answer:

The study of reaction "Rates" is called Chemical "Kinetics.

Answer:

b. A hydrogen sulfide molecule has lone pairs of electrons

Explanation:

The presence of lone pairs indictates that the molecule will be polar unless its molecular geometry is linear or square planar. In the case of H2S, its shape is bent due to the lone pair and it is a slightly polar molecule.

Answer:

Period 2

Explanation:

From the picture provided, I am guessing this is Fluorine. Normal Fluorine has 9 protons, electrons, and atomic number. Thus, it can be found in the second period.

***Period # = # of electron shells

Answer:

43 g N₂

Explanation:

To find the mass of N₂ required, you need to (1) convert grams H₂ to moles H₂ (via molar mass), then (2) convert moles H₂ to moles N₂ (via mole-to-mole ratio from equation coefficients), and then (3) convert moles N₂ to grams N₂ (via molar mass). It is important to arrange the conversions in a way that allows for the cancellation of units. The final answer should have 2 sig figs to match the amount of sig figs of the given value.

Molar Mass (H₂): 2(1.008 g/mol)

Molar Mass (H₂): 2.016 g/mol

Molar Mass (N₂): 2(14.009 g/mol)

Molar Mass (N₂): 28.018 g/mol

1 N₂(g) + 3 H₂(g) -----> 2 NH₃(g)

9.3 g H₂           1 mole             1 mole N₂             28.018 g
--------------  x  ----------------  x  --------------------  x  ------------------  =  43 g N₂
                        2.016 g            3 moles H₂            1 mole

When antacid reacts with HCl to produce H2CO3 it produce fizzy gas react due to a double displacement reaction.

Table salt and carbonic acid are produced in a two fold displacement process when hydrochloric acid and antacid are combined. Additionally, due to the instability of carbonic acid, it will decompose into water and carbon dioxide, emitting a "fizzy" gas.

Strong acid hydrochloric acid is denoted by the chemical formula HCl. The primary ingredient in antacids is sodium bicarbonate, sometimes known as baking soda and has the chemical formula NaHCO3.

Antacid undergoes a chemical reaction when it reacts as a carbonate with powerful acids like hydrochloric acid to create compounds with a different chemical makeup from the beginning components. Similar reactions will be produced by other carbonates, such as calcium carbonate, which makes up the majority of Tums.

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Answer:

0.075 moles n=m/M so divide the mass (m) by the molar mass (M) to get the n which is the number of moles

Explanation:

Answer:

where ni = no. of moles of any compound and mi = molecular mass of any ... Sulphur : (w) O.C. + HNO3 → H2SO4 + BaCl2 → (w1) BaSO4 ... 0.365 g of pure HCl gas is dissolved in 50 mL of solution. ... yield is 80% then calculate the amount of Cl2 produced. the amount of water ... Fe2O3 + 3SO3 Fe2(SO4)3

Explanation:

did that help if not please contact me in the comments.

Answer:

31.99 g O2

Explanation:

Any gas at STP has a molar volume of 22.4 L/mol. This may be an amount you want to memorize.

(given volume) * (molar volume)= moles of O2

\(22.4 L * \frac{1 mol}{22.4 L}= 1 mol O2\)

Now we can convert moles of O2 to grams using the molar mass of O2.

(moles of O2) * (molar mass of O2)= grams of O2

\(1 mol * \frac{31.99 g}{1 mol} = 31.99g\)

The statement of the mass of O2 is "31.99 g."

A substance is something to do with mass that takes up space. The mass of a compound is the total amount of atoms present in grams that make up a molecule. The grams is the unit of mass

While the preceding method may have been utilised, PV = nRT is not required when the system is at STP. Simply put, 1 mole of an ideal gas equals 22.4 litres at STP.

Number of moles in 22.4 L of O2 at STP,

= (given volume) * (molar volume)

\(=\;22.4\;L*\frac{1\;mol}{22.4\;L}\)

= 1 mol O2

Now, mass of O2 at STP comes out to be,

= (moles of O2) * (molar mass of O2)

\(=\;1\;mol\;O2\;*\frac{31.99\;g}{1\; mol\;O2}\)

= 31.99 g

Hence the correct answer is 31.99 g.

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Answer:  1. F

2. F

3. T

4. F

5. T

6. T

Explanation:

I am not sure i'm sorry if it isn't right