2.4 Bromium has two naturally occurring isotopes: 79Br, with an atomic weight of 78.918 amu, and 81Br, with an atomic weight of 80.916 amu. If the average atomic weight for Br is 79.903 amu, calculate the fraction-of-occurrences of these two isotopes.

Answer:

0.712 moles of NO₂ are formed.

Explanation:

First, we need to write the balanced equation:

2 N₂O₅(g) ⇄ 4 NO₂(g) + O₂(g)

From the balanced equation, we can see the relationship between the moles of N₂O₅ and the moles of NO₂. Every 2 moles of N₂O₅ that react, 4 moles of NO₂ are formed. Let us apply this relationship to the information given by the problem (0.356 moles of N₂O₅):

[tex]0.356molN_{2}O_{5}.\frac{4molNO_{2}}{2molN_{2}O_{5}} =0.712molNO_{2}[/tex]

Sugar is the pure substance in the list. A chemical change occurs when methane gas is burned, as the chemical composition of methane is altered.

In the list provided, the pure substance is sugar. Pure substances are materials that are composed of only one type of particle, and sugar, which is made up of sucrose, meets this criterion. In contrast, substances like sea water, air, lemonade, and milk are mixtures, as they contain more than one kind of particle.

As for the second question, a chemical change happens when the composition of a substance is altered by a chemical reaction. In this scenario, the correct option is 'occurs when methane gas is burned'. Methane's combustion is a chemical reaction that produces water and carbon dioxide, which are chemically distinct from the original methane. Other options like shredding paper, vaporizing water, dissolving salt in water, or stirring powdered lemonade into water are all physical changes, as they don't alter the chemical composition of the substances involved.

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Sugar is considered a pure substance because it maintains the same composition and properties. A chemical change occurs when methane gas is burned, resulting in different substances.

From the given list, the pure substance is sugar. A pure substance has a constant composition. All specimens of a pure substance have exactly the same makeup and properties. An example of a pure substance is table sugar, or sucrose, which consists of 42.1% carbon, 6.5% hydrogen, and 51.4% oxygen by mass. It maintains the same physical properties, such as melting point, color, and sweetness, regardless of the source from which it is isolated.

Switching to the second question, the occurrence of a chemical change is evident when methane gas is burned. A chemical change always produces one or more types of matter that differ from the matter present before the change. An instance of this is the combustion or burning of methane which results in carbon dioxide and water. These yielded substances significantly differ from the original methane, hence signifying a chemical change.

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Answer:

11.7 mL

Explanation:

Density of a substance is given by the mass of the substance divided by the volume of the substance .

Hence , d = m / V

V = volume

m = mass ,  

d = density ,

From the question ,

The density of the metal = 10.5 g/cm³

The mass of the metal = 5.25 g

Hence , the volume can be calculated from the above formula , i.e. ,

d = m / V  

V = m / d

V = 5.25 g / 10.5 g/cm³

V = 0.5 cm³

Since , The unit 1 mL = 1 cm³

V = 0.5 mL

The vessel has 11.2 mL of water ,

The new volume becomes ,

11.2 mL +  0.5 mL = 11.7 mL

Answer:

a)Number average molecular weight is 50, 500 g/mol

b) Weight average molecular weight is 99, 019.8 g/mol

Explanation:

We have a polymer P made up of two monodisperse fractions.

A with molecular weight of MA = 1000 g/mol and B with MB =100000 g/mol.  

The batch contains an equal mole fraction of each component A and B.  

Let's suppose a total number (Nt) of mols 2 moles. Equal fraction means XA = 0.5 and XB =0.5

Nt = 2 mol

Na = 2*0.5 = 1 mol

Nb = 2*0.5 = 1 mol.

So, we have 1 mol of A, 1 mol of B and 2 moles in total.  

a) The number average molecular weight (NAM) is calculate using the mole numbers of each component. In this case, we will multiple each component molecular weight by the number of moles of each one. After that we will sum them and finally to divide by the total number of moles.

NAM = (Na*MA + Nb*MB)/(Nt)

NAM = (1 mol *1000 g/mol + 1*100000 g/mol ) /(2 mol)

NAM = 50500 g/mol

The number average molecular weight for the polymer P is 50,500 g/mol

b) Weight average molecular weight (WAM) is calculated using the mass quantities of each component. Weight mass of A (WA), weight mass of B (WB) are calculate using the moles of A, B and their molecular weights respectively. Total Weight (WT)

WA = Na*MA = 1 mol *1000 g/mol = 1000 g A

WB = Nb*MB = 1mol * 100000 g/mol = 100 000 gB

WT = WA + WB = 101 000 g

Now we will calculate average molecular using weights, we will multiple each component molecular weight by the mass of each one. After that we will sum them and finally to divide by the total mass.

