The equilibrium between carbon dioxide gas and carbonic acid is very important in biology and environmental science. CO2 (aq) + H2O (l) → H2CO3 (aq) Which one of the following is the correct equilibrium constant expression (Kc) for this reaction?a. K =[H2CO3]/ [CO2]b. K=[CO2]/ [H2CO3]c. K=[H2CO3]/ [CO2][H2O]d. K=[CO2][H2O]/ [H2CO3]e. K=1/[H2CO3]

Answer:

[tex]x_{acetone}=7.970x10^{-3}[/tex]

Explanation:

Hello,

In this case, for the given molarity, we can assume a volume of 1 L of solution, to obtain the following moles of acetone:

[tex]n=0.422mol/L*1L=0.422mol[/tex]

Then, with the density of solution, we can compute the mass of the solution for the selected 1-L volume basis:

[tex]m_{solution}=1L*\frac{1000mL}{1L}*\frac{0.970g}{1mL}=970g[/tex]

After that, we compute the mass of water in the solution, considering the mass of acetone (molar mass = 58.08 g/mol):

[tex]m_{H_2O}=970g-0.422molAcetone*\frac{58.08g\ Acetone}{1mol\ Acetone} =945.49gH_2O[/tex]

Next, the moles of water:

[tex]n_{H_2O}=945.49g*\frac{1molH_2O}{18gH_2O} =52.53molH_2O[/tex]

Finally, the mole fraction:

[tex]x_{acetone}=\frac{n_{acetone}}{n_{acetone}+n_{H_2O}}=\frac{0.422mol}{0.422mol+52.53mol}\\ \\x_{acetone}=7.970x10^{-3}[/tex]

Regards.

Answer:

677.7 mmHg

Explanation:

The first empirical study on the behaviour of a mixture of gases was carried out by John Dalton. He established the effects of mixing gases at different pressures in the same vessel.

Dalton's law states that,the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the individual gases present in the mixture of gases. When a gas is collected over water, the gas also contains some water vapour. The partial pressure of the gas will now be given as; total pressure of gas mixture - saturated vapour pressure of water (SVP) at that temperature.

Given that;

Total pressure of gas mixture = 692.2 mmHg

SVP of water at 17°C = 14.5 mmHg

Therefore, partial pressure of oxygen = 692.2-14.5

Partial pressure of oxygen = 677.7 mmHg

Answer:

a lower temperature to liquefy

Explanation:

Answer:

1.30atm

Explanation:

P1/T1 = P2/T2

1.07/393 = P2/478

Answer: the first one is correct

Explanation:

jhkfjfjgjgjjggj

Answer:

[A] = 1.438M = 1.4M (Two s.f)

Explanation:

Rate constant, k =  0.00317

Initial Concentration, [A]o = 1.44M

Final Concentration, [A] = ?

Time, t = 0.240 s

Since this is a second order reaction, the formula for this is given as;

1 / [A] = 1 / [A]o + kt

1 / [A] = 1 / 1.44 + (0.00317 * 0.240)

1 / [A] = 0.6944 + 0.0007608

1 / [A] = 0.6952

[A] = 1.438M = 1.4M (Two s.f)

Answer:

A, B and C are compounds

Explanation:

First of all, I need to establish that when carbon is burnt in excess oxygen, carbon dioxide is obtained as shown by this equation; C(s) + O2(g) ----> CO2(g).

Looking at the presentation in the question, A was said to be heated strongly and it decomposed to B and C. Only a compound can decompose when heated. Elements can not decompose on heating. Secondly, compounds usually decompose to give the same compounds that combined to form them. Compounds hardly decompose into their constituent elements.

Again from the information provided, the compound A is a white solid. This is likely to be CaCO3. It decomposes to give another white solid. This may be CaO and the gas was identified as CO2.

Hence;

CaCO3(s)--------> CaO(s) + CO2(g)

Answer:

Exothermic interractive are the following: NaOH, KOH, CaCl₂

Endothermic interactive are the following: NaCl, NH₄NO₃, NaNO₃

Explanation:

NaOH, KOH, and CaCl2 are exothermic reactants. NaCl, NH4NO3, and NaNO3 are endothermic interacting substances.

Chemical processes that can release or absorb energy are referred to as endothermic. In endothermic reactions, more energy is used when bonds in the reactants are broken than is released when new bonds are formed in the products.

When the temperature of the an isolated system drops while the surroundings of the a non-isolated system warm up, this is known as an endothermic response. The heat of reaction is generally positive in endothermic processes (qrxn>0).

