Given that H2(g)+F2(g)⟶2HF(g)ΔH∘rxn=−546.6 kJ 2H2(g)+O2(g)⟶2H2O(l)ΔH∘rxn=−571.6 kJ calculate the value of ΔH∘rxn for

Answer:

-138.9 kJ/mol

Explanation:

Step 1: Convert 235.8°C to the Kelvin scale

We will use the following expression.

K = °C + 273.15 = 235.8°C + 273.15 = 509.0 K

Step 2: Calculate the standard enthalpy of reaction (ΔH°)

We will use the following expression.

ΔG° = ΔH° - T.ΔS°

ΔH° = ΔG° / T.ΔS°

ΔH° = (-936.92kJ/mol) / 509.0K × 0.51379 kJ/mol.K

ΔH° = -3.583 kJ (for 1 mole of balanced reaction)

Step 3: Convert -9.9°C to the Kelvin scale

K = °C + 273.15 = -9.9°C + 273.15 = 263.3 K

Step 4: Calculate ΔG° at 263.3 K

ΔG° = ΔH° - T.ΔS°

ΔG° = -3.583 kJ/mol - 263.3 K × 0.51379 kJ/mol.K

ΔG° = -138.9 kJ/mol

Answer:

I hope it works

Explanation:

As we know that

w=m*g

given m=0.145 , g=9.8

hence we get

w= (9.8)*(0.145)

w=1.421 m/sec 2

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Answer:

6H20 represents six molecules of water

Answer:

6H20 represents six molecules of water

Explanation:

Answer:

a. Moles in the vessel = 1.85 moles of the gas

b. 1.11x10²⁴ molecules are in the vessel

Explanation:

a.It is possible to determine moles of a gas using the general law of gases:

PV = nRT

Where P is pressure: 5.00atm; V is volume = 9.00L; R is gas constant: 0.082atmL/molK; T is absolute temperature: 273.15K +24.0 = 297.15K

Computing the values:

PV / RT = n

5.00atm* 9.00L / 0.082atmL/molK*297.15K = n

b. With Avogadro's number we can convert moles of any compound to molecules thus:

Avogadro's number = 6.022x10²³ molecules / mole

1.85moles ₓ (6.022x10²³ molecules / mole) =

Answer:

0.327 M

Explanation:

Step 1: Write the balanced equation

2 NH₃(g) ⇄ N₂(g) + 3H₂(g)

Step 2: Make an ICE chart

        2 NH₃(g) ⇄ N₂(g) + 3 H₂(g)

I              x             0            0

C          -2y            +y         +3y

E         x-2y             y           3y

Step 3: Find the value of y

The concentration of N₂ at equilibrium is 0.0161 M. Then,

y = 0.0161

Step 4: Find the value of x

The concentration of NH₃ at equilibrium is 0.295 M. Then,

x-2y = 0.295

x-2(0.0161) = 0.295

x = 0.327

Answer:

the volume of the titrant used

Explanation:

Acid-base titrations are usually depicted on special graphs referred to as titration curve. A titration curve is a graph that contains a plot of the volume of the titrant as the independent variable and the pH of the system as the dependent variable.

Hence, a titration curve is a graphical plot showing the pH of the analyte solution plotted against the volume of the titrant as the reaction is in progress. The titration curve is drawn by plotting data obtained during a titration, that is, volume of the titrant added (plotted on the x-axis) and pH of the system (plotted on the y-axis).

Answer:

1.543 pounds = 700 grams

Answer:

Kp=1.68×10⁴∆1.7×10⁴

Kc=1.06∆1.1

Explanation:

Value of Kp at 227°C is 2.86×10² and value of Kc at 1000 K is 1.56.

Kp and Kc are related by the formula Kp=Kc(RT).For part A , Kp is calculated as,

Kp=6.9×10⁵×8.314×500=28.683×10² and for part B Kc is calculated as,

Kc=1.3×10[tex]^-2[/tex]/(8.314×1000)=1.56

Kc and Kp are equilibrium constants of a mixture of ideal gases. Kp is equilibrium constant when concentrations at equilibrium are in atmospheric pressure and Kc is equilibrium constant when concentrations are in molarity. The relation is only valid for gaseous mixtures. The relation between these two parameters is obtained through ideal gas equation.

Kc and Kp of reaction change with temperature of reaction but remain unaffected by change in concentration , pressure and presence of catalyst.

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Answer:

The compound contains a o molecular orbital formed by the overlap of one carbon sp2 hybrid orbital and one hydrogen sp3 hybrid orbital.

