If a jet’s cruising altitude is 32,200ft(to three significant figures),the distance in km is :(1 mile=1.61km;1 mile=5280 ft)

Answer:

The given blanks can be filled with below, below, larger, larger, larger, larger and smaller.

Explanation:

In the periodic table, rubidium comes below the potassium, and iodine comes below bromine. Therefore, it can be said that the ion of rubidium is larger in comparison to potassium ion, and similarly the ion of iodine is larger in comparison to the ion of bromine.  

When the atomic radius is larger it signifies that the distance in between the ion of iodine and the ion of rubidium is larger in comparison to that between the ion of potassium and the ion of bromine. Thus, smaller energy is associated with the interaction between iodine and rubidium, and potassium bromide's lattice energy is more exothermic.  

Answer:

A- 25.9 kJ

Explanation:

ΔH of formation is defined as the amount of energy that is involved in the formation of 1 mole of substance.

ΔH of rust is -826kJ/mol, that means when 1 mole of rust is formed, there are released -826kJ.

Moles of 5.00g of Fe₂O₃ (Molar mass: 159.69g/mol) are:

5.00g ₓ (1 mole / 159.69g) = 0.0313 moles of Fe₂O₃.

If 1 mole release -826kJ, 0.0313 moles release:

0.0313 moles ₓ (-826kJ / 1 mole) = -25.9kJ

Thus, heat involved is:

Answer: The molecules in the thermometer's liquid spread apart.

Explanation:

Mercury is the only metal that remains liquid at room temperature. It has a high coefficient of expansion therefore the its level rises when exposed to a temperature range. It can detect a slight change in temperature. It has a high  boiling point.

When the thermometer is placed in the water to measure the temperature, the molecules of thermometer liquid that is mercury only will spread due to high coefficient of expansion. This can be seen as rise in temperature.

Answer:

B

Explanation:

Just did the test

Answer:

A. 30

Explanation:

Retinol is the chemical form of Vitamin A. It has a chemical formula of C20H30O.

It is processed when retinyl palmitate is broken down in the small intestine. Retinol helps in the proper regulation of eye cells hence a vital component in ensuring good eye sight.

It also helps in the neutralization of free radicals in the body and acts as an antioxidant which prevents cells of the body from ageing.

Answer:

1.  2.28 g

2. 0.82 g

3. 1.35 g

4. 36 %

5. 59 %

6. 2.17 g

7. 95 %

Explanation:

Hello,

1. In this case, the mass of the unknown mixture is obtained by subtracting the mass of the dish plus sample and the mass of the dish:

m = 26.57 g- 24.29 g = 2.28 g

2. In this case, the mass of the NaCl recovered is obtained by subtracting the mass of the dish plus NaCl and the mass of the dish:

m = 68.66 g- 67.84 g = 0.82 g

3. In this case, the mass of the sand recovered is obtained by subtracting the mass of the filter paper plus sand and the mass of the filter paper:

m = 37.69 g- 36.34 g = 1.35 g

4. The percentage of NaCl is computed by considering its mass and the mass of the unknown mixture:

% NaCl = 0.82 g / 2.28 g * 100 % = 36 %

5. The percentage of sand is computed by considering its mass and the mass of the unknown mixture:

% sand = 1.35 g / 2.28 g * 100 % = 59 %

6. Here,we have to add the mass of NaCl and sand:

m = 0.82 g + 1.35 g = 2.17 g

7. Finally, the percent recovery is obtained by diving the total recovered mass by the total obtained mass of the mixture:

% recovery = 2.17 g / 2.28 g * 100 % = 95 %

Best regards.

Answer:

CaSO4

Explanation:

Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO4 and related hydrates.

Answer:

neutral atoms coming together to share electrons

Answer:

a

Explanation:

neutral atoms coming together to share electrons

Answer:

3) 310 g/mol

Explanation:

Hello,

In this case, for calcium carbonate, we are able to compute its gram-formula mass by considering the atomic mass of each element composing it and their subscripts as shown below:

[tex]M=3*m_{Ca}+2*m_P+4*2*m_O\\[/tex]

Thus, we compute:

[tex]M=3*40g/mol+2*31g/mol+4*2*16g/mol\\\\M=310g/mol[/tex]

Hence answer is 3) 310 g/mol . Remember this is also known as the molar mass of the mentioned compound.

