Suppose that Biuret reagent turns purple when it is added to an unknown substance. What can you conclude about the substance?

Answer:

Explanation:

i’m not sure but I think it’s 7648%

Answer:

D

Explanation:

The nuclear model of the atom was proposed by Ernest Rutherford.

In his submission, the atom consists of a dense positive nucleus with electrons moving round this nucleus as planets move round the sun. He likened his model to the solar system. The nucleus is at the center of this system just as the sun is at the center of the solar system.

Answer:

D.The nuclear model describes the atom as a dense, positive nucleus surrounded by a cloud of negative electrons.

Explanation:

As air undergoes conduction better in tile than in carpet, hence a carpeted floor feel warmer to bare feet than tile or wood even though all surfaces are the same temperature.

Conduction is defined as a process as a means of which heat is transferred from the hotter end of the body to it's cooler end.Heat flows spontaneously from a body which is hot to a body which is cold.

In the process of conduction,heat flow is within the body and through itself.In solids the conduction of heat is due to the vibrations and collisions of molecules while in liquids and gases it is due to the random motion of the molecules .

When conduction takes place, heat is usually transferred from one molecule to another as they are in direct contact with each other.There are 2 types of conduction:1) steady state conduction 2) transient conduction.According to the type of energy conduction is of three types:

1) heat conduction

2) electrical conduction

3)sound conduction

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Moles of [tex]H_2O[/tex] ,

[tex]n_{H_2O}=\dfrac{42}{2\times 1 + 16}=\dfrac{42}{18}\\\\n_{H_2O}=2.33\ moles[/tex]

Moles of acetic acid [tex]HCH_3CO_2[/tex] ,

[tex]n_{A.A}=\dfrac{77}{1 + 12 + 3 + 12 + 16\times 2}=\dfrac{77}{60}\\\\n_{A.A}=1.28\ moles[/tex]

Mole fraction of water :

[tex]M.F_{H_2O}=\dfrac{n_{H_2O}}{n_{H_2O}+n_{A.A}}\\\\M.F_{H_2O}=\dfrac{2.33}{2.33+1.28}\\\\M.F_{H_2O}=0.645[/tex]

Therefore, mole fraction of water in this solution is 0.645 .

Hence, this is the required solution.

Answer:Copper is a chemical element with the atomic number 29, and the chemical symbol Cu. Silver is also found on the periodic chart of elements, and has a chemical symbol of Ag and an atomic number of 47.

Explanation:

Both silver and copper are transition metals of d-block in periodic table they are in the same group and thus shows similar chemical and physical properties.

In periodic table, elements are classified into groups and periods. The horizontal rows are called periods and the vertical columns are called groups.

There are 18 groups and 7 periods in periodic table. Elements of the same group have same number of valence electrons and similar chemical and physical properties.

Silver, copper and gold are in 11th group of periodic table. Thus they have 9 valence electrons and exhibit similarity in properties. All these metals are good conductors and are used in electrical and optoelectronic devices.

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Answer:

Explanation:

Since the student fills up the buret with NaOH without rinsing it with small amount of NaOH , the water that is remaining stuck with the walls of the buret will dilute the solution of NaOH and it will result in lowering the morality of the solution . The molar concentration of the NaOH will no longer remain the same . It will lead to wrong calculation and hence wrong result.

The washing of burette in titration with NaOH solution results in the maintaining the concentration of the NaOH in the solution and allows the correct calculation of the molarity.

The titration has been the reaction of the acid with the base resulted in the formation of salt and water and had the neutralization reaction.

The molarity of the base has been used in the analysis of the acid concentration on the neutralization reaction.

The skipping of the step of washing with NaOH resulted in the altering in the concentration of the NaOH with the stuck water on the walls of the burette, and thereby resulted in wrong calculation.

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Answer:

B

Explanation:

The entropy will increase as the ice melts.  While in a solid state (ice) entropy is lower because the molecules are ordered and in a set position.  As the ice melts the molecular have a larger area to roam.  When going from a solid state to a liquid state, entropy rises.  When going from a liquid state to a gaseous state, entropy rises.

Answer:

Problem

Explanation:

The given statement is a problem. It states the problem that the house of the speaker has been undergoing with. This problem gives rise to the Hypothesis in which the 'why' question is asked. The reason of the crumbling of the wood is stated in the hypothesis. Any reason placed of the happening of the event is stated to be hypothesis.

The correct answer is Migrating farther into the sea

Explanation:

The Adálie penguins rely on ice sheets to obtain food as the krill they feed on is only found underside of the ice. This implies as the Antarctic sea ice melts Adálie penguins need to look for new places to find krill as if there are no ice sheets there are no krill for these penguins. Due to this, it is likely these penguins are forced to migrate or move farther into the sea to survive because it is likely in these zones there are ice sheets and therefore places where they can find krill. Despite this, this process might lead to a significant decline in the population of penguins due to the competence for food and the process of migration itself. Thus, the one that would help Adáline penguins to survive during the melting of Antarctic sea ice is migrating farther into the sea.