Explanation:

Molecular orbital is function which describes wave like behavior of an electron in a molecule. The molecular orbital theory describes the electronic structure of molecule using quantum mechanics. Electrons are not assigned to individual bonds between atoms. The compound contains sp2 hybrid orbial which is polar C - CI bond.

Answer:

b. the amount of heat given off or absorbed

Explanation:

Hello,

In this case, we should take into account a formal definition of enthalpy change such as an energetic change that occurs in a system when matter is transformed by a given chemical reaction from reactants to products. Thus, such energetic change is macroscopically exhibited and it is related with either a temperature increase or decrease; it means that if a reaction exhibits a temperature increase, we say that heat was given off and if the temperature exhibits a decrease, we say that heat is absorbed. For that reason, answer is b. the amount of heat given off or absorbed.

Regards.

Answer:

The boy must swim at an angle of 59°northwest to get to a position directly opposite his starting point.

Explanation:

To get to a point directly opposite his starting point, the boy must travel at an angle x, in a direction northwest of his starting point. The speed of the boy and the speed of the river current forms a right-angled triangle with an an opposite side of 1.8 m/a and a hypotenuse of 2.1 m/a having an angle x.

Sin x = opp/ hyp

Sin x = 1.8/2.1

x = sin⁻¹ (1.8/2.10

x = 58.99

x = 59°

Therefore, the boy must swim at an angle of 59° in the northwesterly direction to get to a position directly opposite his starting point.

Explanation:

Answer:

The pH of the solution will be 3

Explanation:

The strength of acids is determined by their ability to dissociate into ions in aqueous solution. A strong acid is any compound capable of completely and irreversibly releasing protons or hydrogen ions, H⁺. That is, an acid is said to be strong if it is fully dissociated into hydrogen ions and anions in solution.

Being pH=- log [H⁺] or pH= - log [H₃O⁺] and being a strong acid, all the HClO₃ dissociates:

HClO₄      +    H₂O        →      H₃O⁺      +      ClO₄-  

So: [HCLO₄]= [H₃O⁺]

The molar concentration is:

[tex]molar concentration=\frac{number of moles of solute}{volume solution}[/tex]

The molar mass of HClO₄ being 100 g / mole, then if 100 grams of the compound are present in 1 mole, 0.025 grams in how many moles are present?

[tex]moles of HClO_{4} =\frac{0.025 grams*1 mole}{100 grams}[/tex]

moles of HClO₄= 0.00025

Then:

[tex][HClO_{4}]=\frac{0.00025 moles}{0.25 L}[/tex]

[tex][HClO_{4}]=0.001 \frac{ moles}{ L}[/tex]

Being [HCLO₄]= [H₃O⁺]:

pH= - log 0.001

pH= 3

The pH of the solution will be 3

Answer:

(R)-but-3-en-2-ylbenzene

Explanation:

In this reaction, we have a very strong base (sodium ethoxide). This base, will remove a hydrogen producing a double bond. We know that the reaction occurs through an E2 mechanism, therefore, the hydrogen that is removed must have an angle of 180º with respect to the leaving group (the "OH"). This is known as the anti-periplanar configuration.

The hydrogen that has this configuration is the one that placed with the dashed bond (red hydrogen). In such a way, that the base will remove this hydrogen, the "OH" will leave the molecule and a double bond will be formed between the methyl and the carbon that was previously attached to the "OH", producing the molecule (R) -but-3- en-2-ylbenzene.

See figure 1

I hope it helps!

Answer:

A

Explanation:

The lithosphere represents the layer of hardened/solid rock that makes up the hard part of the earth, including the brittle upper portion of the mantle and the crust. The lithosphere is broken into pieces that are referred to as plates. The pieces move to and away from each other in a process known as plate tectonics. The movement of plates accounts for the global locations of volcanoes, earthquakes, and mountain ranges.

The lithosphere is made of largely of inorganic materials known as silicates. The weathering of the solid rocks together with the interaction of living organisms gives rise to soil with an appreciable amount of organic materials.

The correct option is, therefore A.

Answer:

pH of the buffer is 3.75

Explanation:

It is possible to find pH of a buffer using Hendersson-Hasselbalch equation:

pH = pKa + log [A⁻] / [HA]

Where [A⁻] is molar concentration of the conjugate base and [HA] concentration of the weak acid

In the lactic buffer, pKa = 3.86. Lactic acid is the weak acid and its conjugate base is tha lactate salt. H-H equation for this buffer is:

pH = 3.86 + log [Lactate] / [Lactic acid]

Replacing with the concentrations of the problem:

pH = 3.86 + log [0.10M] / [0.13M]

pH = 3.75

Answer:

[ClO] = 3.48×10¯⁹ M.