Best regards.

Answer:

Explanation:

The objective here is to prepare  1 liter of LB + Kan (100 μg/ml final concentration) + Amp (50 μg /ml final concentration) liquid media.

Given that :

the Stock concentration of Amp: 100 mg/ml (since 1 mg/ml = 1000 μg/ml)

it is required that we convert stock concentration in  μg/ml since 100 mg/ml = 100000  μg/ml

However, using formula C₁V₁=C₂V₂ (Ampicilin),

where:

C₁ = 100000 μg/ml,

V₁=?,

C₂= 50  μg/ml,

V₂=1000 ml

100000 μg/ml × V₁ = 50  μg/ml × 1000 ml

V₁ =  50  μg/ml × 1000 ml/100000 μg/ml

V₁ =   0.5 ml

Given that:

the Stock concentration of Kan: 25 mg/ml (since 1 mg/ml = 1000 μg/ml)

it is required that we convert stock concentration in  μg/ml , 25 mg/ml = 25000 μg/ml

Now by using formula C₁V₁=C₂V₂ (Kanamycin),

C₁ = 25000 μg/ml,

V₁=?,

C₂= 100  μg/ml,

V₂=1000 ml

25000 μg/ml × V₁ = 100  μg/ml × 1000 ml

V₁ =  100  μg/ml × 1000 ml/25000 μg/ml

V₁ =   4 ml

Thus; in 1 lite of Lb+ Kan+Amp preparation;

0.5 ml of Amp & 4 ml of kanamycin is used for their stock preparation.

Finally;

Sterilization step should be carried out in flask (Clean dry glass wares) for media in an autoclave, the container size should be twice the volume of media which is prepared.

Answer: 8 (feet)

Explanation:

24 inches = 2 feet

48 inches = 4 feet

12 inches = 1 foot

To find volume you do Base * Width * Height

2*4*1 = 8

Hope this helps!

The correct answer is  8 (feet).

How to calculate ?

Therefore, 2*4*1 = 8

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Answer:0.30 m KI ---- A. Highest boiling point

0.19 m Mg(CH3COO)2 ---- B. Second highest boiling point

0.53 m Glucose(nonelectrolyte) ---- Third highest boiling point-C

0.13 m FeCl3---- Lowest boiling point-D

Explanation:

Using the  boilng point elevation formula

ΔTb=m* kb *i

where m= molality

kb= elevated boiling point constant( here kb values will be same for all soluton)

i= vant hoff factor = number of ions present in a solution

Using the  number of ions and molarity present in a solution as a collagative property, since kb is constant, we can determine which of the species has the highest boiling point.

1.) 0.13 m FeCl3= Fe³⁻  + Cl⁻

        i=4

ΔTb=m* kb* i= molarity x number of ionsx Kb= 0.13 x 4= 0.52kb

2) 0.19 m Mg(CH3COO)2 = Mg²⁺ + CH₃COO⁻

i= 3

ΔTb=m* kb* i= molarity x number of ions= 0.19 x 3= 0.57kb

3. 0.30 m KI = K⁺  + I⁻

i= 2

ΔTb=m *kb *= imolarity x number of ions xKb= 0.30x 2= 0.60kb

4. 0.53 m Glucose(nonelectrolyte) =

i= 1 for nonelectroytes

ΔTb=m* kb* i = molarity x number of ionsx Kb= 0.53 x 1= 0.53Kb

therefore,

0.30 m KI ---- A. Highest boiling point

0.19 m Mg(CH3COO)2 ---- B. Second highest boiling point

0.53 m Glucose(nonelectrolyte) ---- Third highest boiling point

0.13 m FeCl3---- Lowest boiling point

Answer:

The reaction is not in equilibrium and  must move in a backward manner i.e towards the reactant so that it will attain equilibrium

Explanation:

The complete question is as follows;

Consider the following reaction where Kc = 2.90×10-2 at 1150 K: 2 SO3 (g) 2 SO2 (g) + O2 (g) A reaction mixture was found to contain 4.71×10-2 moles of SO3 (g), 5.00×10-2 moles of SO2 (g), and 4.53×10-2 moles of O2 (g), in a 1.00 liter container.