WAM = (WA*MA + WB*MB)/(WT)

WAM = (1000 g *1000 g/mol + 100000 g*100000 g/mol )/(101 000 g)

WAM = 99 019.8 g/mol

The weight average molecular weight for polymer P is 99, 019.8 g/mol

Final answer:

The number average molecular weight (Mn) for the polymer is 50,500 g/mol, while the weight average molecular weight (Mw) is 198,019,802 g/mol, given the equal mole fraction of the two monomer fractions.

Explanation:

The  number average molecular weight (Mn) and the weight average molecular weight (Mw) of a polymer comprising two monodisperse fractions.

Firstly, to calculate the Mn, we consider the definition that Mn is the total weight of the polymer divided by the total number of moles. Since each fraction has an equal mole fraction, we take the simple average of the two given molecular weights:

Next, to compute the Mw, which is the sum of the products of the weight contribution of each fraction and its molecular weight squared, divided by the total weight:

To summarize, for a polymer with an equal mole fraction of two fractions with molecular weights of 1000 g/mol and 100,000 g/mol, the number average molecular weight is 50,500 g/mol and the weight average molecular weight is 198,019,802 g/mol.

Answer:

Chemical formula for the black iron oxide sample is FeO

Explanation:

Given:

Mass ratio of black iron oxide sample, Fe/O = 3.491

To determine:

The chemical formula

Calculation:

The mass ratio is Fe:O = 3.491 : 1

Mass of Fe = 3.491 g

Mass of O = 1.000 g

Atomic mass of Fe =55.85 g/mol

Atomic mass of O = 16.00 g/mol

[tex]Moles\ Fe = \frac{3.491g}{55.85g/mol} =0.625\\\\Moles\ O = \frac{1.000g}{16.00g/mol} =0.0625\\[/tex]

Therefore, the molar ratio of Fe:O = 1:1

Hence, chemical formula is FeO

Explanation:

FTIR spectroscopy is method which is used to determine structures of the molecules with characteristic absorption of the infrared radiation by the molecule.  

When the molecules is exposed to the infrared radiation, the sample molecules absorb the radiation of wavelengths (specific to molecule) which causes change of the dipole moment of the sample molecules. The vibrational energy levels of the sample molecules consequently transfer from the ground state to the excited state.  

Frequency of absorption peak is determined by vibrational energy gap.

Intensity of absorption peaks is related to change of dipole moment and possibility of transition of the energy levels.  

Thus, by analyzing infrared spectrum,abundant structure information of the molecule can be known.  

Most of the molecules/ compounds are infrared active but for homo-nuclear molecules which are diatomic like [tex]H_2[/tex], [tex]N_2[/tex], [tex]Cl_2[/tex], [tex]O_2[/tex] are inactive due to zero dipole change in vibration and the rotation of such molecules.

Final answer:

Molecular hydrogen does not produce an FTIR spectrum because as a homonuclear diatomic molecule, it does not have a change in dipole moment during vibration, which is a requirement for IR activity.

Explanation:

Molecular hydrogen does not produce a Fourier Transform Infrared (FTIR) spectrum because it is a homonuclear diatomic molecule, meaning it consists of two identical atoms. These molecules lack a permanent electric dipole moment, which is necessary for interaction with infrared light in FTIR spectroscopy. Infrared radiation can be absorbed by a molecule if the radiation causes a change in the dipole moment of the molecule, leading to vibrations within the molecule. Since molecular hydrogen's atoms are identical, they share electrons equally and there is no net dipole moment to be altered by the infrared radiation.

The fundamental requirement for a molecule to be IR active is a change in the molecular dipole moment as it vibrates. Homonuclear diatomic molecules like [tex]H_{2}[/tex] do not exhibit this change in dipole moment because the atoms involved are of the same electronegativity and thus share electrons equally, ensuing no dipole moment is generated during vibration. This is why molecular hydrogen doesn't show up on an FTIR spectrum.

Answer:

You have to weigh 0.079 g of Na₂S₂0₃ and dissolve it in water at a final volume of 250 ml.