Explanation:

The following data were obtained from the question:

Equilibrium constant (Kc) = 4.96×10¹¹

Concentration of Cl2O2, [Cl2O2] = 6x10¯⁶ M.

Concentration of ClO, [ClO] =.?

The equation for the reaction is given below:

2ClO(g) ⇌ Cl2O2(g)

The equilibrium constant for a reaction is simply defined as the ratio of the concentration of product raised to their coefficient to the concentration of the reactant raised to their coefficient.

The equilibrium constant, Kc for the reaction is given by:

Kc = [Cl2O2] / [ClO]²

Thus, we can calculate the concentration of ClO, [ClO] as follow:

Kc = [Cl2O2] / [ClO]²

4.96×10¹¹ = 6x10¯⁶ / [ClO]²

Cross multiply

4.96×10¹¹ × [ClO]² = 6x10¯⁶

Divide both side by 4.96×10¹¹

[ClO]² = 6x10¯⁶ / 4.96×10¹¹

[ClO]² = 1.21×10¯¹⁷

Take the square root of both side

[ClO] = √ (1.21×10¯¹⁷)

[ClO] = 3.48×10¯⁹ M

Therefore, the concentration of ClO, [ClO] is 3.48×10¯⁹ M.

Answer:

Explanation:

we know that

ΔH=m C ΔT

where ΔH is the change in enthalpy (j)

m is the mass of the given substance which is water in this case

ΔT IS the change in temperature and c is the specific heat constant  

we know that given mass=2.9 g

ΔT=T2-T1 =98.9 °C-23.9°C=75°C

specific heat constant for water is 4.18 j/g°C

therefore ΔH=2.9 g*4.18 j/g°C*75°C

ΔH=909.15 j

Answer:

The ΔG° is 29 kJ and the reaction is favored towards reactant.

Explanation:

Based on the given information, the ΔH°rxn or enthalpy change is 41.2 kJ, the ΔS°rxn or change in entropy is 42.1 J/K or 42.1 * 10⁻³ kJ/K. The temperature given is 289 K. Now the Gibbs Free energy change can be calculated by using the formula,  

ΔG° = ΔH°rxn - TΔS°rxn

= 41.2 kJ - 289 K × 42.1 × 10⁻³ kJ/K

= 41.2 kJ - 12.2 kJ

= 29 kJ

As ΔG° of the reaction is positive, therefore, the reaction is favored towards reactant.  

Answer:

The length the divider is to  equilibrium from Part A = 1.30 m and from Part B = 3.70 m

Explanation:

Given that:

A rectangular cube with 3.2 m breadth, 1.2 m height and 5 m in length is splitted into two parts.

The diagrammatic expression for the above statement can be found in the attached diagram below.

The container has a movable airtight divider that divides its length as necessary.

Part A has 58 moles of gas

Part B has 165 moles of a gas.

Thus, the movable airtight divider will stop at a length where the pressure on it is equal on both sides.

i.e

[tex]\mathtt{P = P_A = P_B}[/tex]

Using the ideal gas equation,

PV = nRT

where, P,R,and  T are constant.

Then :

[tex]\mathsf{\dfrac{V_A}{n_A}= \dfrac{V_B}{n_B}}[/tex]

[tex]\mathsf{\dfrac{L_A \times B \times H}{n_A}= \dfrac{L_B \times B \times H}{n_B}}[/tex] --- (1)

since Volume of a cube = L × B × H

From the question; the L = 5m

i,e

[tex]\mathsf{L_A +L_B}[/tex] = 5

[tex]\mathsf{L_A = 5 - L_B}[/tex]

From equation (1) , we divide both sides by (B × H)

Then :

[tex]\mathsf{\dfrac{L_A }{n_A}= \dfrac{L_B }{n_B}}[/tex]

[tex]\mathsf{\dfrac{5-L_B}{58}= \dfrac{L_B }{165}}[/tex]

By cross multiplying; we have:

165 ( 5 - [tex]\mathsf{L_B}[/tex] )  = 58 (

825 - 165[tex]\mathsf{L_B}[/tex]  = 58

825 = 165[tex]\mathsf{L_B}[/tex] +58

825 = 223[tex]\mathsf{L_B}[/tex]