Is the reaction at equilibrium? If not, what direction must it run in order to reach equilibrium? The reaction quotient, Qc, equals . The reaction A. must run in the forward direction to reach equilibrium. B. must run in the reverse direction to reach equilibrium. C. is at equilibrium.

Solution

The first thing to do here is to calculate the pressure of each of the gases. This would be useful in the equilibrium calculations. We calculate this by dividing the respective number of moles by the volume of the container.

Now, since the volume of the container is 1L, then the number of moles will be equal to the pressure of the gaseous substances, although units will be different.

So, [SO3] = 4.71 * 10^-2 mol/L

[SO2] = 5.00 * 10^-2 mol/L

[O2] = 4.53 * 10^-2 mol/L

The equation of the reaction is as follows;

[tex]2SO_{3(g)}[/tex]    ⇆    [tex]2SO_{2(g)}[/tex]   +    [tex]O_{2(g)}[/tex]

We proceed to calculate the reaction quotient Qc

Mathematically Qc for this reaction = [[tex]SO_{2}[/tex]]^2 × [[tex]O_{2}[/tex]]/ [[tex]SO_{3}[/tex]]^2

Qc = {(5 * 10^-2)^2 * (4.53 * 10^-2)}/ (4.71 * 10^-2)^2 = 5.11 × 10^-2 mol/L

Now, we are given that the value of Kc = 2.9 * 10^-2 which is less than Qc

Since Kc < Qc, the backward reaction is favored.

Now to the question;

The reaction is not in equilibrium and  must move in a backward manner i.e towards the reactant  so that it will attain equilibrium

Answer:

The answer is 5.

Answer:

The type of salt to be added to the water is not known from the question but no worries, I will try to give you the step by step procedure to answer any type of question similar to this.

To answer this question, we should know some facts.

1. the molar freezing point depression constant of water (Kf) = 1.86 K kg/mol

2. the molar mass of the salt if NaCl = 58.5 g/mol ; KCl = 74.5 g/mol

3. since the salt can dissociate if NaCl or KCl into two ions, the Van't Hoff factor ( i )= 2

Note that: the change in freezing point, molarity, deepression constant and van't Hoff factor are related by this formula;

                ΔTf = i Kf m

So lets take NaCl as the salt:

Molar mass = 58.5 g/mol

Van't Hoff factor = 2

1. calculate the number of moles

So we can calculate the molarity of the salt NaCl from the formula;

m = ΔTf / i Kf

m = 5 / 2 * 1.86

m = 5 / 3.72

m = 1.344 mol/kg

2. calculate the number of moles of the salt required

Next is to multiply the molarity by the mass of water. Density of water = 1kg/L

number of moles = 1.344 mol/kg * 1 Kg/L * 1 kg water

number of moles = 1.344 moles.

3. calculate the mass of the salt.

numner of moles = mass / molar mass

mass = number of moles * molar mass

mass = 1.344 * 58.5

mass = 78.624 g of NaCl salt.

You can follow these steps to solve for the type of salt you are given in the question.

Answer:

 4.90  moles of  [tex]Mg(ClO_4)_2[/tex]   will produce  (9.8) moles of  [tex]Cl^{-}[/tex] ,

                                                    (4.90) moles of [tex]Mg^{2+}[/tex] and

                                                    (39.2) moles of  [tex]O^{2-}[/tex]

Explanation:

From the question we are told that

  The number of moles of  is  [tex]n = 4.90 \ mols[/tex]

The formation reaction of [tex]Mg(ClO_4)_2[/tex]  is

             [tex]Mg^{2+} + 2 Cl^{-} + 8O^{2+} \to Mg(ClO_4)_2[/tex]  

