in order to protect aquifers near landfills, material is placed under the soil to prevent pollution. which following property must the protective material possess?
a) high porosity
b) low permeability
c) high reflectivity
d) low conductivity

The ionic equation, [tex]Cu_{2}[/tex]+(aq) + Zn(s) → Cu(s) + [tex]Zn_{2}[/tex]+(aq), represents a spontaneous reaction in a voltaic cell where Zinc is oxidized (loses electrons) and Copper is reduced (gains electrons). This occurs because Zinc is more reactive than Copper.

In a voltaic or galvanic cell, oxidation occurs at the anode and reduction occurs at the cathode. The reaction is spontaneous, which means it can occur without any external energy. Considering your given ionic equations, 3. [tex]Cu_{2}[/tex]+(aq) + Zn(s) → Cu(s) + [tex]Zn_{2}[/tex]+(aq) best represents a spontaneous reaction that would occur in a voltaic cell. This is because zinc is more active than copper and donates electrons (becomes oxidized) spontaneously. The zinc becomes zinc ions ([tex]Zn_{2}[/tex]+(aq)) and copper ions ([tex]Cu_{2}[/tex]+(aq)) gain the electrons and reduce to copper (Cu(s)). The redox potential of the [tex]Cu_{2}[/tex]+/Cu redox couple is lower than that of the [tex]Zn_{2}[/tex]+/Zn, making the reaction spontaneous in forward direction.

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Answer:

5.4 M.

Explanation:

(MV)acid = (MV)NaOH

M of acid = ??? M, V of acid = 35.0 mL.

M of NaOH = 3.0 M, V of NaOH = 63.0 mL.

∴ M of acid = (MV)NaOH / (V)acid = (3.0 M)(63.0 mL)/(35.0 mL) = 5.4 M.

Answer:

Explanation:

Elements in the same family belong to the same group.

A group on the periodic table is the vertical arrangement of elements. Elements in the same group have the same amount of valence electrons in their outermost shell. We know that the valency of an element dictates its chemical properties. In group I for example, elements here have just a valence electron, this makes group I elements readily lose their electrons to achieve a noble configuration.

Physical properties to an extent also varies and progresses down the group steadily.

This is why elements in the same family are said to generally have similar properties

Elements in the same family or group on the periodic table generally have similar properties, such as reactivity and the types of compounds they form, because they have the same number of valence electrons. For example, the halogens in Group 17 and the alkali metals in Group 1 have similar properties due to their shared valence electron configurations.

The elements in the same family or group on the periodic table generally have similar properties because they have the same number and distribution of electrons in their valence shells. These valence electrons determine how elements interact with other substances and react chemically. For example, elements in the same family tend to have similar reactivity and form similar types of compounds.

For instance, the halogens (fluorine, chlorine, bromine, iodine, and astatine) are all located in Group 17 of the periodic table and have similar properties because they all have seven valence electrons. They are highly reactive nonmetals that have a tendency to gain one electron to achieve a stable electron configuration.

Another example is the alkali metals (lithium, sodium, potassium, etc.), which are found in Group 1. They all have one valence electron and are highly reactive metals that readily lose this electron to form a +1 cation.

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Answer:

C

Explanation:

Answer:

D

Explanation:measurement of heat The usual means of measuring temperature is a thermometer. It measures the degree or intensity of heat and usually consists of a glass tube with a bulb at the lower portion of the tube that contains mercury, colored alcohol, or a volatile liquid.

Exothermic Reactions

Answer:

Reaction B is exothermic

Explanation:

From the context of thermodynamics, chemical reactions can be broadly classified as endothermic and exothermic reactions.

Endothermic reactions involve absorption of energy and show a positive value for the reaction enthalpy i.e. ΔH is positive. In contrast, exothermic reactions are accompanied by the release of energy and show a negative value for the enthalpy change i.e. ΔH is negative.

In a given chemical reaction energy is required to break bonds and it is released during the formation of new bonds.