[tex]\mathsf{L_B}[/tex] = 825/223

[tex]\mathsf{L_B}[/tex]  = 3.70 m

[tex]\mathsf{L_A = 5 - L_B}[/tex]

[tex]\mathsf{L_A = 5 - 3.70}[/tex]

[tex]\mathsf{ L_A}[/tex] = 1.30 m

The length the divider is to  equilibrium from Part A = 1.30 m and from Part B = 3.70 m

Answer:

SCN- is a weak field ligand while CN- is a strong field ligand

Explanation:

The spectrochemical series is an arrangement of ligands according to their magnitude of crystal field splitting. Ligands that cause only a small degree of crystal field splitting are called weak field ligands while ligands that cause large crystal field splitting are called strong field ligands.

Strong field ligands often lead to the formation of low spin complexes with the least number of unpaired electrons while high spin complexes are formed by weak field ligands.

CN- is a strong field ligand as it lies towards the right hand side of the spectrochemical series.

SCN- is a weak field ligand hence it forms a high spin complex having the maximum number of unpaired electrons for Fe^3+, hence the answer.

SCN⁻ lies in the lower (weak field) region of the spectrochemical series while CN⁻ lies in the higher (stronger field) region.

CN⁻ is a strong field ligand with a large splitting constant, and it is high up in the spectrochemical series.

Conversely, SCN⁻ is a weak field ligand with a low splitting constant, and it is lower in the spectrochemical series.

Hence, SCN⁻ lies in the lower (weak field) region of the spectrochemical series while CN⁻ lies in the higher (stronger field) region.

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Answer:

a. MnO₄⁻ + 8H⁺ + 5Fe²⁺ → 5Fe³⁺ + Mn²⁺ + 4H₂O

b. 18.17% of Fe in the sample

Explanation:

a. In the reaction, Fe²⁺ is oxidized to Fe³⁺ and permanganate, MnO₄⁺ reduced to Mn²⁺, thus:

Fe²⁺ → Fe³⁺ + 1e⁻

MnO₄⁻ + 5e⁻ + 8H⁺ → Mn²⁺ + 4H₂O

5 times the iron and suming the manganese reaction:

MnO₄⁻ + 5e⁻ + 8H⁺ + 5Fe²⁺ → 5Fe³⁺ + 5e⁻ + Mn²⁺ + 4H₂O

b. Moles of permanganate in the titration are:

0.03942L × (0.0281 moles / L) = 1.108x10⁻³ moles of MnO₄⁻

Based on the reaction, 1 mole of permanganate reacts with 5 moles of iron, if 1.108x10⁻³ moles of MnO₄⁻ reacts, moles of iron are:

1.108x10⁻³ moles of MnO₄⁻ × (5 moles Fe²⁺ / 1 mole MnO₄⁻) =

4.431x10⁻³ moles of Fe²⁺. Molar mass of Fe is 55.845g/mol. 4.431x10⁻³ moles of Fe²⁺ are:

4.431x10⁻³ moles of Fe²⁺ ₓ (55.845g / mol) =

Percent mass is:

0.2474g Fe / 1.362g sample ₓ 100 =

The mass percent of iron in the sample is 22.6%.

The net ionic equation of the reaction is;

5Fe^2+(aq) + 8H^+(aq) + MnO4^-   -----> 5Fe^3+(aq) + Mn^2+(aq) + 4H2O(l)

Number of moles of MnO4^-  = 39.42/1000 L × 0.0281 M = 0.0011 moles

If 5 moles of Fe^2+ reacts with 1 mole of MnO4^-

x moles of Fe^2+ reacts with 0.0011 moles

x =  5 moles × 0.0011 moles/1 mole

x = 0.0055 moles

Mass of Fe^2+ =  0.0055 moles × 56 g/mol = 0.308 g

Mass percent of iron = 0.308 g/ 1.362 g × 100/1

= 22.6%

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Answer:

- you have to do maths in all 3

- atoms make up everything even parts of a cel and theyre studied in chem and physics

- chemistry is used in biology by finding out what different substances are eg cytoplasm in a cell

Answer:

THE EMPIRICAL FORMULA OF THE COMPOUND IS NF2

THE MOLECULAR FORMULA OF THE COMPOUND IS N2F4

Explanation:

To calculate the empirical formula for the compound, we:

1. Write out the percentage weight of each elements

N = 26.94%

F = 73.06 %

2. Divide each by its atomic mass

( N= 14, F = 19)

