Calculate the amount of heat that must be absorbed by 10. 0 g of ice at –20°c to convert it to liquid water at 60. 0°c. Given: specific heat (ice) = 2. 1 j/g·°c; specific heat (water) = 4. 18 j/g·°c; δhfus = 6. 0 kj/mol.

1) Assuming that only single bonds are formed by group 4A(14) elements, the shape of a central atom of group 14 is tetrahedral.

The general electronic configuration of group 14 elements is ns²np² and it is shown in box diagram in the attached image. When one electron is excited, it goes in vacant p-orbital and the p and s-orbital is half filled. It is shown in attached image.

When the another atoms are filled in the half-fiiled orbital, it forms sp³ hybridisation and its shape is tetrahedral.

Therefore, the shape of central atom of group 14 is tetrahedral.

2) Assuming that only single bonds are formed by group 4A(14) elements, the shape of a central atom of group 15 is pyramidal.

The general electronic configuration of group 15 element is  ns²np³ and its box diagram is already shown in the image. When atoms are filled, it goes in p-orbital and pair of electron acts as a lone pair. Due to this lone pair, lone pair-bond pair repulsion is occurred and the geometry of the central atom is pyramidal.

Therefore, the shape of central atom of group 15 is pyramidal.

3) Assuming that only single bonds are formed by group 4A(14) elements, the shape of a central atom of group 16 is bent.

The general electronic configuration of group 16 is ns²np⁴ and its box diagram is shown in the attached image. There are two electron pairs which acts as a lone pair and another two orbitals are filled by another atom. When they are filled, it shows lone pair-lone pair, lone pair-bond pair and bond pair-bond pair repulsion. Therefore, they are come closer to each other and forms bent shape.

Therefore, the shape of the central atom of group 16 is bent shape.

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The maximum temperature of the water after mixing is 38.51°C

Heat values is derived from the equation:

  q = mcΔT

where

q = heat ( J)

m= mass ( kg)

c = specific heat capacity

ΔT = change in temperature

T2 = final temperature

T1 = initial temperature

  M of H2O × c × ( T1 - T2) = M of H2O × c × ( T2 - T1 )

29.2 g × ( 78.2° - T2 ) = 67.3 × ( T2 - 21.3° )

2283.44 - 29.2 ×T2 = 67.3 × T2 - 1433.49

3716.93 = 96.5 × T2

T2 = 38.51°C

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Note: here is the completed question

Suppose you mix 29.2 g of water at 78.2°C with 67.3 g of water at 21.3°C in an insulated cup. What is the maximum temperature of the water after mixing?

Answer:Lanthanum

Explanation:

Lithium stars with the letter L in the periodic table.

What is lithium?

The chemical element lithium has the symbol Li and the atomic number 3. It is a silvery-white alkali metal that is soft. It is the least dense metal and the least dense solid element under ordinary conditions. Because lithium, like all alkali metals, is very reactive and combustible, it must be stored in a vacuum, inert environment, or inert liquid such as pure kerosene or mineral oil. It has a metallic shine when cut, but damp air quickly corrodes it to a dull silvery grey, then black tarnish. It is never found naturally, but only in (typically ionic) compounds such as pegmatitic rocks, which were historically the primary source of lithium. It is found in ocean water due to its solubility as an ion.

Lithium stars with the letter L in the periodic table. Other such elements are Lead, Lanthanum, Lutetium, etc.

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The fourth quantum number of a 2s² electron is -1/2.

What is quantum number?

Quantum numbers are the collection of numbers used to characterise the position and energy of an electron in an atom.

A quantum number is a value used to describe the energy levels that atoms and molecules have. For the hydrogen atom, an electron has four quantum numbers that define its state and produce solutions to the Schrödinger wave equation.

The quantum numbers are as follows:

n - the primary quantum number, which describes the energy level

l denotes azimuthal or angular momentum. quantum number: defines the subshell ml or m - magnetic quantum number: defines the subshell orbital ms or s - spin quantum number: defines the spin

In your scenario, you must decide which possible values can be ascribed to an electron's fourth quantum number in a 2 s 2 orbital.

The electron's energy level, or shell, is described by the primary quantum number. Because the electron is on the second energy level in this situation, n = 2.

The subshell in which the electron is placed is described by the angular momentum quantum number, l. The angular momentum quantum number for an s-orbital is equal to l = 0.

The magnetic quantum number, m l, specifies the orbital in which the electron can be found.

Because it is dependent on the s-orbital, the magnetic quantum number can only take the value 0.