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Answer:

d

Explanation:

Answer:

The third reaction

(2NaOH + NiCL2 ---> 2NaCl + Ni(OH)2)

Explanation:

By definition, a precipitation reaction refers to the formation of an insoluble salt when two solutions containing soluble salts are combined.

(Source: lumenlearning)

From the 4 options, we can eliminate the first and second one immediately because there is no formation of an insoluble salt.

Then, the last one can also be eliminated because even though there is insoluble solid formed, but it is not a salt, and, the reactants are not solutions too. In fact, the last one is a displacement reaction. A more reactive metal displaces a less reactive metal to form an ion.

Since the third reaction matches the definition of precipitation reaction, this is the answer.

Answer:

33.3% of Sn in the sample

Explanation:

The addition of SO₄⁻ ions produce the selective precipitation of Pb²⁺ to produce PbSO₄.

Moles of PbSO₄ (molar mass 303.26g/mol) in 2.93g are:

2.93g ₓ (1mol / 303.26) = 9.66x10⁻³ moles PbSO₄ = Moles Pb²⁺.

As molar mass of Pb is 207.2g/mol, mass in 9.66x10⁻³ moles of Pb²⁺ is:

9.66x10⁻³ moles of Pb²⁺ ₓ (207.2g / mol) = 2.00g of Pb²⁺

As mass of the sample is 3.00g, mass of Sn²⁺ is 3.00g - 2.00g = 1.00g

And the percentage of Sn in the sample is:

1.00g / 3.00g ₓ 100 =

Answer:

Molarity

Explanation:

The conversion of g/mol to g/L molarity can be used. Thus, option C is correct.

The g/mol has been the amount of solute present in a mole. The g/mol has been the molecular weight of the compound.

The g/L has been the mass of solute present in a L of solution. The g/L has  the unit for density.

Molarity has been the moles of solute present in the liter of solution. It has been given as mol/L.

The product of g/mol and g/L gives the value of mol/L. Thus, to convert g/mol to g/L molarity can be used. Thus, option C is correct.

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Answer:

1.5 L  

Explanation:

If the gas is contained in a steel tank, the volume will remain constant when the temperature changes.

The volume will be 1.5 L.

Answer: [H2SO4] = 0.5M;

              [KOH] = 1M

Explanation: Molarity is the solution concentration defined by:

molarity = [tex]\frac{mol}{L}[/tex] or M

To determine the concentration of the mixture, find how many mols of each compound there are in the mixture:

50 mL = 0.05L

H2SO4

1 mol/L * 0.05L = 0.05mol

KOH

2mol/L * 0.05L = 0.1 mol

The mixture has a total volume of:

V = 50 + 50 = 100 mL = 0.1 L

The concentration of the resullting solutes:

[H2SO4] = [tex]\frac{0.05}{0.1}[/tex] = 0.5 M

[KOH] = [tex]\frac{0.1}{0.1}[/tex] = 1 M

Concentration of H2SO4 is 0.5M while for KOH is 1M.

Answer:

3-bromobenzoic acid

Explanation:

In this case, we have to remember that the [tex]Br_2/FeBr_3[/tex]  is a reaction in which we add Br into the molecule an electrophilic aromatic substitution. Additionally, we have a carboxylic acid in the benzene. This carboxylic acid is an ortho director because is a deactivating group (it removes electrons from the benzene ring). With this in mind, a "Br" atom would be added in an ortho position respect to the COOH group and we will obtain 3-bromobenzoic acid.

See figure 1.

I hope it helps!

To create 3-bromobenzoic acid, a "Br" atom would be placed at an orthogonal position to the COOH group according to electrophilic aromatic substitution.

Electrophilic aromatic substitution is a type of organic reaction in which an atom or group in an aromatic ring is substituted with an electrophile. It is a fundamental reaction in aromatic chemistry that happens due to the aromatic system's high electron density.

It is an electrophilic aromatic substitution process in which Br is incorporated into the molecule. In addition, the benzene contains a carboxylic acid. Because it removes electrons from the benzene ring, this carboxylic acid functions as an ortho director. To create 3-bromobenzoic acid, a "Br" atom would be placed at an orthogonal position to the COOH group. The product is seen in the photographs below.

