The diagram shows a pump. Which labels can replace
X and the Y in the diagram?
X: potassium, Y: sodium
X: sodium, Y potassium
X: sodium, Y: calcium
X: calcium, Y: potassium ​

No where.. unless there are places that have very heavy rain fall and pollution at the same time like New York (sometimes). A place where it is not really a problem could be like Hawaii, were there is less industrial pollution getting released into the air. I hope this helps!! lol

Answer:

China and india is more of the problem and the part is least of the problem is North Eastern United States, Eastern Europe

Explanation:

Answer:

NaNO3

Explanation:

The species where nitrogen has the highest oxidation number is NaNO3, where nitrogen has an oxidation number of +5.

The species where nitrogen has the highest oxidation number is NaNO3. In this compound, the oxidation number of nitrogen is +5. We can determine this by understanding that the oxidation number for oxygen is usually -2, and for sodium it is usually +1. Therefore, to balance the charge in the compound NaNO3(sodium nitrate), nitrogen must have an oxidation state of +5.

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Answer:

50 mL

Explanation:

We can solve this problem by using Boyle's Law, which states that:

"For a fixed mass of an ideal gas kept at constant temperature, the pressure of the gas is inversely proportional to its volume"

Mathematically:

[tex]p\propto \frac{1}{V}[/tex]

where

p is the pressure of the gas

V is the volume of the gas

The equation can be rewritten as

[tex]p_1 V_1 = p_2 V_2[/tex]

where in this problem:

[tex]p_1 = 100 kPa[/tex] is the initial pressure of the gas in the coke

[tex]V_1=25 mL[/tex] is the initial volume

[tex]p_2=50 kPa[/tex] is the final pressure

Solving for V2, we find the final volume:

[tex]V_2=\frac{p_1 V_1}{p_2}=\frac{(100)(25)}{50}=50 mL[/tex]

Answer:

T = 0.38 K

Explanation:

Given data:

Number of moles = 4.75 mol

Pressure = 1.2 atm

Volume = 0.125 L

R = 0.0821 atm.L /mol.K

Temperature = ?

Solution:

Formula:

PV = nRT

T = PV/nR

T = 1.2 atm × 0.125 L /  4.75 mol × 0.0821 atm.L /mol.K

T = 0.15  / 0.39 /K

T = 0.38 K

Question:

1 State what happens to the average kinetic energy of the gas molecules if the cabin

temperature decreases.

2 Show a numerical setup for calculating the pressure in the submarine cabin if the cabin

temperature changes to 293 K.

3 Determine the number of moles of CO₂(g) in the submarine cabin at which the air

becomes unsafe to breathe. The gram-formula mass of CO₂ is 44.0 g/mol.

4 Convert the original air pressure in the cabin of the submarine to atmospheres.

Answer:

1) The average kinetic energy of the gas molecules will decrease

2) P₂ = 293 K × 116 kPa/312 K = 108.94 kPa

3) 49 mols

4) 116 kPa  = 1.145 atm

Explanation:

(1) When the cabin temperature decreases, the pressure within the cabin will decrease because the average kinetic energy of the gas molecules will decrease. That is the gas particles will have a lower speed.

(2) P₁V₁/T₁ = V₂P₂/T₂

Since the volume is constant we have

116 kPa/312 K = P₂/293 K

P₂ = 293 K × 116 kPa/312 K = 108.94 kPa

(3)  

Since CO₂ is 44.0 g/mol, we have

2156/44 = 49 mols

(4) 1 atm = 101325 Pa

Therefore 116 kPa = 1/101325 ×116000 = 1.145 atm

Answer:

1) The average kinetic energy of the gas molecules will decrease

2) P₂ = 293 K × 116 kPa/312 K = 108.94 kPa

3) 49 mols

4) 116 kPa = 1.145 atm

Explanation:

Answer:  The mole ratio of atoms or ions in the compound

Explanation:

Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass. It can be decomposed into simpler constituents using chemical reactions. Example: water with chemicl formula [tex]H_2O[/tex]

The subscript 2 in [tex]H_2O[/tex] represents that the ratio of hydrogen atom is twice that of oxygen atom.