From the reaction we see that

   1 mole of  [tex]Mg(ClO_4)_2[/tex]  is formed by 2 moles of [tex]Cl^{-}[/tex] 1 mole of  [tex]Mg^{2+}[/tex] and 4  [tex]O^{2-}[/tex]

 This implies that

   4.90  moles of  [tex]Mg(ClO_4)_2[/tex]   will produce  (2 * 4.90) moles of  [tex]Cl^{-}[/tex] ,

                                                    (1 * 4.90) moles of [tex]Mg^{2+}[/tex] and

                                                    (8 * 4.90) moles of  [tex]O^{2-}[/tex]

So

  4.90  moles of  [tex]Mg(ClO_4)_2[/tex]   will produce  (9.8) moles of  [tex]Cl^{-}[/tex] ,

                                                    (4.90) moles of [tex]Mg^{2+}[/tex] and

                                                    (39.2) moles of  [tex]O^{2-}[/tex]

Answer:

- [tex]n_{Mg}=4.90molMg[/tex]

- [tex]n_{Cl}=9.6molCl[/tex]

- [tex]n_{O}=38.4molO[/tex]

Explanation:

Hello,

In this case, for the given 4.90 moles of magnesium perchlorate, we can compute the moles of each atom by identifying the subscript each atom has in the molecule as shown below:

- Moles of magnesium atoms: here, one mole of magnesium perchlorate has only one mole of magnesium atom (subscript is one), this the moles of magnesium atoms are also 4.90 moles.

- Moles of chlorine atoms: here, one mole of magnesium perchlorate has two moles of chlorine atoms as it has a two out of the parenthesis enclosing the perchlorate anion, thus, we have:

[tex]n_{Cl}=4.80molMg(ClO_4)_2*\frac{2molCl}{1molMg(ClO_4)_2} =9.6molCl[/tex]

- Moles of oxygen atoms: here, one mole of magnesium perchlorate has eight moles of oxygen atoms as it has a four in the oxygen subscript and a two out of the parenthesis enclosing the perchlorate anion, thus, we have:

[tex]n_{O}=4.80molMg(ClO_4)_2*\frac{8molO}{1molMg(ClO_4)_2} =38.4molO[/tex]

Best regards.

Answer:

Ozone has dipole moments because its molecular chemical structure is no linear.

Explanation:

This molecular form refers to the geometry of said gas, which is potentially toxic and dangerous.

This non-linear geometric shape is what makes it have dipolarity.

Answer:

A

Explanation:

They are all found in the reactants side

Answer:

Canonical structures of a chemical specie explain its observed properties from a valence bond theory perspective.

Explanation:

Resonance is a valence bond concept introduced by Linus Pauling to explain the observed properties of certain chemical species such as bond lengths, bond angles, bond order , etc.

There are certain chemical species for which a single chemical structure does not suffice in explaining its observed properties. For instance, the bond order in CO3^2- is about 1.33. Its bond length, shows that the C-O bond present in CO3^2- is neither a pure C-O single bond nor a pure C-O double bond. Hence the structure of CO3^2- is 'somewhere in between' three contributing canonical structures as shown in the image attached to this answer. The resonance structures of NO3^- are also shown.

Answer:

Element and compounds are the pure substances but mixture is not a pure substance.

Explanation:

Element and compounds are the pure substances in which element comprise of only one atom while compound is formed by the chemical combination of more than one element in a fixed ratio by mass while mixture is also made up of more that one substances but they are combine physically not chemically. Elements, compounds, mixtures are very important because all the materials we used in our daily life are formed from elements, compounds and mixtures.

Answer:

The answer is "Option b"

Explanation:

In this question first we calculates the moles in F-, HF, and in HCL, which can be defined as follows:

Formula:

[tex]\ Number \ of \ moles\ = \ Molarity \times \ Volume \ in \ litter[/tex]

[tex]\ moles \ in\ F- = 0.100 \ M \times 0.0250 L\\\\[/tex]

                     [tex]=\ 0.0025 \ moles[/tex]

[tex]\ moles \ in \ HF \ = 0.126M \times 0.0250 L[/tex]

                       [tex]= 0.00315 \ moles[/tex]