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Answer: B. 430 K

Explanation:

According to Gibb's equation:

[tex]\Delta G=\Delta H-T\Delta S[/tex]

[tex]\Delta G[/tex] = Gibbs free energy  

[tex]\Delta H[/tex] = enthalpy change  = +62.4 kJ/mol

[tex]\Delta S[/tex] = entropy change  = +0.145 kJ/molK

T = temperature in Kelvin

[tex]\Delta G[/tex]  = +ve, reaction is non spontaneous

[tex]\Delta G[/tex]  = -ve, reaction is spontaneous

[tex]\Delta G[/tex]  = 0, reaction is in equilibrium

[tex]\Delta H-T\Delta S=0[/tex] for reaction to be spontaneous

[tex]T=\frac{\Delta H}{\Delta S}[/tex]

[tex]T=\frac{62.4kJ/mol}{0.145kJ/molK}=430K[/tex]

Thus the Reaction is spontaneous when temperature is 430 K.

Answer:

430 K

Explanation:

i just took the test on a pex :)

Answer:

The total surface area of these N spherical droplets is 4.4929 m²

Explanation:

From the information given :

assuming that :

30 cm³ of gasoline is atomized into N spherical droplets &

each with a radius of 2.0 × 10−5 m

We are tasked to determine the total surface area of these N spherical droplets

We all known that:

[tex]1 \ cm^3 = 10 ^{-6} m^3[/tex]

Therefore

[tex]30 \ cm^3 = 30 * 10 ^{-6} m^3 = 3 *1 0^{-5} \ m^3[/tex]

For each droplet; there is a required volume which is = [tex]\dfrac{4}{3} \pi r ^3[/tex]  since it assumes a sphere shape .

Thus;

replacing radius(r) with 2.0 × 10−5 m; we have:

[tex]= \dfrac{4}{3} \pi * (2.0 *10^{-5} m) ^3[/tex]

= [tex]3.35 * 10^{-14} \ m^3[/tex]

However; there are [tex]3*10^{-5} \ m^3[/tex] gasoline atomized into N spherical droplets with each with radius 2.0 × 10−5 m

For N ; we have ;

[tex]=\dfrac{3*10^{-5} \ m^3}{3.35 * 10^{-14} \ m^3/ droplet}[/tex]

= [tex]8.95*10^8 \ droplet s[/tex]

So; each droplet have a surface area = [tex]4 \pi r^2[/tex]

= [tex]4 \pi (2.0*10^{-5}m) ^2[/tex]

= [tex]5.02*10^{-9} \ m^2/droplets[/tex]

The surface area per droplet is equivalent to [tex]5.02*10^{-9} \ m^2/droplets[/tex]

Thus;

The total surface area of these N spherical droplets will be :

= [tex]8.95*10^8 \ droplet s * 5.02*10^{-9} \ m^2/ droplets[/tex]

= 4.4929 m²

The total surface area of these N spherical droplets is 4.4929 m²

Answer:

pH = 9.58

Explanation:

First of all, we need to determine the molarity of the solution.

We determine the molar mass of morphine:

12g/m . 17 + 1 g/m . 19 + 14 g/m + 16 g/m . 3 = 285.34 g/m

molar mass g/m, is the same as mg/mm

25 mg . 1 mmol / 285.34 mg = 0.0876 mmoles / 100 mL = 8.76×10⁻⁴ M

In diltuted solution, we must consider water.

Mass balance for morphine = [Morphine] + [Protonated Morphine]

8.76×10⁻⁴ M = [Morphine] + [Protonated Morphine]

As Kb is too small, I can skipped, the [Protonated Morphine]

8.76×10⁻⁴ M = [Morphine]

In the charge balance I will have:

[OH⁻] = [H⁺ morphine] + [H⁺]

Let's go to the Kb expression

Morphine + H₂O  ⇄  MorphineH⁺  +  OH⁻        Kb

Kb = [MorphineH⁺]  [OH⁻] / [Morphine]

Kb = [MorphineH⁺]  [OH⁻] / 8.76×10⁻⁴ M

So now, we need to clear [MorphineH⁺] to replace it in the charge balance

Kb  . 8.76×10⁻⁴ M / [OH⁻] = [MorphineH⁺]

Now, the only unknown value is the [OH⁻]

[OH⁻] = Kb .  8.76×10⁻⁴ M / [OH⁻]  + Kw/[OH⁻]

Remember that Kw = [H⁺] . [OH⁻]

[H⁺] = Kw/[OH⁻]

[OH⁻]² = 1.62×10⁻⁶ . 8.76×10⁻⁴ + 1×10⁻¹⁴

[OH⁻] = √(1.62×10⁻⁶ . 8.76×10⁻⁴ + 1×10⁻¹⁴)

