A university class has 12 students enrolled, 2 of whom are graduate students.
What is the probability that a randomly chosen student will be a graduate
student?
Write your answer as a fraction or whole number.
P(graduate student)
=

A 40.0 ml sample of 0.25 m KOH is added to 60.0 ml of 0.15 m Ba(OH)₂.  the molar concentration of OH⁻ ion in the resulting solution is 0.28 M.

Given that :

volume of KOH = 40 mL = 0.04 L

Molarity of KOH = 0.25 M

volume of  Ba(OH)₂ = 60 mL = 0.06 L

molarity of  Ba(OH)₂ = 0.15 M

moles of OH⁻ in KOH = 0.04 × 0.25 = 0.01

moles of OH⁻ in Ba(OH)₂ = 2 (0.06 × 0.15) = 0.018

total no. of moles = 0.01 + 0.018 = 0.028 mol

total volume = 0.04 + 0.06 = 0.1 L

molarity of OH⁻ ion = moles / volume

                                 = 0.028 / 0.1

                                 = 0.28 M

Thus, A 40.0 ml sample of 0.25 m KOH is added to 60.0 ml of 0.15 m Ba(OH)₂.  the molar concentration of OH⁻ ion in the resulting solution is 0.28 M.

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melting of gold, burning of magnesium, and water evaporation.

One instance of a physical change is melting. A physical change is when a sample of matter experiences a change in some of its qualities but not in its identity. Water turns into water vapor when it is heated.

Physical changes, such as melting, evaporation, and condensation, are different from those that result in the synthesis of new materials through chemical reactions.

Magnesium reacts with water to produce hydrogen gas, which, when exposed to the intense heat and oxygen present in air, ignites explosively. When it reacts, the heat generated causes the water molecule to shrink and transform into hydrogen gas.

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If you compare 1 M Nacl solution, 1M glucose solution and 1M sucrose solution,1M Nacl solution is more hypertonic due to the dissociation of ions in the solution.

Of the two solutions the solution with higher osmotic pressure is called hypertonic. The extra pressure developed on the solution side due to the diffusion of solvent from its high amount through a semipermeable membrane is called the osmotic pressure.

    Osmotic pressure= icRT

     Where, i= van't hoff factor

                  c= concentration

                   R=Gas constant

                   t= temperature

The extent of dissociation or association of a solute in solution is expressed in terms of the van't hoff factor.

In 1M Nacl, as Nacl dissociates into ions in the solution its van't hoff factor becomes 2. In  1 M glucose it doesn't dissociate into ions. So van't hoff factor remains 1. And In 1 M sucrose,as  it does not dissociate into ions van't hoff factor  remains 1. So here Nacl has more osmotic pressure.

So, Nacl is hypertonic because of its dissociation into ions in the solution.

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The percent difference between the pressure calculated using the van der waals' equation and the ideal pressure is 5.89 %.

This can be calculated using van der waals' equation, followed by calculating pressure difference by: [P(ideal)-P(Van der waal's equation)/P(ideal)]*100

P(ideal) is given: 16.45

P(van der waals'): [tex](P+n2aV2)(V−nb)=nRT[/tex]

T= 270.9K  

V=1.301 L

a for oxygen = 1.36 (L2 atm mol-2)

b for oxygen =  0.0319 (L mol-1)

n= 0.9686 mol

Using equation P(van der waals's) = 15.48 bar

and difference is 5.81%

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Methane is the common name for methane. In the organic molecule, it is the simplest hydrocarbon and a hydride of carbon. Tetrahedral in shape and with an exact bond angle of 109.50 in Lewis structure.

The methane molecule has the Lewis structure, Dots are used to indicate the positions of electrons surrounding the atoms in a molecule, while lines or pairs of dots are used to represent covalent connections between atoms in a Lewis structure. The goal of creating a Lewis dot structure is to locate the molecules' lone electron pairs in order to establish how chemical bonds are formed. Natural gas's primary component and the simplest alkane is methane, a chemical molecule with the molecular formula methane (one carbon atom bound to four hydrogen atoms).

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In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge.  Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron. The correct option is option A.

Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.

Quarks are present in protons and neutrons but not in electrons. Quarks are sub-atomic particles that have mass, but not an integer of charge.

Therefore, the correct option is option A.