The Reaction B is such that, the energy required to break bonds is less than energy released during formation bonds. Therefore, since there is a net release of energy, the reaction is exothermic.

Answer:

Explanation:

Because the alkali metal is really willing to give up its electron much more so than Hydrogen.

The redox reaction looks like this

K ===> K+   +    1 e-    The reduction vo is very high which means that the K really does want to give up that electron.

2H+  +2e- ====> H2  The oxidation vo is almost 0 but the Hydrogen is the perfect recipient for the 2 electrons.

Answer:

"CO(g) + 2H2 (g) <---> CH3OH (g) and that the reaction is exothermic (the delta H value is negative). The reaction is exothermic, so lowering the temperature will shift the equilibrium toward the right. Since the reaction uses 3 moles of gas to form 1 mole of gas, increasing the pressure will shift the reaction toward the right. So, low temperature and high pressure will produce the highest yield.

Answer:

The answer would be 2. carbon compounds.

Hope this helps!

Brainliest?

Answer:

[tex]\boxed{\text{2700 J}}[/tex]

Explanation:

HCl + NaOH ⟶ NaCl + H₂O

There are two energy flows in this reaction.  

Heat of reaction + heat to warm water = 0  

           q₁             +              q₂                 = 0  

           q₁             +          mCΔT              = 0  

Data:

    m(HCl) = 50 g

m(NaOH) = 50 g

           T₁ = 22       °C

          T₂ = 28.87 °C

           C = 4.18 J·°C⁻¹g⁻¹

Calculations:

 m = 50 + 50 = 100 g

ΔT = 28.87 – 22 = 6.9 °C

 q₂ = 100 × 4.18 × 6.9 = 2900 J

q₁ + 2900 = 0

q₁ = -2900 J

The negative sign tells us that the reaction produced heat.

The reaction produced [tex]\boxed{\textbf{2900 J}}[/tex].

The reaction between HCl and NaOH in the situation described produced 2.87 kJ of heat.

The question is asking how much heat is produced by the reaction between 1.00 M hydrochloric acid (HCl) and 1.00 M sodium hydroxide (NaOH) in a coffee cup calorimeter when the initial temperature is 22ºC and the final temperature is 28.87ºC. The heat released in a chemical reaction can be calculated from the formula q = mcΔT, where q is heat, m is mass, c is specific heat, and ΔT is the change in temperature. In this case, the mass of the solution is 100g (50g HCl + 50g NaOH), the specific heat of the solution is given as 4.18 J/gºC, and the change in temperature is 28.87ºC - 22ºC = 6.87ºC.

Applying the numbers in the formula we get:

q = 100g * 4.18 J/gºC * 6.87ºC = 2872.6 J

Since the question requires the answer in kJ, we divide the result by 1000: Q = 2.87 kJ. The reaction between HCl and NaOH in the calorimeter produced 2.87 kJ of heat.

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Answer:-

Name of Chemical Compound: (if given otherwise not necessary) Ethane.

Chemical formula: C2H6.

Finding molar mass of Ethane(C2H6):-

Molar mass of Ethane = 12×2+1×6

Molar mass of Ethane = 2 + 6

Molar mass of Ethane = 30 g/mol

[ Note:

• Molar mass: Mass(is represented/taken in grams)of one mole of a substance.

• g/mol means grams per mole ].

Answer:

Molar mass of ethane is determined by adding atomic mass of all the constituent atoms.

Explanation:

Molar mass of a molecule is determined by adding all the atomic masses of constituent atoms.

In ethane molecule, there are two carbon atoms and six hydrogen atoms.

Atomic mass of carbon is 12g and atomic mass of hydrogen is 1g.

So molar mass of ethane is- [tex](2\times atomic mass of C)+(6\times atomic mass of H)[/tex] or [tex](2\times 12g)+(6\times 1g)[/tex] or 30g.

Answer:

0.

Explanation:

[H⁺] = 1.0 M.