[OH⁻] = 3.76×10⁻⁵  →  - log [OH⁻] = pOH = 4.42

pH = 14 - pOH  →  14 - 4.42 = 9.58

Answer:

The incorrect statement from the options is OXIDATION IS A "GAIN" OF ELECTRONS

Explanation:

Oxidation in a redox reaction is the loss of electrons. It is also the increase in the oxidation states of an atom or ion or atoms in a molecule. A redox reaction is a type of chemical reaction in which there is a transfer of electrons from an atom or ion to another resulting in a change in oxidation states of the substances involved. The reducing agent in the reaction is undergoes oxidation by losing electrons while the oxidating agent is reduced that is it gains electrons at the end of the reaction. The atom or ion from which electron is lost is said to be oxidized while the other atom or ion involved in the reaction is reduced.

Oxidation is also the combination with O atoms and it is always accompanied by reduction because oxidation forms a half of the whole redox reaction. A substance cannot be oxidized except it has reduced another substance by losing electrons to it.

Answer:

MgO

Explanation:

The following data were obtained from the question:

mass of crucible and cover + magnesium metal = 33.741 g

mass of crucible and cover = 33.5 g

mass of crucible and cover + magnesium oxide = 33.899 g

Next, we shall determine the mass of magnesium metal. This can be obtained as follow:

mass of crucible and cover + magnesium metal = 33.741 g

mass of crucible and cover = 33.5 g

Mass of magnesium metal =..?

Mass of magnesium metal = (mass of crucible and cover + magnesium metal) – (mass of crucible and cover)

Mass of magnesium metal = 33.741 – 33.5

Mass of magnesium metal = 0.241g

Next, we shall determine the mass of magnesium oxide. This can be obtained as follow:

mass of crucible and cover + magnesium oxide = 33.899 g

mass of crucible and cover = 33.5 g

Mass of magnesium oxide =?

Mass of magnesium oxide = (mass of crucible and cover + magnesium oxide) – (mass of crucible and cover)

Mass of magnesium oxide = 33.899 –. 33.5

Mass of magnesium oxide = 0.399g

Next, we shall determine the mass of oxygen. This can be obtained as follow:

Mass of magnesium oxide = 0.399g

Mass of magnesium metal = 0.241g

Mass of oxygen =..?

Mass of oxygen = (Mass of magnesium oxide) – (Mass of magnesium metal)

Mass of oxygen = 0.399 – 0241

Mass of oxygen = 0.158g

Now, we can obtain the empirical formula for the magnesium oxide as follow:

Mg = 0.241g

O = 0.158g

Divide by their molar mass

Mg = 0.241 / 24 = 0.01

O = 0.158 / 16 = 0.0099

Divide by the smallest

Mg = 0.01 / 0.0099 = 1

O = 0.0099 / 0.0099 = 1

Therefore, the empirical formula for the magnesium oxide is MgO

Answer:

Thrust.

Explanation:

hope this helps you :)

Answer:

thrust

Explanation:

Answer:

[tex]Pb(CO_{3})_{2} \\Pb(NO_{3})_{4} \\FeCO_{3}\\Fe(NO_{3})_{2}[/tex]

Explanation:

[tex]Pb^{4+}(CO_{3}^{2-})_{2} --->Pb(CO_{3})_{2} \\Pb^{4+} (NO_{3}^{-})_{4} --->Pb(NO_{3})_{4} \\Fe^{2+} CO_{3}^{2-} --->FeCO_{3}\\Fe^{2+} (NO_{3}^{-})_{2}--->Fe(NO_{3})_{2}[/tex]

Answer:

Molecules = 7.5 × 10²³ molecules

Explanation:

Given:

Moles = 1.25 mol

Avogadro's No. = [tex]N_{A}[/tex] = 6.022 * 10²³

Required:

Molecules = ?

Formula:

Molecules = Moles × [tex]N_{A}[/tex]

Solution:

Molecules = 1.25 × 6.022 × 10²³

Molecules = 7.5 × 10²³ molecules

Answer:

d) El agua pesada contiene mas elementos

Explanation:

La diferencia fundamental entre el agua pesada y el agua ligera es que la primera tiene una proporción mayor de deuterio que la segunda. El deuterio es un ión del hidrógeno que tiene un peso atómico mayor que el hidrógeno común y corriente. Por ende, la opción D ofrece la mejor aproximación.