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Answer:

1. 0.48 M  2. 0.00814 M  3. 0.1276 M

Explanation:

1. Convert the 40 g to moles using the molar mass of C6H12O6:

40 g C6H12O6/180.16 g C6H12O6 = 0.222 mol

Then divide the number of moles by liters to find molarity:

0.222 mol/1.5 L = 1.48 M

2.  Convert the 1.55 g to moles using the molar mass of KBr:

1.55 g KBr/119 g KBr = 0.013025 mol

Then divide the number of moles by liters to find molarity:

0.013025 mol/1.60 L = 0.00814 M

3. Convert the 9.5 g to moles using the molar mass of NaOCl:

9.5 g NaOCl/180.16 g NaOCl = 0.1276 mol

Then you divide the number of moles by liters to find molarity:

0.1276 mol/1 L = 0.1276 M

The pressure inside the vessel at temperature of 35 degree Celsius is 0.51atm.

According to the ideal gas equation,

PV = nRT

Where,

P is the pressure of the vessel,

V is the volume of the vessel which is 2.9 L in this case,

n is the number of moles of gas,

R is the gas constant,

T is the temperature of the gas.

n = 2.6/44

R = 0.082 m³-atm/kmol-K

Temperature = (35+273) K.

Temperature = 308° K

Putting the values,

P = 2.6/44 x 0.082 x 308/2.9

P = 0.51 atm.

The pressure of the vessel is 0.51 atm.

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Answer:

the missing component is the option (a) electron

Explanation:

this is a nuclear decay of Th which resulted in the emission of alpha particles, equivalent to high speed electrons.

Sleet ,freezing of raindrops, snowflakes Precipitation

are 4 non examples of condensation .

What is condensation ?

Condensation, the separation of a liquid or solid from a vapor, generally occurs on surfaces that are cooler than the adjacent gas. A substance condenses when the pressure exerted by that vapor exceeds the vapor pressure of the substance's liquid or solid phase at the temperature of the surface on which condensation is occurring. As the steam condenses, heat is released. If this heat is not removed, the surface temperature will rise until it matches the surrounding steam.

If the air does not contain small particles, so-called aerosols, condensation will only occur if the air is extremely supersaturated with water vapor.

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Because of Avogardo Hypothesis, volumes can be used in gas phase reaction stoichiometry at constant temperature and pressure.

Avogadro's Law (also known as Avogadro's Hypothesis or Avogadro's Principle) is an experimental gas law that relates the volume of gas to the amount of gaseous matter present.

Avogadro's law states that "equal volumes of all gases at the same temperature and pressure have the same number of molecules". At constant temperature and pressure, (mol) of a gas is directly proportional.

For example, if two ideal gases, hydrogen and nitrogen, are mixed in equal amounts, they contain the same amount of molecules. This only happens if they are kept at the same pressure and temperature. This shows the ideal behavior of gases.

Let's look at this law mathematically: the overall law can be written as

V is directly proportional to n

or V = nK , K (a constant)

Amount of gas; “n” is the gaseous substance measured in moles. "k" is a constant defined for a specific pressure and temperature.

Comparing the same gas under different conditions, the law is : V₁/ n₁=V₂/ n₂

The equation shows that the number of moles of gas increases in proportion to the increase in gas volume. Therefore, the total number of atoms or molecules present in a given volume of gas is completely independent of the molar mass or size of the gas.

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The impedance of an AC circuit with 10 ohm resistor, 12 ohm inductive reactance and 7 ohm capacitive reactance is 11.2 ohm.

What is impedance?

Impedance is the resistance of a circuit to AC which is caused by the combining effects of ohmic resistance and reactance. It is represented by the symbol Z and its unit is ohm. It is a measure of opposition to electric flow.

The impedance of an AC circuit can be calculated by,

Z = [(R^2) + (XL - XC)^2]^1/2

where R = resistance, XL = inductive reactance, XC = capacitive reactance

Z = [(10^2) + (12 - 7)^2]^1/2 = (100 + 25)^1/2 = 11.2 ohm.

Therefore, the impedance of an AC circuit with 10 Ohm resistor, 12 ohm inductive reactance and 7 ohm capacitive reactance is 11.2 ohm.

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The mass of silver chloride produced is 24.79g.