[tex]\ moles \ in \ HCl = 0.0100M \times 0.00500 L[/tex]

                       [tex]= 0.00005 \ moles[/tex]

[tex]\ Reaction: \\\\F - + H+ \rightarrow HF[/tex]

[tex]\Rightarrow \ moles \ in \ F- = 0.0025 \\\\\Rightarrow \ moles \ in \ H+ = 0.00005 \\\\ \Rightarrow \ moles \ in \ HF = 0.00315\\\\ \ total \ moles = 0.00250 -0.0000500 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0.00315 + 0.00005\\\\\ total \ moles =0.00245 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 0.00245[/tex]

[tex]\ total \ volume \ in \ the \ solution = \ V = \ 0.0300 L\\\\ after \ addition \ of \ HCl \ the \ concentration \ of \ F- \ = 0.00245\ moles \div V[/tex]

                                                                                [tex]=\frac{ 0.00245 \ moles }{0.0300L}\\\\= \frac{245 \times 10^4}{300 \times 10^5} \\\\= \frac{245}{3000} \\\\ = 0.0817 M[/tex]

Answer:

(1). Mole fraction = 0.152 for sulfur tetrafluoride gas.

Mole fraction = 0.848 For dinitrogen monoxide gas.

(2). Partial Pressure for dinitrogen monoxide gas = 187 kPa

Partial Pressure for sulfur tetrafluoride gas = 33.4 kpa.

(3). Total Partial Pressure = 220.4 kpa.

Explanation:

So, we are given the following data or parameters or information in the question above;

• Volume of the tank = 5.00L per tank;

• Temperature of the tank = 7.03°C;

• The mass of the content in the tank =

17.7g of dinitrogen monoxide gas and

7.77g of sulfur tetrafluoride gas.

So, we will be making use of the formulae below to calculate the MOLE FRACTION:

Moles, n= mass/molar mass and mole fraction = n(1)/ n(1) + n(2) per each constituents.

Moles, n1 = 17.7g of dinitrogen monoxide gas/ 44 grams per mole. =0.4023 moles.

Moles, n2 = 7.77g of sulfur tetrafluoride gas/ 108.1 grams per mole. = 0.07188 moles.

Total numbers of moles = n1 + n2 = 0.47415 moles

Mole fraction =0.4023 / 0.47415 = 0.848 of dinitrogen monoxide gas.

Mole fraction = 0.07188/0.47415 = 0.152 of sulfur tetrafluoride gas.

PART TWO: CALCULATE THE PARTIAL PRESSURE AND TOTAL PRESSURE BY USING THE FORMULA BELOW;

pressure × volume = number of moles × gas constant, R × temperature.

Pressure = n × R × T/ V.

For dinitrogen monoxide gas. ;

Partial Pressure = 0.4023 × 8.314 × 280.03 / 5 × 10^-3 = 187 kPa.

For sulfur tetrafluoride gas

Partial Pressure = 0.07188 × 8.314 ( × 280.03 / 5 × 10^-3. = 33.4 kpa.

(3). Total pressure = (187 + 33.4)kpa = 220.4 kpa

Answer:

D. Phosphorylation by ATP, which turns the complex off, and dephosphorylation, which turns the complex on.

Explanation:

The pyruvate dehydrogenase complex (PDH) is responsible for the conversion of pyruvate to acetylCoA, the fuel for the citric acid cycle.

The regulation of the activity of PDH is allosterically by the products of the reaction which it catalyses. These products are ATP, acetylCoA and NADH. When their is sufficient fuel available for the needs of the cells in the form of ATP, the complex is turned off by phosphorylation of one of the two subunits of E1 (pyruvate dehydrogenase). This phosphorylation inactivates E1. When the concentration of ATP declines, a specific phosphatase removes the phosphoryl group from E1, thereby activating the complex again.

Answer:

The correct answer is Option A (There is no magnetic flux through the wire loop.)

Explanation:

Magnetic flux measures the entire magnetic field that passes through the wire loop.

The right hand rule can be demonstrated on how magnetic flux is generated through the moving current in the wire loop. The magnetic flux through the wire loop  will decrease as it moves upward through the magnetic field region.

