Which answer below correctly identifies the type of change and the explination for the boiling of water

Answer:

ionic bonds also called electrovalent bonds areee bonds that exist two metals.It is an electrostatic attraction between positive and negative ions in a Crystal lattice.

Explanation:

examples of elements with this bond are

hydrogen chloride

copper oxide

potassium bromate

Answer: C.

Explanation:

This is called entropy I believe. (it wouldn't let me answer before)

Answer:

0.8M

Explanation:

Given parameters:

Number of moles of KNO₃  = 0.2mol

Volume of KNO₃ = 250mL

Unknown:

Molarity of the solution  = ?

Solution:

The molarity of a solution is the number of moles in a given volume of a solution;

         Molarity  = [tex]\frac{number of moles }{volume}[/tex]

 We need to convert the given volume to L;

                1000mL  = 1L

        250mL will give  250 x 10⁻³L = 0.25L

So;

        Molarity  = [tex]\frac{0.2}{0.25}[/tex]   = 0.8M

Answer:

0.8 M

Explanation:

The formula is mol divided by liters. Converting 250 ml to .25 liters is important. Dividing .2 by .25 gets the answer. (I swear it’s right but it’s graded wrong so take this with a grain of salt)

Answer:

When an electron temporarily occupies an energy state greater than its ground state, it is in an excited state. An electron can become excited if it is given extra energy, such as if it absorbs a photon, or packet of light, or collides with a nearby atom or particle.

Explanation:

Hope this helps.

Have a good night ma´am/sir.

Be safe!

Answer:

As it is given that

[tex]activity=\lambda= 100\\[/tex]

[tex]Number~of ~counts=100/second\\[/tex]

Using formula

[tex]ln(\frac{N}{N_o})=-\lambda\cdot t\\\\[/tex]

or

[tex]-\frac{ln(\frac{N}{N_o})}{\lambda}= t\\\\[/tex]

where [tex]N=\frac{N_o}{3}[/tex]

[tex]-\frac{ln(\frac{1}{3})}{100}= t\\\\\-\frac{-1.0986}{100}=t\\\\[/tex]

[tex]\frac{1.0986}{100}=t\\1.0986\cdot 10^{-2}seconds=t\\[/tex]

Answer:

Final volume=V₂ = 216.3 mL

Explanation:

Given data:

Initial volume = 120.0 mL

Initial temperature = -12.3 °C (-12.3 +273 = 260.7 K)

Final volume = ?

Final temperature = 197.0 °C (197+273 = 470 K)

Solution:

We will apply Charles Law to solve the problem.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume  

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

V₂ = V₁T₂/T₁

V₂ = 120 mL × 470 K /260.7K

V₂ = 56400 mL.K /260.7K

V₂ = 216.3 mL

Answer:

(a)Double Replacement

(b)Double Replacement

(c)Single replacement

(d)single replacement

(e) synthesis

Answer:

144 g of phosphorus contain 4.65 moles.

Explanation:

Given data:

Mass of phosphorus = 144 g

Number of moles = ?

Solution:

Formula:

Number of moles = mass/ molar mass

Molar mass of phosphorus is 31 g/mol

Now we will put the values in formula.

Number of moles = 144 g/ 31 g/mol

Number of moles = 4.65 mol

Thus, 144 g of phosphorus contain 4.65 moles.

The energy related to the change of state represented by the model is  atoms gain energy as a solid changes to a liquid. Thus option A is correct.

Energy is defined as the quantitative property that is imparted to a body or a physical system and is visible in the performance of work as well as in the form of heat and light.

It can also be defined as ability to perform work.

There are basically nine types of energy:

There are two more forms of energy.

In terms of atomic randomness, the gas contains atoms with extremely high kinetic energies. Atoms in the solid are only vibrating where they should be. As a result, for a gas to become a solid, some energy must be lost within the atom.

Thus, the energy related to the change of state represented by the model is  atoms gain energy as a solid changes to a liquid. Thus option A is correct.

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Answer: Option A

Explanation: took the test

Explanation:

Anions have a negative charge resulting from the gain of one or more electrons to become stable.

Cations have a positive charge due to the loss of two or more electrons in order to become stable or have a noble gas configuration.

Hope this helps you

Answer:

I think its b

Explanation:

Answer:

4.52×1000=4520

Explanation:

4.52*1000=4520

Answer: median :4.44 mean :4.11

Explanation:

i did test on Edge

Answer:

they will repel each other

Explanation:

When these two are brought close to one another they will repel each other. This is similar to what happens with magnets, when two objects share the same polarity one object will create a repulsive force upon the second object and push it away. This repellent force is caused by an electric field from the same charged electrons in the atoms of the object. Since in this case both the glass rod and the pinwheel have a negative charge they will repel each other when they come into proximity of one another.