Explanation:

A 0.00200 M Na₂S₂O₃ solution has 0.002 mol of Na₂S₂O₃ per liter of solution. As we know that 1 L = 1000 ml, and that the molecular weight of Na₂S₂O₃ IS 158 g/mol, we can calculate the mass of Na₂S₂O₃ to weigh as follows:

mass= [tex]\frac{0.002 mol Na2S2O3}{1000 ml solution}[/tex] x [tex]\frac{158 g}{1 mol Na2S2O3}[/tex] x 250 ml solution

mass= 0.079 g

To prepare the solution, we have to weigh in a beaker with 0.079 g of Na₂S₂O₃ by employing an analytical balance. Then, we have to dissolve the mass in a volume of aproximately 230 ml water. For this, we measure the 230 ml of water in a graduated cylinder, we add the volume to the beaker with the mass and we agitate until total disolution. Finally, we tranfer the total amount of the solution in the glass to a volumetric flask with a capacity of 250 ml. We add water until we reach the capacity, and then we homogenize the solution.

Answer: 12.5

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

[tex]Molarity=\frac{moles}{\text {Volume in L}}[/tex]

moles of [tex]NaOH=Molarity\times {\text {Volume in L}}=3.412\times 5.865\times 10^{-3}L=0.02moles[/tex]

moles of [tex]HCl=Molarity\times {\text {Volume in L}}=1.564\times 10^{-3}\times 0.5000L=0.782\times 10^{-3}moles[/tex]

[tex]NaOH+HCl\rightarrow NaCl+H_2O[/tex]

According to stoichiometry:  

1 mole of [tex]HCl[/tex]  require 1 mole of [tex]NaOH[/tex]

Thus [tex]0.782\times 10^{-3}moles[/tex]  will combine with  [tex]0.782\times 10^{-3}moles[/tex]  of [tex]NaOH[/tex]

Thus [tex](0.02-0.782\times 10^{-3})moles=0.019moles[/tex] of [tex]NaOH[/tex] will be left

Thus Molarity of [tex]OH^-=\frac{0.019}{0.56L}=0.03M[/tex]

[tex]pOH=-\log[OH^-][/tex]

Putting in the values:

[tex]pOH=-\log[0.03][/tex]

[tex]pOH=1.5[/tex]

[tex]pH+pOH=14[/tex]

[tex]pH=14-1.5=12.5[/tex]

Thus final pH will be 12.5.

Answer:

The 95% confidence level is

[tex]4.17 \pm 0.2744[/tex]

Explanation:

If we can apply the central limit theorem, we can approximate this distribution to a normal distribution.

The confidence level (for n=1) is defined as

[tex]X\pm \frac{z*\sigma}{\sqrt{n}}=X\pm z*\sigma[/tex]

For a 95% confidence interval, according to the normal distribution, z=1.96.

Then we have:

[tex]X\pm z*\sigma=4.17 \pm 1.96*0.14=4.17 \pm 0.2744[/tex]

Final answer:

To calculate the 95% confidence interval for a set of measurements with a mean of 3.095 g and a standard deviation of 0.0346 g, you first determine the standard error, then use it to find the margin of error, and finally compute the confidence interval, yielding an estimate that the true mean weight of a penny lies between 3.088 and 3.102 g.

Explanation:

To find the 95% confidence interval for a set of measurements, you utilize statistical principles that involve the mean, standard deviation, and sample size of the data. The basic formula to calculate the confidence interval is mean ± (critical value) * (standard deviation / √n), where √n is the square root of the sample size, and the critical value is determined based on the confidence level. For a 95% confidence level, the critical value (often represented as a z-score in the context of a normal distribution) is approximately 1.96.

Let's assume you're working with a sample size large enough for the central limit theorem to apply, simplifying the computation of the confidence interval to just involving the mean and standard deviation, due to a large sample size making the distribution of sample means approximately normal. Therefore, for the sample of 100 pennies with a mean of 3.095 g and a standard deviation of 0.0346 g, the 95% confidence interval can be calculated as follows:

This calculation reveals that we estimate with 95% confidence that the true mean weight of a penny lies between 3.088 and 3.102 g.

Answer:

1) The density of air at 40 degrees Celsius and 3 atm pressure is 3.4 g/L.

2) Molecular mass of linanyl acetate  is 196 g/mol.

Explanation:

1) Average molecular weight of an air ,M= 28.97 g/mol

[tex]PV=nRT[/tex]

or [tex] PM=dRT[/tex]

P = Pressure of the gas

T = Temperature of the gas

d = Density of the gas

M = molar mass of the gas

R = universal gas constant

P = 3 atm, T = 40°C = 313.15 K, M = 28.97 g/mol

[tex]d=\frac{PM}{RT}=\frac{3 atm \times 28.97 g/mol}{0.0821 atm L/ mol K\times 313.15 K}[/tex]

d = 3.4 g/mL

The density of air at 40 degrees Celsius and 3 atm pressure is 3.4 g/L.

