What type of a reaction occurs when potassium metal reacts with fluorine gas?

PbCl2 would not dissolve because it is insoluble based on the solubility rules for substances that will dissolve in water. This compound would instead form a solid precipitate at the bottom of the container.

PbCl2 dissolves in water as it dissociates into Pb²+ and Cl¯ ions which attract polar water molecules. Just like potassium chloride, lead(II) chloride dissolves due to hydration of ions. Solubility of PbCl2 may increase with temperature.

When PbCl2 is dissolved in water, it dissociates into ions Pb²+ and Cl¯. These ions interact with water molecules due to the presence of polar bonds in water. Just like potassium chloride (KCl) dissolves in water by getting hydrated, or attracting water molecules, lead(II) chloride (PbCl2) dissolves in a similar fashion. Water, being a polar molecule, is attracted by the charges on both lead(II) and chloride ions. This hydration of ions is an important factor in the dissolution of many solids into liquids.

Moreover, the solubility of various solids in water tends to increase with temperature. Hence, if the PbCl2 was added to warm water, it might have increased its solubility, enabling more of PbCl2 to dissolve.

However, it is important to note that certain compounds like PbCl2 have relatively low solubility in water, and may still leave some solid undissolved even after thoroughly mixing.

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Answer: pH scale

Explanation:

Answer:

b. The shorter the half-life, the more dangerous the radioisotope.

The shorter the half-life, the more dangerous the radioisotope. Therefore, the correct option is option B.

The half-life is the length of time required for a single quantity (of substance) to drop to half its initial value (symbol t12). The phrase is widely used in nuclear physics to describe how quickly unstable atoms dissolve radioactively or how long stable atoms endure.

The term is often used more generally to indicate any type involving exponentially decaying. In the medical sciences, for example, the biological ½ of drugs and other chemicals in the human body is a word. Half-opposite life's in exponential growth is time's doubling. The shorter the half-life, the more dangerous the radioisotope.

Therefore, the correct option is option B

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Answer:

\boxed{\text{True}}

Explanation:

Consider the electrolysis of molten MgCl₂.

During electrolysis

[tex]\rm Reduction: Mg^{2+} + 2e^{-} \longrightarrow Mg\\Oxidation: 2Cl^{-} \longrightarrow Cl_{2} + 2e^{-}\\Overall: MgCl_{2} \longrightarrow Mg + Cl_{2}\\\\\text{Electrolysis is a }\boxed{\textbf{redox reaction}}[/tex]

Answer:

B

Explanation:

In an electrochemical cell in which the oxidation reaction is nonspontaneous  the oxidation will not occur spontaneously at the anode and the reduction will not be spontaneous at the cathode.  And according to the law for the calculation of the voltage potential of the electrochemical cell (Ecell):

Ecell = Eox. - Ere.  where (Eox. is the potential of the oxidation at the anode and Ere. is the potential of the reduction at the cathode). The standard potential for an electrolytic cell is negative, because of the Ere. which is greater than Eox.

The answer is : less than zero.

Answer:

Oxygen is the oxidizing agent and accept electrons

Explanation:

Answer:

Electrolytes are chemicals that break into ions (ionize) when they are dissolved in water. The positively-charged ions are called cations, while the negatively charged ions are called anions.  

Strong electrolytes completely ionize in water. This means 100% of the dissolved chemical breaks into cations and anions.

Weak electrolytes partially ionize in water. Pretty much any dissociation into ions between 0% and 100% makes a chemical a weak electrolyte, but in practice, around 1% to 10% of a weak electrolyte breaks into ions.

If a substance doesn’t ionize in water at all, it’s a nonelectrolyte.

Explanation:

The substance that serves as a good electrolyte in the list is the substance labelled Y.

An electrolyte is a solution that conducts electricity by the movement of ions in the solution. The high concentration of ions in the electrolyte implies that it has a good conductivity

Hence, the substance that serves as a good electrolyte in the list is the substance labelled Y.