Have a nice day!   :)

The Adálie penguins feed on krill that live on the underside of ice sheets. Adálie penguins survive during the melting of Antarctic sea ice help migrating farther into the sea. Therefore, option A is correct.

The term migration is defined as the movement of either people or animals from one area to another.

The Adálie penguins rely on ice sheets for food because the krill they eat is only found on the underside of the ice. As a result, it is likely that these penguins are forced to migrate or move further into the sea to survive.

Regardless, this process may result in a significant decline in penguin population due to food competence and the migration process itself.Thus, the one that will assist Adáline penguins in surviving during the melting of Antarctic sea ice is migrating deeper into the sea.

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Your question is incomplete,most probably your question was

The Adálie penguins feed on krill that live on the underside of ice sheets. Which of the following would help Adálie penguins survive during the melting of Antarctic sea ice? Migrating farther into the sea Breeding during summer months Growing strong toe nails to grip ice Spending more time raising their young

Answer:

Ecological islands is just a terminology used, since it isn't surrounded by water like an actual island, instead, it's something isolated from other things, which is the same thing as an island in a way:

Island (geographical) - Land isolated from bigger "main" land masses by water.

Island (ecological) - Land which contains certain isolated features (habitat, plants, etc.).

Explanation:

An ecological island is an area of land, isolated by natural or artificial means from its surrounding land while geographical islands are a body of land surrounded by water.

An ecological island refers to an area of land which is not necessarily an actual island but isolated by natural or artificial means from the surrounding land. A natural micro-habitat exists on sich lands amidst a larger differing ecosystem.

In artificial ecological islands, all non-native species are eradicated, native species are reintroduced and nurtured, and the natural or artificial border is maintained to prevent the reintroduction of non-native species.

A geographical island is a body of land surrounded by water. Continents are also surrounded by water as they are so big but they are not considered islands. Islands may be categorized as either continental or oceanic.

There are so many islands in the lakes, oceans, and rivers around the world. They vary in climate, size, and the types of organisms that inhabit them.

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Answer:

2.35 x 10²⁰ atoms Ga

Explanation:

After converting from mg to g, use the molar mass as the unit converter to convert to moles. Then using Avogadro's number, 6.022 x 10²³ convert from moles to atoms of Ga.

[tex]27.2mgGa*\frac{1g}{1000mg} *\frac{1 mol Ga}{69.72gGa} *\frac{6.022*10^2^3 atoms Ga}{1 molGa} = 2.349 * 10^2^0 atoms Ga[/tex]

Then round to 3 significant figures = 2.35 x 10²⁰ atoms Ga.

The number of atoms in 27.2 mg sample of Ga is 2.35 × 10²⁰ atoms

From the question, we are to calculate the number of atoms in a 27.2 mg sample of Ga.

First, we will determine the number of moles of Ga present

Using the formula,

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

Mass = 27.2 mg = 0.0272 g

Molar mass = 69.72 g/mol

Then,

[tex]Number\ of\ moles \ of\ Ga = \frac{0.0272}{69.72} [/tex]

[tex]Number\ of\ moles \ of\ Ga = [/tex] 0.000390132 moles

Now, for the number of atoms present

From the formula

Number of atoms = Number of moles × Avogadro's constant

Then,

Number of Ga atoms = 0.000390132 × 6.022×10²³

Number of Ga atoms = 2.35 × 10²⁰ atoms

Hence, the number of atoms in 27.2 mg sample of Ga is 2.35 × 10²⁰ atoms

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Answer:

[tex]0.326\frac{N}{cm^2}[/tex]

Explanation:

Hello.

In this case, considering that 1 atm equals 1.01 kPa, we can compute the pressure in kPa first as shown below:

[tex]2.25atm*\frac{1.01kPa}{1atm} =3.26kPa[/tex]

Now, we convert kPa to Pa, considering 1 kPa equals 1000 Pa:

[tex]3.26kPa*\frac{1000Pa}{1kPa}=3260Pa[/tex]

Now, since Pa is equal to N/m², and 1 m equals 100 cm, the pressure in newton per square centimeter turns out:

[tex]3260\frac{N}{m^2}*(\frac{1m}{100cm})^2 \\\\0.326\frac{N}{cm^2}[/tex]

Best regards.

Answer:

The correct answer is: K'= 0.033.

Explanation:

The formation of HI from H₂ and I₂ is given by:

H₂ + I₂ → 2 HI      K= 29.9

The decomposition of HI is the reverse reaction of the formation of HI:

2 HI → H₂ + I₂     K'

Thus, K' is the equilibrium constant for the reverse reaction of formation of HI. It is calculated as the reciprocal of the equilibrium constant of the forward reaction (K):

K' = 1/K = 1/(29.9)= 0.033

Therefore, the equilibrium constant for the decomposition of HI is K'= 0.033

Answer:

Near the boiling point of the solvent

Explanation:

The process of recrystallization is hinged on the fact that the amount of solute that can be dissolved by a solvent increases with temperature. The process involves creation of a solution by dissolving a solute in a solvent at or near its boiling point.  At the boiling point of the solvent, the solute has a greater solubility in the solvent; not much volume of  the hot solvent is required to dissolve the solute.