2) Molecular formula of Linanyl acetate = [tex]C_{12}H_{20}O_2[/tex]

Atomic mass sof carbon  = 12.01 g/mol

Atomic mass of hydrogen = 1.01 g/mol

Atomic mass of oxygen  = 16.00 g/mol

Molecular mass of  Linanyl acetate :

[tex]12\times 12.01 g/mol+20\times 1.01 g/mol+2\times 16.00 g/mol =196.32 g/mol \approx 196 g/mol[/tex]

Answer:

1,816 L

Explanation:

Molar concentration or molarity is a way to express the concentration of a chemical in terms of moles of substances per liter of solution.

To obtain the liters of this solution you must convert moles/L to g/L with formula weight (FW), thus:

0,1107 mol of KCl / L × (74,6 g / mol) = 8,258 g of KCl / L.

It means that in one liter you have 8,258 g of KCl. Thus, 15,00 g of KCl are contained in:

15,00 g × (1 L / 8,258 g) = 1,816 L

I hope it helps!

Answer:

2.32 m

Explanation:

So, according to definition of mole fraction:

[tex]Mole\ fraction\ of\ benzene=\frac {n_{benzene}}{n_{benzene}+n_{toluene}}[/tex]

Mole fraction = 0.176

Applying values as:

[tex]0.176=\frac {n_{benzene}}{n_{benzene}+n_{toluene}}[/tex]

[tex]0.176\times ({n_{benzene}+n_{toluene}})={n_{benzene}}[/tex]

So,

[tex]0.176\times n_{toluene}}=0.824\times {n_{benzene}}[/tex]

[tex]{n_{benzene}}=\frac {0.176}{0.824}\times n_{toluene}}[/tex]

[tex]{n_{benzene}}=0.2136\times n_{toluene}}[/tex]

Also, Molar mass of toluene = 92.14 g/mol

Thus,

The formula for the calculation of moles is shown below:

[tex]moles = \frac{Mass\ taken}{Molar\ mass}[/tex]

[tex]Mass=92.14\times n_{toluene}}\ g[/tex]

Also, 1 g = 0.001 kg

So,

[tex]Mass\ of\ toluene=0.09214\times n_{toluene}}\ kg[/tex]

Molality is defined as the moles of the solute present in 1 kg of the solvent.

It is represented by 'm'.

Thus,  

[tex]Molality\ (m)=\frac {0.2136\times n_{toluene}}{0.09214\times n_{toluene}}[/tex]

Molality of benzene = 2.32 m

Final answer:

The molality of the solution of benzene dissolved in toluene is 0.00543 mol/kg.

Explanation:

The molality of a solution can be calculated using the mole fraction and the molar mass of benzene and toluene. The mole fraction of benzene can be calculated by dividing the moles of benzene by the total moles of benzene and toluene. The moles of benzene can be determined using the given volumes of benzene and toluene and their respective densities. The molar mass of benzene is 78.11 g/mol. By substituting the values into the formula, we can calculate the molality of the solution to be 0.176 * 78.11 g/mol / (1000 g + 0.867 g/mL * 100 mL + 0.874 g/mL * 300 mL) = 0.00543 mol/kg.

Answer:

A) blue crystal

Explanation:

Qualitative measurements measure the quality of something as opposed to quantity. The other options are quantitative as they contain numbers.

Answer:

-1.06

Explanation:

0.345 has three significant figures since the zero does not represent a significant figure.

So, usign the calculator, we find ln (0.345) = -1.06421086195

Now, the problem says that you need to report your answer to three significant figures.

So, you should take the first three numbers of the answer:

ln (0.345) = -1.06

a.) Asp and Lys

Asp will elute first from the column because it has less positively charged functional groups than Lys.

b.) Arg and Met

Met will elute first from the column because it has less positively charged functional groups than Lys.

c.) Glu and Val

Glu will elute first from the column because it has more negativity functional groups than Lys and will be not be much retained by the -SO₃⁻ groups from the ion-exchange coloumn.

d.) Gly and Val

 Gly will elute first from the column because Lys have a longer alkyl chain which will be attracted by the strongly hydrophobic backbone for the resin.

e.) Ser and Ala

Ser will be eluted first from the column because Ala alkyl chain will be more attracted by the strongly hydrophobic backbone for the resin. Ser have an -OH group which will decrease the hydrophobicity of the alkyl chain and will not be so much retained on the column.