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Answer:

It's a.

Explanation:

That would be Ca2+ , F- . We see in the compound CaF2 the  signs balance to give a neutral compound, 2+ balances with 2-.

Answer:  a. [tex]Ca^{2+}[/tex], [tex]F^-[/tex], [tex]CaF_2[/tex]

Explanation:

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.

(a) calcium and fluorine: Here calcium is having an oxidation state of +2 called as [tex]Ca^{2+}[/tex] cation and fluorine [tex]F^{-}[/tex] is an anion with oxidation state of -1. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]CaF_2[/tex]. called as calcium fluoride.

(b) sodium and chlorine: Here sodium is having an oxidation state of +1 called as [tex]Na^{+}[/tex] cation and chlorine [tex]Cl^{-}[/tex] is an anion with oxidation state of -1. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]NaCl[/tex] called as sodium chloride.

(c) barium and oxygen : Here barium is having an oxidation state of +2 called as [tex]Ba^{2+}[/tex] cation and oxygen [tex]O^{2-}[/tex] is an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]BaO[/tex] called as barium oxide.

(d) lead and oxygen : Here lead is having an oxidation state of +4 called as [tex]Pb^{4+}[/tex] cation and oxygen [tex]O^{2-}[/tex] is an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral [tex]PbO_2[/tex] called as lead(IV) oxide.

Answer:

A₃B.

Explanation:

3 AA + BB → 2 products.

3AA + BB → 2A₃B.

Answer:

=  66.33 kCal

Explanation:

The combustion of methane is given by the equation;

CH4(g) + 2O2(g) → CO2(g) + 2H2O(l); ΔH = -890.3 kJ/mol

The molar enthalpy of combustion of methane is -890.3 kJ/mol

This means 1 mole of CH4 yields 890.3 kJ/Mol

But, molar mass of methane is 16.04 g/mol

Therefore;

Heat produced by 5.0 g of methane will be;

= (5.0 g/ 16.04 g/mol)× 890.3 kJ/mol

= 277.525 kJ/mol

But; 1 kcal = 4.184 kJ

thus; = 277.525 /4.184

         =  66.33 kCal

Final answer:

To determine the amount of heat produced when 5.00 g of methane reacts with oxygen, convert the given heat production for 2.50 g of methane to kcal, find the heat value per gram, and then multiply by the mass of methane used (5.00 g).

Explanation:

The question asks how many kilocalories are produced when 5.00g of methane (CH₄) is reacted with oxygen (O₂) to produce carbon dioxide (CO₂) and water (H₂O) and release heat. To find this, we can use the information provided: the combustion of 2.50 g of methane produces 125 kJ of heat. As 1 kcal is equivalent to 4.184 kJ, we can first convert 125 kJ of heat to kcal, which gives us 29.8 kcal (125 kJ / 4.184 kJ/kcal).

Since this amount of heat is produced by 2.50 g of methane, we can find the heat produced by 1 g by dividing 29.8 kcal by 2.5, which gives us 11.92 kcal/g. For 5.00g of methane, the heat produced would be 5 times 11.92 kcal/g, equating to 59.6 kcal.

Answer:

Explanation:

It is precisely the repeating pattern of the valence electrons which is the responsible for the repeating pattern of the chemical properties: elements on a same group (column) of the periodic table have similar chemical properties because they have the same number of valence electrons.

The chemical changes (reactions) are the result of the interaction of the electrons of the elements, and, since the valence electrons are the outer most electrons, you can expect that it is the valence electrons which most influence the occurrence of the chemical reactions, which is what defines the chemical properties.

Here you have the pattern of the valence electrons shown by the representative elements on the periodic table:

Group number                  number of valence electrons

(column number)

           1                               1

           2                              2

          13                              3 (the ones digit of the column number)

          14                              4 (the ones digit of the column number)

          15                              5 (the ones digit of the column number)

          16                              6 (the ones digit of the column number)

          17                              7 (the ones digit of the column number)

          18                              8 (the ones digit of the column number)

Answer:

ultraviolet light is the shortest wavelength

Explanation:

Answer:

The correct answer is the first option: Ultraviolet light.