Therefore ,  fourth quantum number of a 2s² electron is -1/2.

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The number of atoms of hydrogen present in 2.25 moles of cyclohexanol, C₆H₁₂O is 1.63×10²⁵ atoms

First, we shall determine the number of moles of hydrogen present in 2.25 moles of cyclohexanol, C₆H₁₂O. This is shown below

1 mole of cyclohexanol, C₆H₁₂O contains 12 moles of hydrogen, H

Therefore,

2.25 moles of cyclohexanol, C₆H₁₂O, NF₃ will contain = 2.25 × 12 = 27 moles of hydrogen, H

Finally, we shall determine the number of atoms of hydrogen pressnt in 2.25 moles of cyclohexanol, C₆H₁₂O. This can be obtained as follow:

From Avogadro's hypothesis,

1 mole of hydrogen = 6.02×10²³ atoms

Therefore,

27 moles of hydrogen = 27 moles × 6.02×10²³ atoms

27 moles of hydrogen = 1.63×10²⁵ atoms

Thus, we can draw our conclusion that the number of atoms of hydrogen present is 1.63×10²⁵ atoms

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The total number of moles are given by n = 0.25 moles and N=6.022×10²³molecules/mole is the Avogadro number. N is equal to 6.0220 × 10²³ molecules/mole. Therefore, there are 1.51 × 10²³ molecules overall 1.05 × 10²³ molecules.

The International System of Units uses the mole symbol as mol as the unit of material quantity. How many elementary entities of a certain substance are present in an item or sample is determined by the quantity of that material. It is specified that the mole contains precisely 6.022 × 10 ²³ elementary entities.

The term was generally first used by German chemist Wilhelm Ostwald. However, the Latin term moles, which meaning "a mass," is where the word mole ultimately originates, not from German. A comparable term to mole is molecule, it is the diminutive and means "a little mass."

Therefore, there are 1.51 × 10²³ molecules overall 1.05 × 10²³ molecules.

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Fishes typically fall into the trophic levels of 2 to 4.7, while marine mammals fall into the trophic levels of 3 to 5.5 and cephalopods fall into the trophic levels of 3.2.

The place an organism holds in a food chain determines its trophic level. A food chain is a series of living things that consume other living things and may eventually consume themselves. An organism's trophic level is determined by how far down the food chain it is.

A trophic level in an ecosystem is a stage in the food chain or nutrient cycle. The distance a creature is from the start of the food chain, in simple terms, indicates its trophic level.

Thus, the fishes typically fall into the trophic levels of 2 to 4.7, while marine mammals fall into the trophic levels of 3 to 5.5 and cephalopods fall into the trophic levels of 3.2.

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Best describe table sugar is considered a pure substance is Sugar has the same chemical composition throughout

Table sugar is pure sucrose derived from sugar beet or sugar cane and sucrose is the disaccharide consisting of glucose and fructose and it is produced by green plant in the process of photosynthesis and since the chemical composition of sugar is definite and does not vary hence it is pure substance and table sugar refer to standard while white sugar that you see in your cooking baking or cup of tea at home and the scientific name foe table sugar is sucrose

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Based on the half-life of the material, the isotope is radium-226; option D

The half-life of a substance is the time taken for half of the amount of material present in the original sample of the material to decay.

The half-life of materials differs from each other. The half-life may be in millions of years for some materials, whereas for some materials, the half-life could only be in seconds.

The half-life of materials is constant.

Considering the given material;

One-eighth of the mass of the original sample of the radioisotope remains unchanged after 4,800 years.

For one-eight of the material of the isotope to remain, the number of half-lives it has undergone will be;

after one half-life = half of the original sample remains

after two half-lives = one-fourth of the original sample remains

after three half-lives = one-eight of the original sample remains

The half-life of the isotope = 4800/3

The half-life of the isotope = 1600 years

Radium-226 has a half-life of 1600 yers

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When water freezes at [tex]O^{o}[/tex] Celsius. it will release heat.

When the liquid water turns to solid ice we find that water freezes without getting any colder. That's because the latent heat of fusion is being lost from the liquid as it solidifies and the temperature of the water does not fall so quickly

Does freezing water release heat?

When water becomes a solid, it releases heat, warming up its surroundings. This makes freezing an exothermic reaction.

Does water melt or freeze at 0 Celsius?

At temperatures below 32°F (0°C), liquid water freezes.

Thus, when water freezes at [tex]O^{o}[/tex] Celsius. it will release heat.