Answer : The overall mixture flow rate is 11905.71 lb.mass/hour

Explanation :

As we are given that 16.0 weight percent methanol. That means, 16.0 g of methanol present in 100 g of mixture (methanol-methyl acetate).

Mass of methanol = 16.0 g

Mass of mixture = 100 g

Mass of methyl acetate = 100 - 16.0 = 84.0 g

Now converting flow rate of methyl acetate from lb.mols/hour to lb.mass/hour.

[tex]\text{lb.mols/hour}=(\text{lb.mols/hour})\times \text{Molar mass}=\text{lb.mass/hour}[/tex]

Molar mass of methyl acetate = 74.08 g/mols

So, [tex]135.0\text{ lb.mols/hour}=(135.0\text{ lb.mols/hour})\times 74.08g/mols=10000.8\text{ lb.mass/hour}[/tex]

Now we have to calculate the overall mixture flow rate.

As, 84 g of methyl acetate flow rate = 10000.8 lb.mass/hour

So, 100 g of mixture flow rate = [tex]\frac{100}{84}\times 10000.8\text{ lb.mass/hour}=11905.71\text{ lb.mass/hour}[/tex]

Therefore, the overall mixture flow rate is 11905.71 lb.mass/hour

Final answer:

to find the overall mixture flowrate in lb,mass/hour, we add the flowrates of methyl acetate and methanol: F = FMA + FM = 135.0 + 21.6 = 156.6 lbmols/hour.

Explanation:

To find the overall mixture flowrate in lb,mass/hour, we need to determine the flowrate of methyl acetate and its weight percent in the mixture.

Given the flowrate of methyl acetate is 135.0 lbmols/hour and the weight percent of methanol is 16.0%, we can find the flowrate of methanol in the mixture. Let's denote the overall mixture flowrate as F, the flowrate of methyl acetate as FMA, and the flowrate of methanol as FM.

Since the weight percent of methanol is 16.0%, the weight percent of methyl acetate is 100% - 16.0% = 84.0%. This means that the weight ratio of methyl acetate to methanol in the mixture is 84.0% / 16.0% = 5.25.

Therefore, we can write the equation FMA / FM = 5.25. Solving for FM, we get FM = F / (1 + 5.25) = F / 6.25. Substituting the given flowrate of methyl acetate (135.0 lbmols/hour) into the equation, we get FM = 135.0 / 6.25 = 21.6 lbmols/hour.

Finally, to find the overall mixture flowrate in lb,mass/hour, we add the flowrates of methyl acetate and methanol: F = FMA + FM = 135.0 + 21.6 = 156.6 lbmols/hour.

Answer:

1.930 * 10⁻⁹ mg of Mn⁺² are left unprecipitated.

Explanation:

The reaction that takes place is:

Mn⁺² + S⁻² ⇄ MnS(s)  

ksp = [Mn⁺²] [S⁻²]

If the pksp of MnS is 13.500, then the ksp is:

[tex]ksp=10^{-13.500}=3.1623*10^{-14}[/tex]

From the problem we know that [S⁻²] = 0.0900 M

We use the ksp to calculate [Mn⁺²]:

3.1623*10⁻¹⁴= [Mn⁺²] * 0.0900 M

[Mn⁺²] = 3.514 * 10⁻¹³ M.

Now we can calculate the mass of Mn⁺², using the volume, concentration and atomic weight. Thus the mass of Mn⁺² left unprecipitated is:

3.514 * 10⁻¹³ M * 0.1 L * 54.94 g/mol = 1.930 * 10⁻¹² g = 1.930 * 10⁻⁹ mg.

Answer:

2.6 sec

Explanation:

The distance between the Earth and the moon = 240,000 miles

Also,

1 mile = 1609.34 m

So,

Distance between the Earth and the moon = 240,000 ×  1609.34 m = 386241600 m

Speed of the light = 3 × 10⁸ m/s

Distance = Speed × Time.