Explanation:

Hello!

Let's solve this!

The ultraviolet light is the one with the shortest wavelength. It is between visible light and x-rays. The place where this is seen is in the electromagnetic spectrum, which is the set of all electromagnetic waves.

Therefore, we conclude that the correct answer is the first option: Ultraviolet light.

The answer is Saturated

The solute is saturated when it can no longer absorb any more of a substance.

The answer is: the presence of free-flowing ions. Explanation: ionic compounds dissociate in water forming a solution with free ions.

Answer:

Oxidation reaction

Explanation:

When flame comes in contact with gasoline in the presence of oxygen, combustion takes place. Oxidation reaction involves reacting oxygen with a compound. To stop fire, we can stop the oxidation process by adding carbon (iv) oxide since it does not support combustion. Hence the reason why CO2 is used to stop flames.

Answer:

A

Explanation:

Answer: Option (D) is the correct answer.

Explanation:

It is known that in a closed system there will no exchange of heat or matter from the system to the surrounding. Whereas in an open system there will be exchange of both heat and energy from the system to the surrounding and vice versa.

Therefore, in the given situation cup A is a closed system and cup B is an open system. Hence, there will be no exchange of heat or matter from cup A to system and surrounding. So, it will cool slowly that cup B.

Thus, we can conclude that the statement no molecules will be able to evaporate at the surface of cup A, best explains why cup A will cool more slowly than cup B.

Answer:

12.6.

Explanation:

no. of millimoles of KOH = (MV)KOH = (0.183 M)(45.0 mL) = 8.235 mmol.

no. of millimoles of HCl = (MV)HCl = (0.145 M)(35.0 mL) = 5.075 mmol.

So,

[OH⁻] = [(no. of millimoles of KOH) - (no. of millimoles of HCl)] / (V total) = (8.235 mmol - 5.075 mmol) / (80.0 mL) = 0.395 M.

∵ pOH = -log[OH⁻]

∴ pOH = -log(0.395 M) = 1.4.

∵ pH + pOH = 14.

∴ pH = 14 - pOH = 14 - 1.4 = 12.6.

12.6 is the pH of a solution prepared by mixing 45.0 ml of 0.183 m KOH and 35.0 ml of 0.145 m HCl.

pH of the solution can be calculated as pH = 14 - pOH.

First of all we have to calculate the concentration of OH⁻ ions as follow:

Total volume of the solution = 45ml + 35ml = 80ml

Concentration of OH⁻ in terms of mole is calculated as:

[OH⁻]=(no. of millimoles of KOH - no. of millimoles of HCl)/Total volume

Given that, concentration of KOH = 0.183m

Volume of KOH = 45ml

Concentration of HCl = 0.145m

Volume of HCl = 35ml

Millimoles can be calculated as:

millimoles = concentration × volume

No. of millimoles of KOH = 0.183 M × 45.0 mL = 8.235 mmol

No. of millimoles of HCl = 0.145 M ×35.0 mL = 5.075 mmol

Now, [OH⁻] = 8.235 mmol - 5.075 mmol / 80.0 mL = 0.395 M

pOH = -log[OH⁻]

pOH = -log(0.395)

pOH = 1.4

Therefore, pH = 14 - 1.4 = 12.6

Hence, 12.6 is the pH of the solution.

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I believe is B if not then it's A

Answer:

Option (B)

Explanation:

R-12 is known as the Dichloro-difluoro-methane and it is a colorless gas. It is was earlier used in the refrigerators, vehicles air conditioning, and aerosol spray. The use of this R-12 was found to be depleting the ozone layer which was not a positive effect on the earth. Due to this, the use of this gas was banned and alternative energy resources were used. Its products containing this R-12 gas were not expensive and they were stable enough.