Before the solution is later cooled, you can now filter out insoluble impurities from the hot solvent. The quantity of the original solute drops appreciably because impurities have been removed. At this lower temperature, the solution becomes saturated and the solute can no longer be held in solution hence it forms pure crystals of solute, which can be recovered.

Recrystallization must be carried out using the proper solvent. The solute must be relatively insoluble in the solvent at room temperature but more soluble in the solvent at elevated temperature.

Answer:

The orbitals on the carbon atom are hybridized; the bonds result from overlap of carbon hybrid orbitals with hydrogen atomic orbitals

Explanation:

In the formation of methane, carbon atoms are sp3 hybridized. One s orbital in carbon mixes with three p orbitals of carbon to yield a set of four sp3 orbitals which bonds to four hydrogen 1s orbitals by sigma bonds.

The molecule is tetrahedral with a bond angle of 109.5 degrees

Answer:

b. No

Explanation:

The question above is related to "The Law of Conservation of Mass." This law states that mass is neither created nor can it be destroyed. Even if a particular matter will be mixed with another substance or it undergoes chemical reaction, the mass of the matter will remain the same. Even with a change in phase, the mass of the matter will remain the same.

Answer:

helium

Explanation:

remaining three are efficient gas

Among the options given below, helium is not an efficient greenhouse gas. Thus, the correct option for this question is A.

Greenhouse gases are those gases that significantly allow solar radiation in order to enter but prevent the escape of heat radiations of longer wavelengths. The names of common greenhouse gases are carbon dioxide, methane, nitrous oxide, CFCs, etc.

According to the context of this question, the presence of these gases in the atmosphere is responsible for the phenomenon of keeping the earth warm. This is known as Greenhouse effect. These gases stimulate the phenomenon of global warming.

Therefore, among the options given below, helium is not an efficient greenhouse gas. Thus, the correct option for this question is A.

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Answer: the % is 99.73 and the mass is 40.986

Explanation:

Answer:

amino acids

Hope this helps:)

Answer:

C: Amino Acids on edge

Explanation:

Answer:

The answer will be 29.4˚C.

Explanation:

Using the formula 5(˚F-32)/9, plug in the numbers and you'll get 29.4˚C.

Answer:

1.14 M

Explanation:

Let's consider the following reaction.

butane ⇄ isobutane

We can use the concentrations at equilibrium to calculate the equilibrium constant.

Kc = [isobutane] / [butane]

Kc = 2.5 / 1.0

Kc = 2.5

If we add 0.50 M of isobutane, we get [isobutane] = 2.5 + 0.50 = 3.0 M.

This will be an initial concentration in an ICE chart.

        butane ⇄ isobutane

I           1.0              3.0

C         +x                -x

E        1.0+x           3.0-x

The equilibrium constant is:

Kc = 2.5 = [isobutane] / [butane]

2.5 = (3.0-x) / (1.0+x)

2.5 + 2.5x = 3.0-x

x = 0.14

The equilibrium concentration of butane is:

[butane] = 1.0+x = 1.14 M

Extremophiles are bacteria, archaea, as well as eukarya across all three domains of life. Cells make up every organisms.

Extremophiles contain bacteria, archaea, as well as eukarya from all three domains of life.

Any organic, biological system which works as a separate entity was referred to as an organism.

Extremophiles are organisms that can survive in harsh settings, such as those with high temperatures, radiation, salt, or pH levels. In the planet's evolutionary development, several creatures have been ecologically dominating.

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Answer:

red

Explanation:

blue litmus paper turns red under acetic conditions and red lettuce paper turns blue under basic and alkaline conditions with the color change occurring over the PH range the neutral litmus paper is purple

The answer is red.

took the test.

Answer:

Even though oxygen is transported via the blood, you may recall that oxygen is not very soluble in liquids. A small amount of oxygen does dissolve in the blood and is transported in the bloodstream, but it is only about 1.5% of the total amount. The majority of oxygen molecules are carried from the lungs to the body’s tissues by a specialized transport system, which relies on the erythrocyte—the red blood cell. Erythrocytes contain a metalloprotein, hemoglobin, which serves to bind oxygen molecules to the erythrocyte (Figure 1). Heme is the portion of hemoglobin that contains iron, and it is heme that binds oxygen. One hemoglobin molecule contains iron-containing Heme molecules, and because of this, each hemoglobin molecule is capable of carrying up to four molecules of oxygen. As oxygen diffuses across the respiratory membrane from the alveolus to the capillary, it also diffuses into the red blood cell and is bound by hemoglobin. The following reversible chemical reaction describes the production of the final product, oxyhemoglobin (Hb–O2), which is formed when oxygen binds to hemoglobin. Oxyhemoglobin is a bright red-colored molecule that contributes to the bright red color of oxygenated blood.

Hb + O2 ↔ Hb − O2

Answer:

The GCF of 18 and 30 is 6