So,

Time = Distance / Speed = 386241600 m / 3 × 10⁸ m/s = 1.3 sec

For back journey = 1.3 sec

So, total time = 2.6 sec

Answer:

concentration of CrO4²⁻ ions in the final solution = 6.53 × 10⁻⁵ mol /L

Explanation:

First we calculate the number of moles of AgNO₃:

number of moles = molar concentration × volume

number of moles = 0.5 × 39.20 = 19.6 mmoles = 0,0196 moles AgNO₃

Then we calculate the number of moles of K₂CrO₄:

number of moles = mass / molar weight

number of moles = 5.832 / 194 = 0.03 moles K₂CrO₄

The chemical reaction will look like this:

2 AgNO₃ + K₂CrO₄ → Ag₂CrO₄ + 2 KNO₃

Now we devise the following reasoning:

if          2 moles of AgNO₃ are reacting with 1 mole of K₂CrO₄

then    0,0196  moles of AgNO₃ are reacting with X moles of K₂CrO₄

X = (0.0196 × 1) / 2 = 0.0098 moles of K₂CrO₄

now the the we calculate the amount of unreacted K₂CrO₄:

unreacted K₂CrO₄ = 0.03 - 0.0098 = 0.0202 moles

now the molar concentration of CrO4²⁻ ions:

molar concentration = number of moles / solution volume (L)

molar concentration = 0.0202 / (39.20 + 270) = 6.53 × 10⁻⁵ mol /L

Answer:

density = 7.55 g/cm^3

Explanation:

we need to get the volume first to get the density , and the volume formula is:

the volume = area * thickness

where :

area = 2 cm * 2 cm = 4 cm^2

and thickness = 100 cm

by substitution:

the volume = 4 * 100 = 400 cm^3

where

density = mass / volume

we have to convert mass from kg to g = 3020 g

by substitution:

density = 3020 g / 400 cm^3

           = 7.55 g/cm^3

Answer :

[tex]Cl_2[/tex] is reduced species.

[tex]KI[/tex] is oxidized species.

[tex]Cl_2[/tex] is oxidizing agent.

[tex]KI[/tex] is reducing agent.

Explanation :

Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.

Reducing agent : It is defined as the agent which helps the other substance to reduce and itself gets oxidized. Thus, it will undergo oxidation reaction.

Oxidizing agent : It is defined as the agent which helps the other substance to oxidize and itself gets reduced. Thus, it will undergo reduction reaction.

The balanced redox reaction is :

[tex]Cl_2(aq)+2KI(aq)\rightarrow 2KCl(aq)+I_2(aq)[/tex]

The half oxidation-reduction reactions are:

Oxidation reaction : [tex]2I^-\rightarrow I_2+2e^-[/tex]

Reduction reaction : [tex]Cl_2^++2e^-\rightarrow 2Cl^-[/tex]

From this we conclude that the [tex]'KI'[/tex] is the reducing agent that loses an electron to another chemical species in a redox chemical reaction and itself gets oxidized and [tex]'Cl_2'[/tex] is the oxidizing agent that gain an electron to another chemical species in a redox chemical reaction and itself gets reduced.

Thus, [tex]Cl_2[/tex] is reduced species.

[tex]KI[/tex] is oxidized species.

[tex]Cl_2[/tex] is oxidizing agent.

[tex]KI[/tex] is reducing agent.

Iodine from potassium iodide (KI) is oxidized, and chlorine from chlorine gas (Cl2) is reduced; Cl2 is the oxidizing agent and KI is the reducing agent in the reaction.

In the reaction Cl2(aq) + 2 KI(aq) → 2 KCl(aq) + I2(aq), the oxidized species is iodine (I) from potassium iodide (KI), and the reduced species is chlorine (Cl) from chlorine gas (Cl2). During the reaction, I- loses electrons and is therefore oxidized to I2; its oxidation number changes from -1 to 0. Conversely, each Cl atom in Cl2 gains one electron to become Cl-, going from an oxidation state of 0 to -1. Thus, the oxidizing agent is Cl2 because it accepts electrons (is reduced), and the reducing agent is KI because it donates electrons (is oxidized).

Answer:

C H2SO4 = 9.79 M

Explanation:

∴ %w/w H2SO4 = 960% = g H2SO4 / g sln * 100

⇒ 9.6 = g H2SO4 / g sln

calculation base: 1000 g sln

⇒ g H2SO4 = 9600g

⇒ mol H2SO4 = 9600 g H2SO4 * ( mol H2SO4/ 980g H2SO4 ) = 9.796  mol H2SO4

⇒ V sln = 1000g sln / 1000g/L = 1 L sln

∴ ρ H20 ≅ 1000 Kg/m³ = 1000 g/L

⇒ C H2SO4 = 9.796 mol H2SO4 / 1 L sln

⇒ C H2SO4 = 9.796 M

Answer:

All of them can be necessary.