Hence, the correct answer is option (B).

Answer:

Explanation:

        Typical examples of physical properties are: mass, volume, density, boiling point, melting point, hardness, specific heat.

        Typical examples of chemical properties are reactivity with oxygen, reactivity with water, and any reactitivy in general.

Hence, applying those definitions to the set of choices you get:

A. Density, luster, boiling point (incorrect)

All of them are physical properties since they are observable and measurable without altering the composition of the sample.

B. Melting point, hardness, conductivity (incorrect)

They all are also physical properties. For example, melting point can be measured with a thermometer during the phase change.

C. Malleability, ductility, texture (incorrect)

Again, all physical properties. Ducitlity, for example, is the ability of the metals to form this wires.

D. Combustibility, flammability, reactivity (correct answer)

       All these properties can only be measured by producing the correspondant chemical reaction (change), so they are chemical properties.

Answer:

The correct option is D

Explanation:

Answer:

Organic compound is the correct answer

Explanation:

Answer:

Because the individual components of any mixture are not bonded to each other, the composition of those components can vary. Also, some of the physical properties of the individual components are still noticeable.

Explanation:

A mixture is a combination of two or more pure substances that are present in any proportion and each pure substance keeps its own physical and chemical properties.

As oppossite to mixtures, the compounds are pure substances formed by two or more different elements which are chemically bonded to each other. So, while in the compounds the components (elements) are bonded in a fixed proportion, and their composition cannot vary, in the mixtures each component may be present in any proportion, which means that the composition can vary.

Take, for example, the simple case of talc and iron particles.This is a mixture. Talc is not bonded to the iron particles, and so their proportion, the compositoin, can vary in any form. Aslo, both talc and iron particles keep their own physical properties: you can perfectly separate the mixture by using a magnet to attract the iron particles, because they have not lost their magnetic property (a physical one).

Answer:

Explanation:

The total energy required to convert 1 mole of liquid from 5°C below its boiling point to 1 mole of gaseous Ar at 5° above its boiling point may be calcualted in three stages:

1) Energy to heat the liquid Ar from 5°C below its boling point to the boiling point:

2) Energy to vaporize the liquid Ar:

3) Energy to heat the gaseous Ar 5°C above its boiling point:

4) Total energy (E)

The total energy required to convert 1 mole of liquid Argon from 5°C below its boiling point to 1 mole of gaseous Ar at 5°C above its boiling point is calculated through a multi-step process. The steps involve increasing the temperature of the liquid to its boiling point, vaporizing at the boiling point, and further heating the gas above the boiling point. The sum of these three steps yields a total required energy of 6735 J.

This is a multi-step thermodynamics problem in chemistry that requires the use of specific heat, change in temperature, and enthalpy of vaporization. The energy required to convert 1 mole of liquid Argon from 5°C below its boiling point to 1 mole of gaseous Ar at 5°C above its boiling point can be found through the equation: q = m*c*ΔT, where q is the heat energy, m is the amount of Argon in moles, c is the specific heat, and ΔT is the change in temperature.

First, we need to raise the temperature of the liquid argon from 5°C below the boiling point to the boiling point. Using the specific heat for liquid argon, this gives us q1 = (1 mol)(25.0 J/mol·°C)(5°C) = 125 J.

Next, we have to provide the heat of vaporization to convert the liquid to gas at the boiling point, which gives us q2 = 6506 J/mol. Then we have to further heat the gas from the boiling point to 5°C above it. Using the specific heat for gaseous argon, this gives us q3 = (1 mol)(20.8 J/mol·°C)(5°C) = 104 J.

Adding these three energy amounts together, we find that total energy required is q_tot = q1 + q2 + q3 = 125 J + 6506 J + 104 J = 6735 J.

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Answer:

Explanation:

According to Avogadro's principle, equal volume of gases at the same temperature and pressure will contain the same number of particles (atoms or molecules).