∵ pH = - log[H⁺]  

∴ pH = - log(1.0 M) = 0.

Final answer:

The pH of a 1.0 molar solution of HCl is 0.

Explanation:

The pH of a 1.0 molar solution of HCl can be calculated using the formula pH = -log[H3O+]. Since HCl is a strong acid, it completely ionizes in water to form H3O+ ions. Therefore, the hydrogen ion concentration is equal to the molar concentration of HCl.

Thus, the pH of a 1.0 molar solution of HCl would be -log(1.0) = 0.

Therefore, the pH of the solution is 0.

This question is hard but I found the answer from merit nation

Answer:

k and br is right answer

The  list of elements given where k and br are two elements that form the ionic compound.

The following information should be considered:

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Answer:

4) transferred from the valence shell of one atom to the valence shell of another atom

Explanation:

Electrons are located outside of the nucleus which contains the protons and the neutrons.

For bonds to form, valence electrons located in the outermost shell electrons are involved. These are the valence electrons. These outer shell electrons can be shared or transferred between two combining atoms to form stable atoms.

In ionic bonds, the electrons are transferred from one specie to another. The atom that loses the electrons becomes positively charged and the receiving atom becomes negatively charged. This is the crux of ionic bonds.

Answer:

Explanation:

Ionic bonds are formed by the electrostatic attraction between a positive ion (named cation) and a negative ion (named anion).

A cation is formed when an atom donates one or more electrons from its valence shell, while an anion is formed when an atom accepts one or more electrons.

The most classical example of a ionic bond is that of sodium chloride: sodium (Na) is a metal with one valence electron, and chlorine (Cl) is a nonmetal with 7 valence electrons. Then, sodium releases its valence electron (forming the cation Na⁺), which is accepted by chlorine (forming the anion chloride, Cl⁻). These two ions with opposite charge are bonded by the attractive electrostatic force.

Covalent bonds are the result of sharing valence  electrons. In this case, the atoms do not exchange (donate/accept) electrons but share them; meaning that the shared electrons belong to the outermost energy level of the two atoms, now bonded by the covalent bond.

Furthermore, the covalent bond may be polar or non-polar. A polar covalent bond is formed when the two atoms have different electronegativities, because in such case one atom pulls the electrons harder than the other, resulting in an uneven distribution of the charge, i.e. forming a dipole.

Answer:

Option C) 1,230 kJ

Explanation:

According to the data, 1 mol of propane liberates 2,220 kJ of energy when it is combusted. If we have 24.5 g of propane, this mass is equal to 0,56 mol (of propane):

44.097 g of propane---->1 mol

24.5 g of propane-------x= 0.56 mol

Then, the enthalpy of the described chemical reaction (propane´s combustion) is 2,220 kJ when 1 mol of propane is combusted, so:

1 mol propane---------->2,220 kJ of energy

0.56 mol propane (24.5 g)------------x= aproximately 1,24 kJ (which would be option C)

To calculate the enthalpy of combustion for 24.5g propane, divide the mass by the molecular weight to obtain the number of moles. Then, multiply the moles by the given enthalpy of reaction to find the enthalpy of combustion. The enthalpy of combustion for 24.5g propane is 1,230 kJ.

To calculate the enthalpy of combustion for 24.5g propane, we need to first convert the mass of propane to moles. Dividing the mass by the molecular weight of propane gives us 24.5 g / 44.097 g/mol = 0.5558 mol. Then, we can use the equation given to calculate the enthalpy of combustion:

Enthalpy of combustion = ΔHreaction * moles of propane

Plugging in the values, we get:
Enthalpy of combustion = 2,220 kJ/mol * 0.5558 mol = 1,230 kJ

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Answer:

2.2 J/°C.g.

Explanation:

Q = m.c.ΔT,

where, Q is the amount of heat released by the unknown substance (Q = 550 J).

m is the mass of the unknown mass (m = 25.0 g).

c is the specific heat of the unknown substance (c = ??? J/°C.g).