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The advantage to performing the reaction in methyl ethyl ketone - a solvent with a high boiling point is to carry the reaction in the forward direction by refluxing the set.

Boiling point is defined as the bulk phenomenon. It is the temperature at which the pressure of atmosphere is equal to the pressure of the vapour or vapour pressure.

Since, high boiling point solvent are used during the procedure to reflux the set which help in carrying out the reaction in the forward direction. If we had used low boiling point solvent instead of high all of the solvent evaporated and refluxing of the mixture of reaction to get product for maximum production could not have been possible.

Thus, we concluded that the advantage to performing the reaction in methyl ethyl ketone - a solvent with a high boiling point is to carry the reaction in the forward direction by refluxing the set.

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The metallic bonds and the ionic bonds do involve charged species while the covalent bonds do not involve charged species.

The term bond has to do with the interactions that holds two atoms together. There are different kinds of bonds that we have in chemistry and these include;

The ionic bond involves the transfer of electrons from one atom to another usually from a metal to a non metal. This results in the formation of ions. In the metallic bond, there is a sea of electrons that lies over metallic ions. In the case of the metallic bonds and the ionic bonds, there are charged species that are present in the system.

For the covalent bonds, there is a sharing of electrons in the bond and then many of the compounds that have the covalent bonds are fond to be nonpolar.

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Answer: T2=233K

Explanation:

The pressure and volume change. The combined gas law is always needed for that concept.

P1*V1/T1=P2*V2/T2

Temperature MUST ALWAYS be in Kelvin

T1=90+273=363K

1200*85/363=850*350/T2

T2=233K

Hope this helps! :)

All of the options mentioned above influence the speed of a chemical reaction. Only the molecularity of the reaction doesn't influence the rate of the reaction.

What is a Chemical reaction?

A chemical reaction is a procedure that causes one group of chemical substances to change chemically into another. Chemical reactions are typically defined as changes that only affect the positions of electrons in the formation and dissolution of chemical bonds between atoms, with really no alteration to the nuclei. These changes are frequently captured by a chemical equation. The study of chemical reactions involving unstable and radioactive elements, where both electronic as well as nuclear changes may take place, is known as nuclear chemistry.

Reactants or reagents are the substance(s) or substances that are initially utilised in a chemical reaction. Chemical reactions typically involve a chemical change and produce one or even more products, which typically differ from the reactants in some ways.

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The developing chamber needs to be prepared before adding the tlc plate in order to ensure that the plate is placed in the correct position and to prevent contamination.

What is TLC?

Non-volatile mixtures can be separated using the chromatography technique known as thin-layer chromatography (TLC). A sheet of an inert substrate, such as glass, plastic, as well as aluminium foil, is used for thin-layer chromatography. This substrate is coated with a thin layer of an adsorbent material, typically silica gel, aluminium oxide (alumina), as well as cellulose. The stationary phase refers to this adsorbent layer. A solvent as well as solvent mixture (referred to as the mobile phase) has been drawn up the plate by capillary action after the sample has been placed on the plate. Separation is accomplished because various analytes ascend this same TLC plate at various rates.

The developing chamber should be ready before the TLC plates are added, allowing the chamber time to become saturated with the developing solvent and producing quicker, more consistent results.

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The force that the roller coaster is creating under the top of the hill is A) 30000 N.

It is given that the initial velocity is 20m/s and final velocity is 80m/s and the time is 2s.

The force required to accelerate a mass from 20 m/s to 80 m/s in 2 seconds is given by the equation:

F = (m * (v - u)) / t

where m is the mass of the object, v is the final velocity, u is the initial velocity, and t is the time.

Substituting the values given in the question, we get:

F = (1000 kg x (80 m/s - 20 m/s)) / 2 s

F = 1000 x 30

F = 30,000 N

Hence, the correct option is A) which is 30000N. It is the force generated by the roller coaster at the bottom of the hill.

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He tests multiple hypotheses at a time and He uses identical specimens when completing multiple trials.

The two options are correct B,C.

While experimentation as a whole encompasses this form of research, individual research designs have certain characteristics. The four main design types that are pertinent to user experience design are appropriate in this study, scientific, and developed a semi.

Any randomized experiment may occasionally be referred to as a real experiment. In other cases, the phrase "true experiment" is used to refer to any investigations that have at at one continuous dependent variable and at least one free variables that is experimentally changed. When experiments are also used to determine whether a theory-based idea, axiom, or phenomenon is true, they play a crucial role in the evolution of science.