If the direction of the vector area of the wire loop is to the right, and the switch is closed, it will push the magnetic flux to the right which will now be increased due to an equal increase in the current in the wire loop. But, when the switch is open, this will halt the movement of current through the wire loop thus affecting the generation of magnetic field. This would make the magnetic flux to be zero.

The statement related to the magnetic flux is option A i.e. no magnetic flux is there.

It determined the overall magnetic field that should be passed via the looping of the wire. here the right-hand rule represent how the magnetic flux should be created via the movement of the current.

Also, it should be decreased in the case when it should be moved upward. Also, in the case when the direction of the vector area should be right so the switch should be closed.

Therefore, the option A is correct.

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Answer:

THE HEAT OF THIS REACTION PER MOLE OF SUCROSE IS 4868.75 KJ OF HEAT.

Explanation:

To answer this question:

First calculate the total heat given off by sucrose:

         Total energy/ heat = heat capacity * change in temperature

Heat capacity = 7.50 kJ/ °C

Change in temperature = 20.5 °C

Heat = 7.50 kJ * 20.5 °C

Heat = 153.75 kJ of heat.

Next is to calculate the heat of reaction per mole of the sucrose

Equation of the reaction:

               C12H22011 (s) + 12 O2 (g) ---------> 12 CO2 (g) + 11 H20(l)

Since 1 mole of sucrose will be the molar mass of sucrose, then we should calculate the molar mass of sucrose.

Molar mass of sucrose = ( 12* 12 + 1 * 22+ 16*11) g/mol

Molar mass = 342 g/mol of sucrose

Since 10.8 g of sucrose produces 153.75 kJ of heat, 342 g will produces how many joules of heat?

10.8 g of sucrose = 153.75 kJ of heat

342 g of sucrose = ( 342 * 153.75 kJ / 10.8)

= 52 582.5 kJ / 10.8

= 4868.75 kJ of heat

So therefore, 1 mole of sucrose will produce 4868.75 kJ of heat.

Answer:

  98.9%

Explanation:

2 moles of I₂ are required for each mole of Mg, so the reaction is limited by the available I₂. The 3.56 moles of I₂ should react with 1.78 moles of Mg to produce 1.78 moles of MgI₂. Instead, we get 1.76 moles of MgI₂.

The yield is 1.76/1.78 × 100% ≈ 98.876%

The yield is 98.9% of the quantity expected based on available reactants.

Answer:

THE MOLAR MASS OF XCL2 IS 400 g/mol

THE MOLAR MASS OF YCL2 IS 250 g/mol.

Explanation:

We calculate the molar mass of XCL2 and YCL2 by bringing to mind the formula for molar mass when mass and amount or number of moles of the substance is given.

Number of moles = mass / molar mass

Molar mass = mass / number of moles.

For XCL2,

mass = 100 g

number of mole = 0.25 mol

So therefore, molar mass = mass / number of moles

Molar mass = 100 g / 0.25 mol

Molar mass = 400 g/mol.

For YCL2,

mass = 125 g

number of mole = 0.50 mol

Molar mass = 125 g / 0.50 mol

Molar mass = 250 g/mol.

So therefore, the molar mass of XCL2 and YCL2 IS 400 g/mol and 250 g/mol respectively.

Answer:

C6H6<C7H15OH<C6H13OH<C2H5OH​

Explanation:

Organic substances are ordinarily nonpolar. This means that they do not dissolve in water. However, certain homologous series of organic compounds actually dissolve in water because they possess certain functional groups that effectively interact with water via hydrogen bonding.

A typical example of this is alcohol family. All members of this homologous series contain the -OH functional group. This group can effectively interact with water via hydrogen bonding, leading to the dissolution of low molecular weight alcohols in water.

Low molecular weight alcohols are miscible with water in all proportions. This implies that they are highly soluble in water. However, as the size of the alkyl moiety in the alcohol increases, the solubility of the alcohol in water decreases due to less effective interaction of the -OH group with water via hydrogen bonding. This explains the fact that C2H5OH​ is the most soluble alcohol in the list.