Given,

volume = 1.11 L

Molarity = 0.156 M

First, convert molarity to moles by multiplying by the volume:

0.156 M AgNO3 = (0.156 moles AgNO3)/1 L x 1.11 L = 0.173 moles AgNO3

We are only interested in AgCl, not AgNO3. We convert moles of silver nitrate to moles of silver chloride using the balanced equation. This is a 1:1 conversion:

0.173 moles AgNO3 x (1 mole AgCl)/(1 mole AgNO3) = 0.173 moles AgCl

To get mass from moles, we multiply by the molar mass:

0.173 moles AgCl x (143.32 g/mol) =  24.79 g AgCl

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0.021 moles of KCN are required, to prepare a buffer with a pH of 9.230

A buffer, an aqueous solution consists of a mixture of a weak acid and its conjugate base or vice versa. Addition of a small amount of strong acid or strong base hardly changes the pH.

Given,

Volume = 125 mL

Concentration of HCN = 0.420 M

pH = 9.230

Moles of HCN = Volume × Concentration

= 0.125 × 0.420

= 0.0525 moles

HCN + KOH ⇄ KCN + H₂O

0.0525 + X   ⇄    0                     [initially]

(0.0525 - X) + 0  ⇄ X                  [At equilibrium]

pH = pKₐ + log [salt]/[acid]

9.230 = 9.31 + log [salt]/[acid]

-0.08 = log [salt]/[acid]

0.83 = [salt]/[acid]

X / (0.0525 - X) = 0.83

X = 0.021 moles of KCN

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The plants and animal cells are different because:

-Vacuoles are much larger in plant cells than in animal cells because they hold more water to stay upright

-Plant cells have cell walls to provide a stronger external structure and animal cells do not.

-Special organelles called chloroplasts are found in plant cells and not in animal cells to allow them to produce their own food.

In the field of biology, cells can be described as the building blocks from which all life forms on Earth are built.

Plant cells have chloroplast through which light energy can be trapped. This light energy is used by plants to make their own food. The animal cells lack chloroplast because they do not make their own food.

Plants cells have the cell wall as the outermost covering whereas animal cells do not have a cell wall. The outermost covering of the animal cells is the cell membrane only.

A plant cell has a single, large vacuole in the middle of the cell that is used for maintaining turgidity and storing water. Animal cells do not have smaller and numerous vacuoles.

Although a part of your question is missing, you might be referring to this question:

Plant and animal cells are very similar, but they also contain certain differences. how are plant and animal cells different? choose three correct answers.

Vacuoles are much larger in plant cells than in animal cells because they hold more water to stay upright

Animal cells contain a nucleus and plant cells do not

Plant cells have cell walls to provide a stronger external structure and animal cells do not.

Plant and animal cells are both completely the same and they have no differences.

Special organelles called chloroplasts are found in plant cells and not in animal cells to allow them to produce their own food.

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The ions are present in cations and anions.

The cathode Positively charged cations.

The anode is negative ions.

The oxidation occurs is Zn(s) = Zn2+ (aq) + (2e-).

A redox reaction combines two half-reactions into one complete formula. Electrons lost in the oxidation half-reaction are gained in the reduction half-reaction. Thus, a redox reaction is a chemical reaction in which electrons are transferred between the two species.

A substance that is reduced in a chemical reaction is called an oxidizing agent and a substance that is oxidized is called a reducing agent. Example of the redox reaction of zinc and copper. A reaction is complete when it reaches equilibrium, that is when the concentrations of reactants and products stop changing. If the equilibrium constant is very large.

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Answer:

The chemical compound responsible for ocean acidification in the open oceans of the world is carbon(II) oxide

The chemical compound responsible for ocean acidification in the open oceans of the world is carbon(II) oxide.

Ocean acidification is the global decrease in seawater pH caused by the oceans' extensive uptake of atmospheric carbon dioxide (CO2) in the atmosphere. Ocean acidification is primarily caused by the Earth's atmosphere being overburdened with massive amounts of CO2, which is created by automobiles, industrial processes, and agricultural activities.

A third to a half of the CO2 produced into the atmosphere by human activity since the start of the Industrial Revolution, or around 1750, is being absorbed by the oceans. Scientists believe that at that time, seawater's average pH decreased between 8.19 to 8.05, representing a 30% increase in acidity. The chemical compound responsible for ocean acidification in the open oceans of the world is carbon(II) oxide.