Answer:

....................

lllllllllllllllll

Explanation:ki

Answer:

Mechanical to Heat

explanation:

The wood itself can make mechanical energy but when it's on fire it makes heat energy

Answer: Chemical to heat and light

Explanation: The energy transforms from chemical energy to heat and light energy. Because when the candle burns a chemical reaction occurs and produces heat and light.

Answer:

"The active site of the enzyme has a complementary rigid structure" belongs to the key and lock system

"The conformation of the enzyme changes when it binds to the substrate so that the active site conforms to the substrate." belongs to the induced fit system.

"The substrate binds to the enzyme at the active site, forming an enzyme-substrate complex" belongs to both, that is, the key and lock system and the induced fit system.

"The substrate binds to the enzyme through non-covalent interactions" can belong to both enzyme systems.

Explanation:

Enzymatic key and lock systems bear this name because the enzyme at its site of union with the substrate has an ideal shape so that its fit is perfect, similar to a headbreaker, so once they are joined they are not It can bind another substrate to the enzyme, since they are generally associated with strong chemical bonds.

The shape of the enzyme's active site is a negative of what the shape of the substrate would be.

On the other hand, in the mechanism or enzyme system of induced adjustment, the enzyme has an active site that is where it binds with the substrate and another site where another chemical component binds, which when this chemical component binds this enzyme changes its morphology and becomes "active" to bond with your substrate.

This happens a lot in the inactive enzymes that are usually activated in digestive processes since the fact that these enzymes are constantly active would be dangerous, therefore the body takes the induced enzyme system as a control mechanism, where a molecule or chemical compound induces change morphological of an enzyme by means of the allosteric union so that it joins its substrate and catalyzes or analyzes it, depending on the enzymatic character of the enzyme.

Answer:

0.623 M

Explanation:

Step 1: Given data

Step 2: Calculate the percent by volume (%m/v)

We will use the following expression.

[tex]\%m/v = \%m/m \times \rho = 7.00\% \times 1.071g/mL = 7.50g\%mL[/tex]

Step 3: Calculate the molarity

7.50 g of magnesium sulfate are dissolved in 100 mL of the solution. The molarity is:

[tex]M = \frac{7.50g}{120.37g/mol \times 0.100L } = 0.623 M[/tex]

Answer:

Option D is correct.

n = 6 to n = 2

Explanation:

Like all waves emitted from the movement of electrons from one energy level to another, the wavelength (λ) is given by the equation involving Rydberg's constant

(1/λ) = Rₕ [(1/n₂²) - (1/n₁²)]

where Rₕ = 10973731.57 m⁻¹ = (1.0974 × 10⁷) m⁻¹

n₂ = principal quantum number corresponding to the final energy level of the electron = 2 (For Balmer Series)

n₁ = principal quantum number corresponding to the final energy level of the electron = ?

λ = 410 nm = (410 × 10⁻⁹) m

(1/λ) = (2.439 × 10⁶) m⁻¹

2.439 × 10⁶ = (1.0974 × 10⁷) [(1/2²) - (1/n₁²)]

0.25 - (1/n₁²) = (2.439 × 10⁶) ÷ (1.0974 × 10⁷) = 0.2222602562

(1/n₁²) = 0.25 - 0.2222602562 = 0.0277397438

n₁² = (1/0.0277397438) = 36.05

n₁ = 6

Hope this Helps!!!

Answer:

Wavelength, λ  = 6.7 x 10^-11 m

Explanation:

Frequency and wavelength are inversely proportional to each other.

In this problem;

f =  4.5 x 10^18 Hz

wavelength, λ = ?

Speed of light, c = 3 x 108 m/s.

These variables are related by the following equation;

c = λ * f

Making λ subject of focus, we have;

λ = c / f

λ = 3 x 10^8 / 4.5 x 10^18

λ  = 0.67 x 10^-10

λ  = 6.7 x 10^-11 m

Answer:

I would put A

Explanation:

A new substance is produced as a result of a chemical reaction in which bonds between the molecules of the reactant and product are broken and new bonds are formed. Here the products are Al₂O₃ and Fe. The correct option is A.

Chemical reactions are interactions between two or more molecules that result in the production of new products. Products, as opposed to reactants, are compounds that result from an interaction between two other substances.

The reactants are on the left, while the products that are created are on the right. A one-headed or two-headed arrow connects the reactants and products.

Thus the correct option is A.

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Combining quantum theory with wave motion of atomic particles is: Wave Mechanics