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Among the following oxides Al2O3 is the most acidic.

An acidic oxide is an oxide that when combined with water gives acid. A basic oxide is an oxide that when combined with water gives off a base. Consider when a substance reacts chemically, both as a base or acid is termed as amphoteric oxide. Neutral Oxide is one that neither has an acidic characteristic nor a basic one.

Acidic oxides are generally those that are electron deficient species or generally those that have the high oxidation number. Considering this Na2O, Li2O, CaO are metallic oxide of s block. These metallic oxides powerful bases, while Al2O3 is metallic oxide of p block which has comparatively more acidic character. Hence, it is the most acidic oxide among all. CO2 is also a strong acid but it is weaker than Al2O3.

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The mass of sulfur 5.6 × 10²² atoms of sulfur is 2.975 gram

The Avogadro law states that an equal volume of the gases at the same temprature and pressure contain the same number of molecule

1 mole = 6.022×10²³ atm

Then the molar mass of sulfur = 32g/mol

That means 1 mole of sulfur is composed of 32 g weight which contain = 6.022×10²³

If 1 mole of sulfur = 32 g = 6.022×10²³

The mass of sulfur that is contained in 5.6 × 10²² atoms of sulfur is

x =  5.6 × 10²² × 32 g /6.022×10²³

x = 2.975 gram

Therefore we can conclude that the mass of sulfur that would have precisely 5.6 × 10²² atom of sulfur is 2.975 gram

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The hydrides of group 5a are NH₃ , PH₃ , AsH₃ , and SbH₃, the arrangement of these from highest to lowest boiling point is SbH₃ > NH₃ > AsH₃ > PH₃

The boiling point is the temperature at which the vapor pressure of any liquid equals the pressure of the gas above it. The boiling point depends on the molecules' intermolecular forces and molecular weight. To arrange the given molecules according to the boiling point, we look at the molecular weight and the intermolecular forces. Due to the high molecular weight SbH₃ shows the highest boiling point. N shows 2nd highest boiling point due to high H-bonding, the least boiling is shown by PH₃.

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b) Ca2 < K < Ar < Cl-

In Isoelectric series ions group contains the same number of electrons.

Here, the ionic radius of Ca2 is 100pm, K is 138pm, Ar is 181pm and Cl- is 184pm.

In option a, Ar has higher ionic radius than k which is incorrect. In option c, cl- higher ionic radius than Ar which is incorrect too. In option d, K has higher ionic radius than Ca2 which results in incorrect. In option e, Cl- has the highest ionic radius among all, which results in incorrect too.

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Based on the equation of the reaction;

The percentage mass of iron in the ore is determined from the net ionic equation of the reaction as follows:

5 Fe²⁺ + MnO₄⁻ + 8H+ ---> 5 Fe³⁺ + Mn²⁺ + 4 H₂O

The mole ratio of the reaction shows that 5 moles of the iron (ii) ion is oxidized by 1 mole of tetraoxomanganate (vii) ion, MnO₄⁻.

The moles of tetraoxomanganate (vii) ion, MnO₄⁻ that reacted with al the iron present in the ore is determined as follows:

Moles of substance = molarity * volume in liters

Moles of tetraoxomanganate (vii) ion, MnO₄⁻ = 0.0281 * 39.42/1000

Moles of tetraoxomanganate (vii) ion, MnO₄⁻ = 0.001108 moles

Moles of iron (ii) ion present in the sample = 0.001108 * 5

Moles of iron (ii) ion present in the sample = 0.00554 moles

Mass of iron (ii) ion present in the sample = 0.00554 * 56

Mass of iron (ii) ion present in the sample = 0.31 g

Percent mass of iron in the ore = 0.31/1.362 * 100%

Percent mass of iron in the ore = 22.8%

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Answer: 4 grams

Explanation:

The weight of one mole of hydrogen gas is 2 grams.

hence,there are 4 grams in 2 moles of hydrogen atom.

Steel is used to create the chassis that forms the skeleton of the car and protects it in the event of a crash.  The glass is transparent and heat resistant.  Paint serves as a protective coating to protect the vehicle from damage.

Steel can be described as a very hard and strong alloy that has a very high strength-to-weight ratio. All these properties can make it a suitable material for car bodies.

In cars, steel is used to form the underlying chassis or cage beneath the car body that creates the skeleton of the vehicle and protects it in a crash. Door beams, body panels, and roofs are created while auto manufacturing is composed of steel on most cars.