Therefore, the chemical compound responsible for ocean acidification in the open oceans of the world is carbon(II) oxide.

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The homozygous dominant genotype is 0%, the heterozygous genotype is 50%, and the homozygous recessive genotype is 50%.

This problem does not display the Punnett box. If the genotype of the heterozygous parent has spots (Ff) and the other parent is homozygous without spots, the cross between the two parents is:

Parental: Ff >< ff

Gametes: F . f >< f

Filial: Ff (heterozygous having freckles) and ff (recessive homozygous over not having freckles)

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Answer: 0%, 50%, 50%

Explanation:

Assume at the end of step b in “The Copper Cycle” experiment, we had only solid product b and water. Considering the reactions after that, the ions present in the water before the rinsing and decanting are: copper (II) ions and hydroxide ions.

The copper cycle experiment aims to perform a series of reactions that regenerate elemental copper at the end of the copper cycle. In this cycle, the reaction series includes single replacement, double replacement, synthesis, and decomposition reactions.

In step b, the ions that exist in the water are copper (II) and hydroxide ions which are stated as: [Cu(H2O)6]2+(aq) + 2OH- --> Cu(OH)2(s) + 6H2O(l).

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The volume of a 2.0 m solution of NaOH needed to prepare 494.4 ml of a 0.15 m solution of NaOH is 37.08 ml.

Dilution is defined as the process in which the concentration of a sample is decreased by adding more solvent. The dilution formula is given below.

C₁V₁ = C₂V₂

where C₁ = initial concentration of sample = 2.0 m

V₁ = initial volume of sample

C₂ = final concentration after dilution = 0.15 m

V₂ = total final volume after dilution = 494.4 ml

Plug in the values to the formula and solve for the volume of the solution needed.

V₁ = C₂V₂/C₁

V₁ = (0.15 m)(494.4 ml)/(2.0 m)

V₁ = 37.08 ml

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Answer:

All forms of hydroxides

Explanation:

The metals in Group IA (Li, Na, K, Rb, Cs, and Fr) are called alkali metals because they all form hydroxides (such as NaOH) that were once known as alkalies. The electron configurations of the alkali metals are characterized by a single valence electron.

Iron bromide will form principate during the reaction.

When cations as well as anions in an aqueous solution combine to generate a precipitate, an insoluble solid, precipitation processes take place.

When target ion concentrations were identical, the ion that forms the poorest soluble compound would precipitate initially (at the lowest counter ion concentration), followed by the other ions as when the solubilities of respective compounds are attained.

When fe2(co3)3 reacts with mgbr2 then it will form iron bromide and magnesium carbonate.

Its chemical reaction can be written as:

[tex]Fe_{2}CO_{3} +MgBr_{2}[/tex] →[tex]FeBr_{3} +MgCO_{3}[/tex]

Here, magnesium carbonate will form ppt because it it will be a insoluble.

That's why it can be said that it will form ppt during the reaction.

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The diode is forward-biased. The acceptor concentration on the p-side is [tex]N_{A}[/tex] = 10¹⁶ cm⁻³. The donor concentration on the n-side is [tex]N_{D}[/tex] = 10¹⁴ cm⁻³.  The intrinsic carrier concentration is [tex]n_{i}[/tex] = 3.16×10¹¹ cm⁻³. Yes, the low-level injection condition applies. The bias (in volts) applied to the diode is [tex]V_{A}[/tex] = 0.18V.

The diode is forward-biased because of the excess electrons on the P-side and the excess holes on the N-side. In the intrinsic carrier concentration on the P-side n₀p₀ = 10¹⁶ × 10⁷ = 10²³ = [tex]n_{i}[/tex] = √10²³ = 3.16×10¹¹ cm⁻³, while on the N-side n₀p₀ = 10¹⁴×10⁹ = [tex]n_{i}[/tex] = √10²³ = 3.16×10¹¹. The low-level injection applies on the P-side as Δn(-[tex]x_{p}[/tex]) = 10¹⁰ << p₀ and on the N-side Δp([tex]x_{n}[/tex])=10¹² << n₀ = 10¹⁴.

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Alkali carbonates are soluble in water so (NH₄)2CO₃ sodium carbonate and potassium carbonates are soluble in water.