Thus SUBSCRIPTS in a compound represent the mole ratio of atoms or ions in the compound

Answer:

See below

Explanation:

When a strip of zinc metal is placed into a blue solution of copper(II) nitrate, a reaction immediately begins as the zinc strip begins to darken. If left in the solution for a longer period of time, the zinc will gradually decay due to oxidation to zinc ions.

Answer::Molarity = 0.08 MExplanation:Given data:Mass of sodium carbonate = 10.6 gVolume of water = 1.25 LMolarity of solution = ?Solution:First of ... 10.6 grams of Na2CO3 is dissolved in water to make 1.25 liters of solution.

Answer:

The initial pressure exerted on the balloon is 7.0 atm.

Explanation:

To calculate the new volume, we use the equation given by Boyle's law. This law states that pressure is inversely proportional to the volume of the gas at constant temperature.

The equation given by this law is:

[tex]P_1V_1=P_2V_2[/tex]

where,

[tex]P_1\text{ and }V_1[/tex] are initial pressure and volume.

[tex]P_2\text{ and }V_2[/tex] are final pressure and volume.

We are given:

Initial pressure of helium gas in balloon = [tex]P_1=?[/tex]

Initial volume of helium gas in balloon = [tex]V_1=7.2 L[/tex]

Final pressure of helium gas in balloon = [tex]P_2=2.00 atm[/tex]

Final volume of helium gas in balloon = [tex]V_2=25.1 L[/tex]

Putting values in above equation, we get:

[tex]P_1\times 7.2 L=2.00 atm\times 25.1 L[/tex]

[tex]P_1=\frac{2.00 atm\times 25.1 L}{7.2 L}=6.97 atm\approx 7.0 atm[/tex]

Hence, the initial pressure exerted on the balloon is 7.0 atm.

Answer:

The answer to your question is below

Explanation:

Data

density = 13.53 g/cm³

volume = 62.5 cm³

mass = ?

moles = ?

atoms = ?

Process

1.- Calculate the mass of mercury

formula

density = mass/volume

-Solve for mass

mass = density x volume

-Substitution

mass = 13.53 x 62.5

-Result

mass = 845.63 grams

2.- Calculate the moles of mercury

Atomic mass = 200.6 g

              200.6 g of mercury --------------------- 1 mol

              845.63 g of mercury --------------------  x

                   x = (845.63 x 1) / 200.6

                   x = 4.22 moles of mercury

3.- Calculate the number of atoms

               1 mol --------------------  6 .023 x 10 ²³ atoms

             4.22 moles -------------   x

                 x = (4.22 x 6.023 x 10²³) / 1

                x = 2.54 x 10²³ atoms

Answer:

The volume for the ideal gas is: 4647.5 Liters

Explanation:

Formula for the Ideal Gases Law must be applied to solve this question:

P . V = n .  R . T

We convert the T° to K → 100°C + 273 = 373 K

We convert pressure value from kPa to atm.

2 kPa . 1atm/101.3 kPa = 0.0197 atm

We replace data in the formula.

V = ( n . R . T) / P → (3 mol . 0.082 . 373K) / 0.0197 atm =

The volume for the ideal gas is: 4647.5 Liters

Answer:

Carbon tends to bond covalently with Hydrogen

Answer:

All the carbon group atoms, having four valence electrons, form covalent bonds with nonmetal atoms; carbon and silicon cannot lose or gain electrons to form free ions, whereas germanium, tin, and lead do form metallic ions but only with two positive charges.

Explanation:

Answer:

The percent yield of the reaction is 90.9%.

Explanation:

Mass of hydrogen gas = 24.2 g

Moles of hydrogen = [tex]\frac{24.2 g}{2g/mol}=12.1 mol[/tex]

[tex]2H_2+O_2\rightarrow 2H_2O[/tex]

According to reaction, 2 moles of hydrogen gas gives 2 moles of water , then 12.1  moles of hydrogen will give:

[tex]\frac{2}{2}\times 12.1mol=12.1mol[/tex]  water

Mass of 12.1 moles of water

= 12.1 mol × 18 g/mol = 217.8 g

Theoretical yield of water = 217.8 g

Experimental yield of water = 198 g

The percentage yield of reaction:

[tex]=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100[/tex]

[tex]=\frac{198 g}{217.8 g}\times 100=90.9\%[/tex]

The percent yield of the reaction is 90.9%.