Most of the steel is found in the skeletal car body, generally called the “body in white,” which is the foundation of the rest of the vehicle is created.

The types of steel used such as stainless steel, high-strength steel, high or low carbon, or galvanized steel for body panels. These types of steel can be used in the production of several vehicle and engine components.

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H2Se(g) + 402F2(g) ⇒SeF6(g) + 2HF(g) + 4O2(g) is true regarding following points ;

B. the oxidation number of H changes from -1 to +1 we can see as in H2Se changes to 2F.

C. the oxidation number of F changes from -1 to +1 we can see in O2F2 to        

     4O2.

D. the oxidation number of Se changes from -2 to +6 as we can see in H2Se to SeF6.

oxidation number also called oxidation state, is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.

disproportionation reaction is the type of reaction when the compound is converted into 2 oxidation states one of higher and one of lower oxidation state.

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The possibility of the presence of maximum number of electrons in an atom with the quantum numbers n = 5, ℓ = 2, mℓ = -2, ms = +½. is 8.

Generally, n is called principal quantum number and it indicates the energy levels or energy shells in an atom.

While m represent the magnetic quantum numbers and it shows the total number of electron which share these quantum numbers.

When n = 5 for an electron, then the value of l can be l = {0; 1 ; 2 ; 3; 4} and the values of magnetic quantum numbers lie between -l and + l.

When m1 = 1 then l can be {1 ; 2 ; 3; 4} and similarly, the spin quantum number can have values between m(s) = { +1/2, -1/2}

To put it simply, electrons with opposite spin share only one orbital and thus there will be total 8 electrons.

n = 5, l = 1, m1 = 1 and ms = ± 1/2

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Hair samples can be different even when taken from the same person

is true about the human body.

What is Hair samples?

A collection of hair strands known as a hair sample is most frequently taken from a person's head. Hair from the past year is typically present in hair samples. Despite the fact that hair growth varies, 5 inches of hair are typically added in 12 months.

What is physical properties of hair?

Elasticity, stiffness, cross-sectional area, form, density, and static charge are some of these characteristics. These attributes, along with hair's resistance to water and stretching, all affect how it looks on a daily basis.

Hence Hair samples can be different is a correct answer.

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Foods that are high in carbohydrates have the least impact on slowing the body's absorption rate of alcohol.

What is human digestive system?

The digestive system of the human body is made up of the gastrointestinal tract and additional digestive organs (the tongue, salivary glands, pancreas, liver, and gallbladder). In order for food to be absorbed and incorporated into the body, it must first be broken down into smaller and smaller components during digestion. Cephalic, gastric, and intestine phases make up the three

Our body will immediately start absorbing alcohol when you are hungry. However, because alcohol is not soluble in fat, fatty foods effectively create a barrier through which it cannot easily travel. This will greatly slow down alcohol absorption.

Hence, foods that are high in carbohydrates have the least impact on slowing the body's absorption rate of alcohol.

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Physical weathering is caused by the effects of temperature changes on rocks, causing them to break apart. The process is sometimes aided by water.

Abrasion Weather effects such as wind and water break rocks into small pieces. Exfoliated weathered rock expands and fractures when pressure is released from unloading. Frostwedge rock cracks when water freezes and expands. Chemical weathering involves the interaction of rocks with mineral solutions (chemicals), changing the composition of rocks.

Rocks are formed by weathering and erosion that break down existing rocks through physical and chemical processes. Examples of chemical weathering include rust caused by oxidation and acid rain caused by carbonic acid dissolving rocks. Other Chemical Weathering B. Dissolution. Rocks and minerals break down to form soil.

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The skeletal and balanced version of the equation would be [tex]2Na + Ca(OH)_2 --- > 2NaOH + Ca[/tex]

The symbol equation, which was otherwise referred to as skeletal equation in the illustration is an equation that expresses each participating component of a reaction in its symbolic forms.

On the other hand, a balanced equation of a reaction is the equation in which the number of atoms of different elements present in the reactants is equal to the number present in the products. It does not matter if their forms change, however.

Thus, for the equation: sodium + calcium hydroxide → sodium hydroxide + calcium

Symbol of sodium = Na

Symbol of calcium hydroxide = [tex]Ca(OH)_2[/tex]

Symbol of calcium = Ca

The equation then becomes: [tex]2Na + Ca(OH)_2 --- > 2NaOH + Ca[/tex]

The equation has taken into account the number of atoms of different elements in the reactants and the products. It is already a balanced equation.

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