Therefore, being the three flasks identical, which includes that they have the same volumen, and being that they contain different gases at standard temperature and pressure, regardless of the chemical formula of each gas, by direct use of Avogadro's principle, they all will contain the same number of molecules.

The ideal gas equation, pV = nRT reflects this fact: if you isolate the ratio V/n, you get V/n = RT/p. Then, since RT/p (the right side) is constant, V/n is also constant, meaning that for a fixed volume the number of particles is constant, regardelss of the gas.

According to Avogadro's law, equal volumes of gas at the same temperature and pressure contain the same number of molecules. Therefore, all three flasks, despite containing different gases, would have the same number of molecules.

The subject of your question pertains to the principles of chemistry, specifically related to Avogadro's law. According to Avogadro's law, equal volumes of different gases at the same temperature and pressure contain an equal number of molecules. Therefore, Flasks A, B, and C which contain C2H6, O3, and NH3 respectively, all at standard temperature and pressure, would each contain the same number of molecules. This principle applies regardless of the identity of the gas, as it is related to the behaviour of gases as outlined in the ideal gas law.

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The statement provided is false; the basic structural unit of a compound is the molecule, not the atom. Molecules consist of atoms from different elements bonded in fixed ratios, forming the substance known as a compound.

The statement 'For compounds, the basic structural unit representing the compound is the atom.' is false. The smallest particle of most compounds is called a molecule. For instance, a water molecule (H₂O) is always made up of one atom of oxygen and two atoms of hydrogen. This molecule is the basic unit that represents the compound water, not a single atom. Compounds are characterized by atoms of different elements bonded together, and these atoms are in fixed, whole-number ratios.

Isomers are molecules that have the same number and type of atoms but arranged differently. For example, molecules with the formulas CH₃CH₂COOH and C₃H₆O₂ could indeed be structural isomers since they have the same molecular formula but could have a different arrangement of the atoms within the molecule.

Most elements exist as individual atoms as their basic unit. When combined in specific ways, these atoms form molecules, which are the basic units of compounds. A single atom by itself cannot represent a compound; it is the molecule, composed of two or more atoms, that does so.

Answer:

134g/mol

Explanation:

Answer:

8.0 M.

Explanation:

∴ (MV) of KNO₃ before dilution = (MV) of KNO₃ before dilution.

M = 12.0 M, V = 500.0 mL.

M = ??? M, V = 500.0 mL + 250.0 mL = 750.0 mL.

∴ M after dilution = (MV) before dilution / (V) after dilution = (12.0 M)(500.0 mL)/(750.0 mL) = 8.0 M.

By increasing the molecular vibrations

Answer:

14.77 mol.

Explanation:

Using cross multiplication:

1.0 mole of He contains → 6.022 x 10²³ atoms.

??? mole of He contains → 8.84 x 10²⁴ atoms.

∴ The no. of moles of He contains (8.84 x 10²⁴ atoms) = (1.0 mol)(8.84 x 10²⁴ atoms)/(6.022 x 10²³ atoms) = 14.77 mol.

Answer:

[tex]\boxed{\text{10.7 ng}}[/tex]

Explanation:

Let A₀ = the original amount of ⁵⁵Co .

The amount remaining after one half-life is ½A₀.

After two half-lives, the amount remaining is ½ ×½A₀ = (½)²A₀.

After three half-lives, the amount remaining is ½ ×(½)²A₀ = (½)³A₀.

The general formula for the amount remaining is:

A =A₀(½)ⁿ

where n is the number of half-lives

n = t/t_½

Data:

   A = 1.90 ng

    t = 45 h

t_½ = 18.0 h

Calculation:

(a) Calculate n

n = 45/18.0 = 2.5

(b) Calculate A

1.90 = A₀ × (½)^2.5

1.90 = A₀ × 0.178

A₀ = 1.90/0.178 = 10.7 ng

The original mass of ⁵⁵Co was [tex]\boxed{\text{10.7 ng}}[/tex].