ΔT is the difference between the initial and final temperature (ΔT = 10°C).

∴ c = Q/(m.ΔT) = (550 J)/(25.0 g)(10°C) = 2.2 J/°C.g.

These are two questions and two complete answers.

Answers:

Explanation:

A) Question #5.

The figure shows that the parent nuclide is [tex]^{222}_{86}Ra[/tex] and the daughter nuclide is [tex]^{218}_{84}Po[/tex]

A mass number balance and an atomic number balance show the features of the radiation emitted.

a) Mass number balance:

The mass number is the superscript to the left of the chemical symbol and is the amount of protons and neutrons in the nucleus of the atom.

Hence, the mass number of the unknown emitted particle is 4.

b) Atomic number balance.

The atomic number is the subscript to the left of the chemical symbol and is the number of protons in the nucleus of the atom.

Hence, the atomic number (number of protons) of the unknown emitted particle is 2.

Conclusion: the emitted particle is a particle with 2 protons and 2 neutrons, which is a nucleus of helium, ⁴₂He, also called alpha particle, and the reaction is named alpha decay.

B) Question #6

Again, a mass number balance and an atomic number balance will tell which element is the missing product in the reaction.

The reaction is:

[tex]^{233}_{92}U+^1_0n{->}^{99}_{42}Mo+3^1_0n+?[/tex]

a) Atomic number balance:

Hence, the missing product has atomic number 50 which permits to tell that it is an atom of tin (Sn).

b) Mass number balance:

Which means that the missing product has a 132 neutrons and protons:

The symbol of this atom is:

Magnesium has a full outer shell because it says +2 for Mg, which means it loses 2 electrons. It leaves Mg with an outer shell of 8 electrons, which is a full valence shell.

Mg+2 among the following has the full outer shell , therefore option (d) is correct.

A full outer shell is known as the noble gas configuration where the outer shell of an atom is energetically stable and contains 8 outer electrons .

It belongs to a group called the noble gases. When the outer shell has the maximum number of electrons, the electron shells. are said to be full.

The inner shells of an atom are always full. If the outer shell of an atom has less than , its maximum number of electrons then it will not be stable.

Elements with complete outer shell are Helium , Neon, Argon, Krypton , Xenon , Radon .

Mg+2 among the following has the full outer shell ,hence option (d) is correct .

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Answer:

83.64%.

Explanation:

∵ The percent yield = (actual yield/theoretical yield)*100.

actual yield of CO₂ = 2300 g.

For the reaction:

CH₄ + 2O₂ → 2H₂O + CO₂,

1.0 mol of CH₄ react with 2 mol of O₂ to produce 2 mol of H₂O and 1.0 mol of CO₂.

no. of moles of CH₄ = mass/molar mass = (1000 g)/(16.0 g/mol) = 62.5 mol.

Using cross-multiplication:

1.0 mol of CH₄ produces → 1.0 mol of CO₂, from stichiometry.

∴ 62.5 mol of CH₄ produces → 62.5 mol of CO₂.

∴ The theoretical yield of CO₂ gas = n*molar mass = (62.5 mol)(44.0 g/mol) = 2750 g.

∵ The percent yield = (actual yield/theoretical yield)*100.

actual yield = 2300 g, theoretical yield = 2750 g.

∴ the percent yield = (2300 g/2750 g)*100 = 83.64%.

The study of chemicals and bonds is called chemistry. There are two types of metals and these are metals and nonmetals.

The correct answer to the question is 83.64.

The formation of the new compound by joining the two different elements is called a combination reaction.

According to the question

The percent yield = (actual yield/theoretical yield)*100.

Hence, the actual yield of CO₂ = 2300 g.