Answer:

The answer to your question is Na₂S, if you need to choices the other one is BaS

Explanation:

As a general rule, all the compounds that have sulfur, are insoluble in water, but the are some exceptions.

-Molecules with ammonia

-If the molecule has alkali metals is soluble

-If the molecule has Ca⁺², Sr⁺² and Ba⁺² is soluble in water.

From the compounds given, following the rules, the compound that is soluble in is Na₂S and perhaps BaS.

Among PbS, BaS, Na2S, and Fe2S3, Na2S is the compound that is soluble in water, as sodium is a Group I element and its sulfide does not follow the general rule of insolubility for sulfides.

The question concerns the solubility of compounds in water, which is a topic in Chemistry. Among the compounds listed (PbS, BaS, Na2S, Fe2S3), Na2S (sodium sulfide) is the one that is soluble in water. This is because Na+ is a Group I element, and as per solubility rules, sulfides are generally insoluble except for those of Group I elements and also calcium, strontium, and barium to a lesser extent. Despite barium being part of the exception, BaS tends to hydrolyze and form Ba(OH)2 and H2S, making it not truly soluble in water for practical purposes. On the other hand, PbS (lead sulfide), Fe2S3 (iron(III) sulfide), and BaS (barium sulfide) are typically insoluble due to their placement on the periodic table as transition metals or heavy metals, which generally form insoluble sulfides.

Answer:

B.

Explanation:

gas equation is PV = nRT

R = PV/nT

Final answer:

The ideal gas constant R is calculated from the ideal gas law PV = nRT as R = (PV)/(nT) by dividing both sides of the equation by n and T. THus, option B is correct.

Explanation:

The ideal gas constant, denoted as R, is a factor in the ideal gas law, which is expressed as PV = nRT. To find the value of R, we can rearrange this equation to solve for R. Therefore, the correct equation to calculate R using the ideal gas law would be R = (PV)/(nT). This rearrangement comes from simply dividing both sides of the ideal gas law by n and T to isolate R.

Answer:

The volume occupies of neon gas is 335, 7 L

Explanation:

We use the formula PV=nRT. We convert the unit temperature Celsius into Kelvin: 0°C=273 K---> -28°C= -28+273= 245K. We calculate the number of mols in 322 grams of neon:

20,18 g---1 mol neon

322g---x= (322g x 1 mol neon)/ 20, 18g=15, 96 mol neon

PV=nRT    ----> V= (nRT)/P

V= (15,96 mol x 0,082 l atm/K mol x 245 K)/ 0,955 atm= 335, 7 L

Answer:

V1P1=V2P2

155(22L)=P(10L0

P=341kPg

Explanation:

The following format is copied directly from your notes for how to solve these!!!

1) Analyze problem statement to find knowns and unknowns for each gas variable

V1 = 22.0 L P1 = 155.0 kPa T1 = T2 n = constant (same sample of gas)

V2= 10.0 L P2 = ? kPa T2 = T1 temperature is constant

2) Decide which of the gas laws to use and write its formula.

Only P and V are given, so Boyle's law is used P1V1 = P2V2

3) Change any temperature values to Kelvin (if T is needed) not needed

4) Plug in the knowns - INCLUDING UNITS!!

P1V1 = P2V2

(155.0 kPa) (22.0 L) = P2 (10.0 L)

P2 = (155.0 kPa)(22.0 L) = 341 kPa

(10.0 L)The following format is copied directly from your notes for how to solve these!!!

1) Analyze problem statement to find knowns and unknowns for each gas variable

V1 = 22.0 L P1 = 155.0 kPa T1 = T2 n = constant (same sample of gas)

V2= 10.0 L P2 = ? kPa T2 = T1 temperature is constant

2) Decide which of the gas laws to use and write its formula.

Only P and V are given, so Boyle's law is used P1V1 = P2V2

3) Change any temperature values to Kelvin (if T is needed) not needed

4) Plug in the knowns - INCLUDING UNITS!!

P1V1 = P2V2

(155.0 kPa) (22.0 L) = P2 (10.0 L)

P2 = (155.0 kPa)(22.0 L) = 341 kPa

(10.0 L)

Final answer:

By applying Boyle's law, which states the inverse relationship between volume and pressure at constant temperature, we can calculate the new pressure of a gas when its volume changes. The new pressure is of 341.0 kPa.