Explanation:

In typical DNA cloning, the gene of interest is inserted into a plasmid, this is achieved by using enzymes that "cut and paste" DNA producing a recombinant DNA, considering this we will first need a DNA fragment to be cloned. To "cut and paste" these fragments of DNA we will need restriction enzymes (to cut) and DNA ligase (to paste), this enzyme will recognize the specific target sequence and I'll cut it, another restriction enzyme will also cut the plasmid, then DNA ligase will link the plasmid and target gene together. Now we need to introduce the plasmid into bacteria, to extract it we use glucose as a buffer to maintain the pH-controlled for the plasmid to be stable, so that linear dsDNA (sheared chromosomal DNA) is denatured but closed-circular DNA (plasmid) is not. Once we have our plasmid isolated we can put it into our bacteria (this is called transformation), this is achieved by giving the bacteria a shock that encourages them to take foreign DNA, calcium chloride can improve the results by binding plasmids to lipopolysaccharides in the bacteria. After this shock, some bacteria will accept the plasmid but a portion won't, this is why plasmids typically contain antibiotic resistance genes to allow the bacteria that contain the plasmids to survive after the application of such antibiotic, this means ampicillin is also necessary to isolate our bacteria with recombinant DNA. Finally, you can use these bacteria as "factories" to produce proteins and then obtain them by splitting the bacteria, to achieve this splitting we can use proteases, for example, chymotrypsin. NOw you'll need to purify the proteins you extract one method to do it is using the starch binding domain (SBD) that can be found in some amylolytic enzymes, we can add a recombinant proteins for transferring the starch binding capacity to the target proteins, we will observe both proteins fused to the SBDtag, only the target protein will remain over the starch granules after the wash process.

I hope you find this information useful and interesting! good luck!

Answer : The percent yield of [tex]P_2O_5[/tex] is, 30.39 %

Solution : Given,

Mass of P = 2.80 g

Molar mass of P = 31 g/mole

Molar mass of [tex]P_2O_5[/tex] = 284 g/mole

First we have to calculate the moles of P.

[tex]\text{ Moles of }P=\frac{\text{ Mass of }P}{\text{ Molar mass of }P}=\frac{2.80g}{31g/mole}=0.0903moles[/tex]

Now we have to calculate the moles of [tex]NH_3[/tex]

The balanced chemical reaction is,

[tex]4P+5O_2\rightarrow 2P_2O_5[/tex]

From the reaction, we conclude that

As, 4 mole of [tex]P[/tex] react to give 2 mole of [tex]P_2O_5[/tex]

So, 0.0903 moles of [tex]P[/tex] react to give [tex]\frac{0.0903}{4}\times 2=0.04515[/tex] moles of [tex]P_2O_5[/tex]

Now we have to calculate the mass of [tex]P_2O_5[/tex]

[tex]\text{ Mass of }P_2O_5=\text{ Moles of }P_2O_5\times \text{ Molar mass of }P_2O_5[/tex]

[tex]\text{ Mass of }P_2O_5=(0.04515moles)\times (284g/mole)=12.8g[/tex]

Theoretical yield of [tex]P_2O_5[/tex] = 12.8 g

Experimental yield of [tex]P_2O_5[/tex] = 3.89 g

Now we have to calculate the percent yield of [tex]P_2O_5[/tex]

[tex]\% \text{ yield of }P_2O_5=\frac{\text{ Experimental yield of }P_2O_5}{\text{ Theoretical yield of }P_2O_5}\times 100[/tex]

[tex]\% \text{ yield of }P_2O_5=\frac{3.89g}{12.8g}\times 100=30.39\%[/tex]

Therefore, the percent yield of [tex]P_2O_5[/tex] is, 30.39 %

To determine the percent yield of a reaction, compare the actual yield to the theoretical yield. The theoretical yield can be calculated using stoichiometry and the balanced equation. In this case, the percent yield is 60.7%.

To determine the percent yield of a reaction, you need to compare the actual yield to the theoretical yield. The theoretical yield is the maximum amount of product that can be formed according to the stoichiometry of the balanced equation. In this case, the balanced equation is 4 P + 5 O2 → 2 P2O5. The molar mass of P2O5 is 141.944 g/mol, so the theoretical yield can be calculated as:

Therefore, the theoretical yield is 6.41 g P2O5. To calculate the percent yield, divide the actual yield by the theoretical yield and multiply by 100:

Percent Yield = (Actual Yield ÷ Theoretical Yield) × 100
Percent Yield = (3.89 g ÷ 6.41 g) × 100 = 60.7%

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Answer:

Volumetric flow rate: Q = 1000 L/s

Explanation:

Volumetric flow rate, also called the rate of fluid flow, is described as volume of fluid that passes a particular point per unit time. The SI unit of volumetric flow rate is m³/s.  