N = 26.94 / 14 = 1.924

F = 73.06 / 19 = 3.845

3. Divide each by the smaller of the values

N = 1.924 / 1.924 = 1

F = 3.845 / 1.924 = 1,998

4. Round up to a whole number and write the empirical formula

N= 1

F = 2

So the empirical formula of the compound is N F2

To calculate the molecular formula, we:

(N F2 )n = molecular weight

( 14 + 19*2) n = 104.02

52 n = 104.02

n = 2.000

The molecular formula of the compound will be:

(N F2)2 = N2F4

In conclusion, the empirical formula of the compound is NF2 and the molecular formula of the compound is N2F4

Answer:

a. Sodium cyclopentanecarboxylate

b. No reaction

Explanation:

In this case, in the cyclopentanecarboxylic acid we have a carboxylic acid functional group. Therefore we have an "acid". The acids by definition have the ability to produce hydronium ions ([tex]H^+[/tex]).

With this in mind, for molecule a. we will have an acid-base reaction, because NaOH is a base. When we put together an acid and a base we will have as products a salt and water. In this case, the products are  Sodium cyclopentanecarboxylate (the salt) and water.

For the second molecule, we have the hydronium ion  ([tex]H^+[/tex]). This ion can not react with an acid. Because, the acid will produce the hydronium ion also, so a reaction between these compounds is not possible.

See figure 1

I hope it helps!

Answer:

Explanation:

a )

CH₃CH₂CH₂CH₂CH₂Br + KOH   ⇒ CH₃CH₂CH₂CH₂CH₂OH

CH₃CH₂CH₂CH₂CH₂OH  + acidic potassium dichromate ⇒  CH₃CH₂CH₂CH₂COOH

b )

CH₃CH₂CH₂CH₂CH₂Br + KCN ⇒ CH₃CH₂CH₂CH₂CH₂CN  Hydrolysis ⇒ CH₃CH₂CH₂CH₂CH₂COOH .

c )

CH₃CH₂CH₂CH₂CH₂Br + KOH   ⇒ CH₃CH₂CH₂CH₂CH₂OH

CH₃CH₂CH₂CH₂CH₂OH  + acidic potassium dichromate ⇒  CH₃CH₂CH₂CH₂COOH + SOCl₂ ( thionyl  chloride ) ⇒ CH₃CH₂CH₂CH₂COCl

d )

CH₃CH₂CH₂CH₂CH₂Br + KCN ⇒ CH₃CH₂CH₂CH₂CH₂CN  Hydrolysis ⇒ CH₃CH₂CH₂CH₂CH₂COOH + PCC ( NH₃ ) ⇒ CH₃CH₂CH₂CH₂CH₂CONH₂

e )

CH₃CH₂CH₂CH₂CH₂Br + KCN ⇒ CH₃CH₂CH₂CH₂CH₂CN  Hydrolysis ⇒ CH₃CH₂CH₂CH₂CH₂COOH + C₂H₅OH ( Ethyl alcohol + H⁺ )⇒  

CH₃CH₂CH₂CH₂CH₂COOC₂H₅ ( ethyl hexanoate )

Answer:

2200 L

Explanation:

Ideal gas law:

PV = nRT,

where P is absolute pressure,

V is volume,

n is number of moles,

R is universal gas constant,

and T is absolute temperature.

The initial number of moles is:

(110 atm) (80 L) = n (0.0821 L atm / K / mol) (30 + 273.15) K

n = 353.58 mol

After some gas is removed, the number of moles remaining is:

(80 atm) (80 L) = n (0.0821 L atm / K / mol) (30 + 273.15) K

n = 257.15 mol

The amount of gas removed is therefore:

n = 353.58 mol − 257.15 mol

n = 92.43 mol

At normal conditions, the volume of this gas is:

PV = nRT

(1 atm) V = (92.43 mol) (0.0821 L atm / K / mol) (273.15 K)

V = 2162.5 L

Rounded, the volume is approximately 2200 liters.

Explanation:

using boyles law

p1v1=p2v2

735 x 1.76 = 700 x V2

1293.6 = 700 x V2

V2 = 1293.6/700

V2 = 1.85L

Answer:

PLEASE SHOW ME THE ELEMENTS OR I WOULD ENLIST ALL THE ELEMENTS.

Explanation:

Group 6A (or VIA) of the periodic table are the chalcogens: the nonmetals oxygen (O), sulfur (S), and selenium (Se), the metalloid tellurium (Te), and the metal polonium (Po)