Explanation:

The question provided discusses the behavior of gases under different conditions of pressure, volume, and temperature. This is a chemistry concept known as Boyle's law when temperature is constant, or Gay-Lussac's law when pressure is constant, or the combined gas law when neither are constant.

With the information given, we are asked to calculate the new volume or pressure of a gas sample when one of the other variables changes, while holding the other constant.

If the temperature remains constant (Boyle's law), the pressure of a gas is inversely proportional to its volume (P1V1 = P2V2). In the first example, to find the new pressure when the volume decreases from 22.0 L to 10.0 L, while starting at 155.0 kPa, the formula is rearranged to P2 = (P1V1) / V2.

Thus the new pressure is (155.0 kPa × 22.0 L) / 10.0 L, resulting in a new pressure of 341.0 kPa.

Answer : The volume of gas occupy at [tex]1.00\times 10^2^oC[/tex] is, 1.25 L

Explanation :

Charles' Law : It states that volume of the gas is directly proportional to the temperature of the gas at constant pressure and number of moles.

Mathematically,

[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]

where,

[tex]V_1\text{ and }T_1[/tex] are the initial volume and temperature of the gas.

[tex]V_2\text{ and }T_2[/tex] are the final volume and temperature of the gas.

We are given:

[tex]V_1=1.00L\\T_1=25.0^oC=(25.0+273)K=298K\\V_2=?\\T_2=1.00\times 10^2^oC=((1.00\times 10^2)+273)K=373K[/tex]

Putting values in above equation, we get:

[tex]\frac{1.00L}{298K}=\frac{V_2}{373K}\\\\V_2=1.25L[/tex]

Therefore, the volume of gas occupy at [tex]1.00\times 10^2^oC[/tex] is, 1.25 L

The given reaction is a synthesis reaction which will generate approximately 45.5g of NaCl, following conversion from moles to grams.

The reaction in question is a synthesis reaction between sodium (Na) and chlorine (Cl_2) to produce sodium chloride (NaCl). The balanced chemical equation for this reaction is 2Na + Cl_2 → 2NaCl, which tells us that the ratio of moles of sodium to moles of sodium chloride is 1:1. Thus, the moles of sodium is equal to the moles of sodium chloride produced.

To calculate this, you would first need to convert grams of sodium to moles using its molar mass (approximately 23 g/mol). Therefore, 18.0 g of Na equals about 0.78 moles. Since the ratio of Na to NaCl in the reaction is 1:1, this means that the reaction would yield 0.78 moles of NaCl.

To convert this to grams, you multiply by the molar mass of NaCl (approximately 58.44 g/mol). So, approximately 45.5g of NaCl would be produced from 18.0 g of Na and sufficient Cl_2

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Answer:

18.5 grams

Explanation:

The first step is to balance the equation.

2LiOH+CO2⇒Li2CO3+H2O+ some extra oxygen

For CO2, carbon has a molar mass of about 12, and oxygen has a molar mass of about 16, so the total is 44. Now that the equation is balanced and there are two LiOH's, it's molar mass is now doubled and it effectively has a molar mass of 48. 12/48=0.25 moles of both original substances used, and 0.25 moles of the final products. Li2CO3 has a molar mass of 7*2+12+16*3=74, and multiplying this by the 0.25 moles yields 18.5 grams. Hope this helps!

Answer:

18.5 grams [tex]Li_{2}CO_{3}[/tex]

Explanation:

First, we'll need to balance the equation:

[tex]LiOH_{s} + CO_{2(g)}[/tex] → [tex]Li_{2}CO_{3(s)} + H_{2}O_{(l)}[/tex]

There is one (Li) on the left and two on the right, so let's add a 2 coefficient on the left.

[tex]2LiOH_{s} + CO_{2(g)}[/tex] → [tex]Li_{2}CO_{3(s)} + H_{2}O_{(l)}[/tex]

Now there are 2 (Li) on the left, and 2 on the right, 4 (O) on both sides, 1 (C) on both sides, and 2 (H) on both sides. The equation is balanced!

Step 1: Find the limiting reactant

To find the limiting reactant, we need to convert the given masses of each reactant into moles. Multiply the given masses by the molar masses.