Whereas, mass flow rate is defined as the mass of substance that passes through a point per unit of time. SI unit is kg/s.

Given- mass flow rate: ṁ = 1 kg/s and density: ρ = 1 kg/m³

Therefore, volumetric flow rate can be calculated by

[tex]Q = \frac{\dot{m}}{\rho } = \frac{1 kg/s}{1 kg/m^{3}} = 1 m^{3}/s[/tex]

Since, 1 m³/s = 1000 L/s

Therefore, volumetric flow rate: Q = 1 m³/s = 1000 L/s

Answer: The given isotope of tin has 50 protons and 69 neutrons.

Explanation:

Atomic number is defined as the number of protons or number of electrons that are present in neutral atom. It is represented as Z.

Atomic number = Number of protons = Number of electrons

Mass number is defined as the sum of number of protons and number of neutrons. It is represented as A.

Mass number = Number of protons + Number of neutrons

We are given:

An isotope having representation [tex]_{50}^{119}\textrm{Sn}[/tex]

Mass number of Sn = 19

Atomic number = 50

Number of neutrons = Mass number - Atomic number = 119 - 50 = 69

Hence, the given isotope of tin has 50 protons and 69 neutrons.

Answer:The student should be wearing a lab coat or maybe an apron to prevent chemicals from spilling or exploding onto their clothes, I do recommend a lab coat better though because it can protect your skin better. Next, make sure while messing with chemicals you are always wearing goggles, if you are not wearing them there is a chance that after touching chemicals you could touch your eyes. And that brings me to washing your hands straight away after messing with chemicals. You could also wear gloves and just take them off when you're done but if you don't have clean hands afterward you could always put the chemicals all over your skin. But in case you do touch your eyes there is always an emergency eyewash station somewhere in the lab room. And if you are to get Chemicals on your skin, in your hair, on your clothes, or to be on fire, there shall be a shower somewhere to get rid of that. But if you read the instructions or listen closely to the teacher you shall have no problem.

Explanation:

I kinda got off topic

When a student is warming a chemical in a container using a special burner, it is very important to focus on safety by using the right safety tools.

First, the student needs to wear the right safety clothes like a lab coat, gloves, and goggles to protect themselves from getting splashed or hurt by chemicals. A lab coat stops chemicals from touching the skin, gloves keep the hands safe, and safety goggles protect the eyes from chemicals

and hot things.

Furthermore, using a fume hood is necessary to make sure there is enough fresh air circulating and to remove any dangerous fumes or gases that might be released while heating things up.

Read more about safety equipment here:

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Answer:

[tex]3.446\times 10^{-2}[/tex]

Explanation:

Scientific notation is the way of writing numbers which are either large or small. The number is written in the scientific notation when the number is between 1 and 10 and then multiplied by the power of 10.

The given number:

0.03445750 can be written as [tex]3.445750\times 10^{-2}[/tex]

Answer upto 4 significant digits = [tex]3.446\times 10^{-2}[/tex]

Answer:

a) ppm

b) ppm

c) ppb

d) ppt

e) ppb

Explanation:

a) You know that 1000 g are 1 kg, and 1000 kg are 1 ton, so (1000)*(1000) g are 1 ton, so 1,000,000 grams are one ton.

b) 1000 mg are 1 g, and 1000 g are 1 liter, so 1,000,000 grams are one liter.

c) You know that 1000 ug are 1 mg, so with the b), we just need to multiply the answer by 1000, so 1,000,000,000 ug are 1 liter.

d) The same as c, 1000 ng are 1 mg. So we are talkinf of ppt.

e) 1000 mg are 1 g. And 1000 g are 1 kg, then 1000 kg are one ton. So 1,000,000,000 mg are one ton.

Answer: 72.41% and 26.90% respectively.

Explanation:

At 60°C, you can dissolve 46.4g of acetanilide in 100mL of ethanol. If you lower the temperature, at 0°C, you can dissolve just 12.8g, which means (46.4g-12.8g)=33.6g of acetanilide must have precipitated from the solution.

We can calculate recovery as:

[tex]\%R=\frac{crystalized\ mass}{initial\ mass}*100 =\frac{33.6\ g}{46.4\ g}*100=72.41\%[/tex]

So the answer to the first question is 72.41%.

For the second part just use the same formula, the mass of the precipitate is the final mass minus the initial mass, (171mg-125mg)=46mg.

[tex]\%R=\frac{crystalized\ mass}{initial\ mass}*100 =\frac{46\ mg}{171\ mg}*100=26.90\%[/tex]

So the answer to the second question is 26.90%.