A composite is a material comprised of two or more constituent parts. Examples of molecules are carbon dioxide, freshwater, and table salt. a substance produced by the chemical joining of two or three dissimilar components. Examples of compounds are salt (NaCl), which is made up of chloride and sodium atoms, and water (H2O), which would be made up of hydrogen and oxygen atoms.

When a group of atoms unite to form a pure material, a compound is created. These can be reduced to their individual atoms. Atoms from the reactants interact during chemical reactions to create new compounds. Reactants are the species that are reacting, while products are the results of the reaction.

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the concentration of Na after the two solutions are mixed together is 0.662 M.

1. Volume of Na2CrO4 = 132.4 ml = 0.1324 L.

2. Concentration of Na2CrO4 = 2.50 M

3. Volume of AgNO3 = 125 ml = 0.125 L

4.  Concentration of AgNO3 = 2.50 M.

Calculation :-

1. Moles of Na2CrO4 =  Molarity * Volume in L.

Moles of Na2CrO4= 2.50 * 0.1324 = 0.331 mol

2. Moles of AgNO3 = Molarity * volume in L

Moles of AgNO3 = 2.50 * 0.125 = 0.3125 mol

Solution :

the reaction of aqueous silver nitrate (AgNO3) with aqueous sodium chromate (Na2CrO4) to form solid silver chromate (Ag2CrO4) and aqueous sodium nitrate (NaNO3).

2 AgNO3(aq) + Na2CrO4 (aq) \rightarrow Ag2CrO4(s) + 2 NaNO3(aq).

Above balanced reaction shows that,

2 moles of AgNO3 reacts with 1 mol Na2CrO4.

Let,  0.3125 mol AgNO3 reacts with x mol Na2CrO4.

x = 0.3125 / 2

x = 0.1563 mol Na2CrO4.

Now,

1. Balanced reaction shows that,

2 mol AgNO3 forms 2 mol NaNO3.

So, 0.3125 mol AgNO3 forms 0.3125 mol NaNO3.

So,  moles of NaNO3 = 0.3125 mol.

As 1 molecule of NaNO3 gives 1 Na^+ ion.

0.3125 mol NaNO3 gives 0.3125 mol Na^+ ions...... A

Aslo,

2. remaining moles of Na2CrO4 = total moles - used moles

Remaining moles of Na2CrO4 = 0.331 - 0.1563 = 0.1748 mol.

1 molecule of Na2CrO4 gives 2 Na^+ ions.

So, 0.1748 moles of Na^2+ ions gives 0.3496 mol Na^+ ions............ B

3.So, total moles of Na^+ ions= 0.3496 + 0.3125......(from A and B)

Total moles of Na^+ ions = 0.662 mol.

So, concentration of Na^+ ions = 0.662 M.

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AlCl3 is the answer.

As strong acid-strong base salts, NaCl and MgCl2 are both neutral.

Since NH4Cl is a weak base-strong acid salt, it is also acidic. AlCl3 is, nevertheless, a stronger acid than NH4Cl.

Neither acids nor bases can be found in neutral substances. Accordingly, neutral substances have an equal number of these ions. An acid has hydrogen ions, a base has hydroxyl ions, etc. Water is the most typical example of a neutral substance. Both acidic and basic properties are absent from water.

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Explanation:

The 18th-century chemist Antoine Lavoisier and his wife Marie-Anne put fruit into a glass container, and then they sealed it. After weighing the fruit and container, they left it in a warm place for a few days. The fruit decayed, and there was condensation inside the glass and gas in the container. Lavoisier and his wife weighed the decayed fruit and the container again. The weight was the same. What scientific principle did the Lavoisier's experiment support?

In aqueous solutions, excess hydrogen ions bind to nearby water molecules, so it is generally considered more accurate to write h (aq) as H₃O (aq) then name of the H₃O ion is hydronium ion

The hydrogen ion in aqueous solution is no more than proton and a bare nucleus although it carries only a single unit of positive charge and this charge is concentrated into a volume of space that is only about a hundred million as large as volume occupied by smallest atom in case of water this will be the lone pair electron of the oxygen atom and the tiny proton will be buried within the lone pair and will form a shared electron bond with it and creating a hydronium ion means H₃O⁺ and here H₂O is the base and the product H₃O⁺ is the conjugate acid of water

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