12g 2LiOh × [tex]\frac{1 mol}{48 g}[/tex](double the molar mass because you have two molecules) = 0.25 moles

12g CO₂ × [tex]\frac{1 mol}{44.01 g}[/tex] = 0.272 moles

We'll test both reactants to see which one limits us.

Since we don't have enough CO₂ to use all of our LiOH, CO₂ is the limiting reactant. We will use all of the CO₂ to perform our reaction and ignore the excess LiOH.

Step 2: Calculating the mass of the product

You can find the mass of either product with a mole ratio. (Remember, we have too much CO₂, so we'll need to use the given LiOH to perform this calculation)

0.25 moles LiOH × [tex]\frac{1 mole CO_{2}}{1 mole Li_{2}CO_{3}}[/tex] = 0.25 moles [tex]Li_{2}CO_{3}[/tex]

Now we convert back to grams!

0.25 moles [tex]Li_{2}CO_{3}[/tex] × [tex]\frac{74 g}{1 mole}[/tex] = 18.5 grams

Answer:

Classify the following mixtures as homogeneous or heterogeneous

a. A bucket with balls of different color  heterogeneous mixture

b. Beach sand homogeneous mixture

c. A sample of salt with water homogeneous mixture

d. Air homogeneous mixture

e. Blood homogeneous mixture

f. A fruit salad  heterogeneous mixture

g. Ice cubes with water  heterogeneous mixture

h. Window glass homogeneous mixture

i. Pond water homogeneous mixture

j. The soup  heterogeneous mixture

l. Wood homogeneous mixture

m. Gasoline homogeneous mixture

n. Powder homogeneous mixture

o. Orange heterogeneous mixture

p. Cement homogeneous mixture

q. Engine oil homogeneous mixture

r. Cotton homogeneous mixture

s. Paper homogeneous mixture

t. Oil and Vinegar  heterogeneous mixture

k. Smog homogeneous mixture

Explanation:

In homogeneous mixtures, the elements are united in such a way that they are not distinguishable, while in heterogeneous mixtures, these are observable.

Answer:

Explanation:

The chemical reaction involved is as follows

H₃BO₃ + 4HF = HBF₄ + 3H₂O

1 mol                  1 mol

mol weight of H₃BO₃ is 61.84 gm

50g = 50 / 61.84 mol.

= 0.8 mol.

.8 mol of H₃BO₃ will form .8 mol of BF₄⁻ ion .

This is an incomplete question, here is a complete question.

For each reaction, identify the Bronsted-Lowry acid, the Bronsted-Lowry base, the conjugate acid, and the conjugate base.

[tex]HBr(aq)+H_2O(l)\rightleftharpoons H_3O^+(aq)+Br^-(aq)[/tex]

Express your answers as a chemical expressions. Enter your answers in order given in the question separated by commas.

Answer : The given equilibrium reaction will be,

[tex]HBr(aq)+H_2O(l)\rightleftharpoons H_3O^+(aq)+Br^-(aq)[/tex]

Acid            Base      Conjugate    Conjugate

                                       acid             base

Explanation :

According to the Bronsted Lowry concept, Bronsted Lowry-acid is a substance that donates one or more hydrogen ion in a reaction and Bronsted Lowry-base is a substance that accepts one or more hydrogen ion in a reaction.

Or we can say that, conjugate acid is proton donor and conjugate base is proton acceptor.

The given equilibrium reaction will be,

[tex]HBr(aq)+H_2O(l)\rightleftharpoons H_3O^+(aq)+Br^-(aq)[/tex]

Acid            Base      Conjugate    Conjugate

                                       acid             base

In this reaction, [tex]HBr[/tex] is an acid that donate a proton or hydrogen to [tex]H_2O[/tex] base and it forms [tex]Br^-[/tex] and [tex]H_3O^+[/tex] are conjugate base and acid respectively.

The formula HBr(aq)+H2O(l)→H3O+(aq)+Br−(aq) represents a Brønsted-Lowry Acid-Base reaction where HBr donates a proton to H2O, forming H3O+ and Br-. This is an acid-base reaction in an aqueous solution.

The provided chemical reaction between Hydrobromic acid and water is a characteristic of Brønsted-Lowry Acid-Base reaction. In this reaction, HBr (Hydrobromic acid) donates a proton (H+) to H2O (water), which is a proton acceptor. This process results in the formation of Hydronium Ion (H3O+) and Bromide Ion (Br-).