The reaction is as follows: - [tex]CH_4 + 2O_2 --- > 2H_2O + CO_2[/tex]

1.0 moles of CH₄ reacts with 2 moles of O₂ to produce 2 moles of H₂O and 1.0 moles of CO₂. Firstly, we need to calculate the no. of moles of 1000 g of CH₄ using the relation:

no. of moles of CH₄ = mass/molar mass =

[tex]\frac{(1000 g)}{(16.0 g/mol)} = 62.5 mol.[/tex]

Using cross-multiplication:

We can calculate the theoretical yield of carbon dioxide gas using the relation:

The theoretical yield of CO₂ gas = n*molar mass =[tex](62.5 mol)(44.0 g/mol) = 2750 g.[/tex]

∵ The percent yield = (actual yield/theoretical yield)*100.

The percent yield = [tex](2300 g/2750 g)*100 = 83.64%[/tex]%

Hence, the correct answer is 83.64.

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Answer:

[H₃O⁺] = 6.31 x 10⁻³ M.

Explanation:

pH = - log[H₃O⁺].

∴ 2.2 = - log[H₃O⁺].

∴ log[H₃O⁺] = - 2.2

∴  [H₃O⁺] = 6.31 x 10⁻³ M.

Answer:

0.85 mol/L.

Explanation:

M = (no. of moles of solute)/(Volume of the solution (L))

no. of moles of calcium phosphate = 2.125 mol.

Volume of the solution = 2.5 L.

∴ M of calcium phosphate = (2.125 mol)/(2.5 L) = 0.85 mol/L.

Answer:

PV=nRT

Explanation:

P stands for Pressure T for absolute temperature, n is the number of moles of the ideal gas which is calculated by dividing the mass of the gas by the relative molecular mass, that is, mass(grams)/ RMM, R is the univeral gas  constant=8.31441J/Kmol

Option D) PV =nRT is the correct answer.

The equation that represents pressure-volume-temperature-mole relationship of an ideal gas is PV = nRT

The Ideal gas law or general gas equation emphasizes on the state or behavior of a hypothetical ideal gas. It states that  pressure P times volume V is equal to moles times temperature and the universal gas constant. It is expressed;

[tex]PV = nRT[/tex]

Where;

Hence, Option D) PV =nRT is the correct answer.

The equation that represents pressure-volume-temperature-mole relationship of an ideal gas is PV = nRT

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Water heating on a gas-powered stove involves thermal energy and chemical energy.

Thermal energy is defined as a type of energy which is contained within a system which is responsible for temperature rise.Heat is a type of thermal energy.It is concerned with the first law of thermodynamics.

Thermal energy arises from friction and drag.It includes the internal energy or enthalpy of a body of matter and radiation.It is related to internal energy and heat .It arises when a substance whose molecules or atoms are vibrating faster.

These vibrating molecules and atoms collide and as a result of which heat is generated in a substance , more the collision of particles , higher is the thermal energy.It has 3 forms: 1) conduction 2) convection 3) radiation.

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Answer:

64 000 C; 71 min

Explanation:

1. Number of coulombs

a. Write the equation for the half-reaction.

Ca²⁺ + 2e⁻ ⟶ Ca

b. Calculate the moles of Ca

Moles of Ca = 13.3 g Ca × (1 mol Ca/40.08 g Ca) = 0.3318 mol Ca

c. Calculate the moles of electrons

Moles of electrons = 0.3318 mol Ca × (2 mol electrons/1 mol Ca) = 0.6637 mol electrons

d. Calculate the number of coulombs

No. of coulombs = 0.6637 mol electrons × (96 485 C/1 mol electrons)

= 64 000 C

It takes 64 000 C to produce 13.3 g of Ca.

2. Time required

Q  = It  

t = Q/I = 64 000 C/15 C·s⁻¹ = 4270 s

t = 4270 s × 1 min/60 s = 71 min

The process will take 71 min.

Answer:

Look at explanation

Explanation:

Size of particles increases, rate of reaction decreases, and vise versa

Catalyst causes the rate of reaction to increase

Concentration increases, rate of reaction increases, and vise versa

Temperature increases, rate of reaction increases, and vise versa