C6H6 is insoluble in water since it is purely a hydrocarbon with no -OH group capable of interaction with water via hydrogen bonding.

Answer:

8.09x10⁻⁵M of Fe³⁺

Explanation:

Using Lambert-Beer law, the absorbance of a sample is proportional to its concentration.

In the problem, the Fe³⁺ is reacting with KSCN to produce Fe(SCN)₃ -The red complex-

The concentration of Fe³⁺ in the reference sample is:

4.80x10⁻⁴M Fe³⁺ × (5.0mL / 50.0mL) = 4.80x10⁻⁵M Fe³⁺

Because reference sample was diluted from 5.0mL to 50.0mL.

That means a solution of  4.80x10⁻⁵M Fe³⁺ gives an absorbance of 0.512

Now, as the sample of the lake gives an absorbance of 0.345, its concentration is:

0.345 × (4.80x10⁻⁵M Fe³⁺ / 0.512) = 3.23x10⁻⁵M.  

As the solution was diluted from 20.0mL to 50.0mL, the concentration of Fe³⁺ in Jordan lake is:

3.23x10⁻⁵M Fe³⁺ × (50.0mL / 20.0mL) = 8.09x10⁻⁵M of Fe³⁺

The concentration of  Fe³⁺ in Jordan Lake is = 8.09* 10⁻⁵ M  

According to Lambert-Beer law ;The rate of absorbance of a sample is directly proportional to concentration of the sample

The reaction that produces a red complex

Fe³⁺ + KScN ----> Fe ( SCN )₃  ( red complex )

First step:  Determine the Concentration of  Fe³⁺ in  reference sample

= 4.80x10⁻⁴ *  ( 5.0 / 50.0 ) = 4.80 * 10⁻⁵M  

reference sample was diluted from 5.0 mL to 50.0 mL

∴ Concentration of 4.80 * 10⁻⁵M  has an absorbance = 0.512

Given that Lake sample absorbance = 0.345

Next step : Determine the concentration of the lake sample

Concentration of lake sample :

= absorbance of lake sample * ( conc of reference sample / absorbance )

= 0.345 *  (  4.80* 10⁻⁵ / 0.512  )  = 3.23* 10⁻⁵M.

Final step : Determine the concentration of Fe³⁺ in Jordan  lake

=  3.23 * 10⁻⁵ *  ( 50.0mL / 20.0mL) = 8.09* 10⁻⁵ M  

Note :  Solution  was diluted from 20.0 mL to 50.0 mL

Hence we can conclude that The concentration of  Fe³⁺ in Jordan Lake is = 8.09* 10⁻⁵ M  .

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Answer:

the volume of the gas at conditions of STP = 151.04998 ml

Explanation:

Data given:

V1 = 180 ml

T1 = 35°C or 273.15 + 35 = 308.15 K

P1 = 95.9 KPa

V2  =?

We know that at STP

P2 = 1 atm or 101.3 KPa

T2 = 273.15 K

At STP the pressure is 1 atm and the temperature is 273.15 K

applying Gas Law:

[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]

putting the values in the equation of Gas Law:

[tex]V_2=\frac{P_1V_1T_2}{T_1P_2}[/tex]

V_2 =[tex]\frac{95.9\times180\times273.15}{308.15\times101.3}[/tex]

V2 = 151.04998

therefore, V2 = 151.04998 ml

Answer:

151 mL is the correct answer to the given question .

Explanation:

We know that

[tex]PV =n RT[/tex]

Where P =pressure ,V=volume and T=Temperature

Given

P=95.9 kPa.

V=[tex]180 * 10 ^{-3}[/tex]

R=25/3

T=273 + 35 =308k

Putting these value into the equation we get

[tex]95.9\ * 180\ *\ 10^{-3} \ =\ n * \frac{25}{3} * 308[/tex]

n=[tex]6.72 * 10^{-3}[/tex]

Now using the equation

[tex]n= \ \frac{V}{22.4}[/tex]

[tex]6.72 * 10^{-3} =\frac{V}{22.4}\\ V\ =\ 150.6mL[/tex]

This can be written as  151mL