Expressing the reaction step by step, we start with HBr(aq)+H2O(l), wherein the Hydrobromic acid dissociates into a proton (H+) and a bromide ion (Br-). Similarly, water dissociates into Hydronium Ion (H3O+). Hence, HBr(aq)+H2O(l)→H3O+(aq)+Br−(aq). This is an example of an acid-base reaction in aqueous solutions.

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Answer: Copper

Explanation:

Just took it on Edgen

Answer:

copper

Explanation:

Answer:

Mutualism

Explanation:

In Mutualism, both parties benefit.

Increasing temperature increases the reaction rate by increasing the speed of particles. Although increasing concentration and increasing surface area can also speed up a reaction, they do so by increasing the probability of collisions, not particle speed.

The three factors you have listed, namely, increasing concentration, increasing temperature, and increasing surface area, are indeed factors that can increase the rate of a chemical reaction. However, if we're specifically looking at the factor that increases the reaction rate by increasing the particle speed, then the answer would be increasing temperature.

Increasing the temperature causes particles to move faster, and because they're moving faster, they're more likely to collide with each other and react.

On the other hand, increasing concentration increases the number of reactant particles in a given volume, hence, increasing the chance of collisions. Whereas, increasing the surface area of solid reactants increases the area available for collisions to occur. Both will result in a higher rate of reaction, but not by specifically increasing particle speed.

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It depends on whether the system is endothermic or exothermic. If it is endothermic, then adding heat to the system will cause the equilibrium to shift right. Additionally, the k value will increase. Likewise, if the reaction is exothermic, adding heat will cause the equilibrium to shift left. Increasing temperature in an exothermic reaction cause k to decrease.

Le Châtelier's principle explains how a system at equilibrium responds to added heat by shifting to consume the heat, helping predict changes in a chemical equilibrium due to temperature disturbances.

Le Châtelier's principle states that if heat is added to a system at equilibrium, the system will shift to consume the heat. For example, in a liquid-vapor equilibrium, adding heat will cause the system to convert liquid to vapor, increasing the equilibrium vapor pressure.

When a system at equilibrium is disturbed by a change in temperature, it will respond in a way to counteract the disturbance, following Le Châtelier's principle. This principle helps predict how changing conditions like temperature, pressure, or concentration can affect a chemical equilibrium.

Shifting Equilibria: Systems at equilibrium can be disturbed by changes in temperature, concentration, volume, or pressure; Le Châtelier's principle describes how the system will respond to these disturbances to establish a new equilibrium.

Answer:

The final temperature would be 308.7 K or 35.7 °C

Explanation:

Step 1: Data given

The initial pressure = 1200 torr

The pressure is reduced to 760 torr

The initial volume = 0.650 L

The increased volume is 1.1 L

The initial temperature is 15 °C = 288 K

Step 2: Calculate the new temperature

(P1*V1)/T1 = (P2*V2)/T2

⇒with P1 = the initial pressure = 1200 torr

⇒with V1 = the initial volume = 0.650 L

⇒with T1 = initial temperature is 15 °C = 288 K

⇒with P2 = the reduced pressure = 760 torr

⇒with V2 = the increased volume = 1.1 L

⇒with T2 = the final temperature = TO BE DETERMINED

(1200 torr * 0.650 L) / 288 K = (760 torr * 1.1 L) /  T2

T2 = (760 * 1.1 * 288) / (1200 * 0.650)

T2 = 308.7 K

The final temperature would be 308.7 K or 35.7 °C

Answer:

-272.99K = 0.0032°C

Explanation:

Applying (P1V1)/T1 = (P2V2)/T2

(1200×0.65)/288 = (760 × 1.1)/T2

Simplify

T2 = 0.0032°C

Answer:

+125.4 KJmol-1

Explanation:

∆H C4H10(g) = -2877.6kJ/mol

∆H C(s)=-393.5kJ/mol

∆H H2(g) = -285.8

∆H reaction= ∆Hproducts - ∆H reactants

∆H reaction= (-2877.6kJ/mol) - [4(-393.5kJ/mol) +5(-285.8)]

∆H reaction= +125.4 KJmol-1