Answer:

a plus sign: +

Explanation:

a plus sign is used to separate one reactant or product from another

Answer:

(Chemical Formulas test)

1.Which formula contains a metal and a nonmetal?

answer:(MGO)

2.Which formula represents a covalent compound?

answer:(H2O2)

3.In the formula for water (H2O), what does the lack of a subscript after the O indicate? answer:(There is one oxygen atom in the compound.)

4.What symbol is used to separate the products from each other or the reactants from each other in a chemical reaction?answer: (A PLUS SIGHN)

5.Which option is a covalent compound?

answer:(NO2)

Explanation:

Took the Test and got 100% thank me later

Answer:

Inertia

Explanation:

Inertia is the tendency of an object to resist a change in motion. Newton's First Law of Motion is also called the law of inertia. A full aquarium is harder to move than an empty one because the law of inertia.

Answer:

Any element placed in a flame will change its color. Atoms are made of positively charged nuclei, about which negatively charged electrons move according to the laws of quantum mechanics. Quantum mechanics constrains them to appear in various distinct patterns, called orbitals. (Orbitals are a lot like planetary orbits, but blurrier, so that you're never quite sure just where the electrons are.)

Left on their own, the electrons of an atom tend to relax into orbitals that leave the atom with the lowest possible energy--its ground state. Putting atoms into a flame, though, adds energy to the looser electrons farthest from the nucleus and pushes them into other orbitals. Eventually, these excited electrons drop back to where they ought to be, and in so doing, they release the energy they stored up as particles of light, called photons.

Explanation:

Answer:

the types of minerals in the rock

Answer:

C

Explanation: I took the test and got it right (first person is right)

(D) At equilibrium, the concentration of the products will be much higher than the concentration of the reactants.

Answer:

Work done = 664.69 J

Explanation:

Given data:

Work done = ?

Initial volume = 13.43 L

Final volume = 6.87 L

Pressure = 1.91 atm

Solution:

work done = W = -PΔV

ΔV = V₂- V₁

work done = w = -P(V₂- V₁)

Now we will put the values in formula.

W = - 1 atm (6.87 L - 13.43 L)

W = - 1 atm (-6.56 L)

W = 6.56 atm.L

atm.L to joule:

6.56 atm.L × 101.325 J / 1L.atm

664.69 J

Answer:

The amino sequence of an octapeptide can be determined by :

i.Amino acids present in the peptide

ii.By the behaviour shown by the treatment of these material with different biological and chemical reactions

As shown ammonium was released from the peptide,which shows that the peptide contains either Asn or Gln.

As there is presence of Asp in the amino acid analysis which indicates that the octapeptide contains Asp.

Acid hydrolysis hydrolyzes the peptide bonds which yields a Ala-Val  which is the result of partial acid hydrolysis.

Chymotrypsin is on the C-terminal side of the aromatic amino acids Phe, Tyr, and Trp. The peptide has Tyr which indicates that  the two present tetrapeptides after chymotrypsin treatment are fourth and eighth amino acids i-e N--Tyr-C and Tyr as the fourth amino acid and Ala-Val somewhere in the octapeptide

As Arg is only present on the C terminal side  of the Trypsin cleavage therefore Arg must be the second or the sixth amino acid for the two dipeptides to form as a result of arginine treatment of a tetrapeptide

Cyanogen bromide cleaves on the C-terminal side of Met residues. For free Tyr to be produced from cyanogen bromide treatment of one of the tetrapeptides, Met must be either the third or seventh amino acid. Because Ala was present in both tetrapeptides, Ala must be either the first or fifth amino acid, present in the same tetrapeptide as Arg and Met,i-e N.-Tyr-C and Ala-Val somewhere in the octapeptide and Ala-Arg-Met as the first, second, and third or fifth, sixth, and seventh amino acids and Tyr as the fourth amino acid.

One of the tetrapeptides contains Ala-Val as its second and third amino acids and Asn as its N-terminal amino acid. Therefore two combinations are possible as below

N-Asn-Ala-Val-Tyr-Ala-Arg-Met-Tyr-C or N-Ala-Arg-Met-Tyr-Asn-Ala-Val-Tyr-C

Answer:

The amino aciid sequence of an octapeptide can be determined from the amino acids that are present in the peptide and from the results of different chemical and biological treatments.

One equivalent of ammonium was released fro the peptide, indicating that the peptide contains either Asn or Gln. The presence os Asp in the amino analysis indicates that the octapeptide contains Asn.

A) Acid hydrolysis hydrolyzes peptide bonds. The dipeptide Ala-Val is obtained by partial acid hydrolysis. The indicates that Ala-Val is present in the peptide

B) Chymotrypsin cleaves on the C-terminal side of the aromatic amino acids. Phe, Tyr, and Trp. The peptide contains only Tyr. The presence of tetrapeptides after the treatment of ohymotrypsin indicates that Tyr is the fourth and eighth amino acids.

N-Tyr-C and Tyr present as the fourth amino acid. in constrast, Ala-Val is present in the octapeptide

C) Trpsin cleaves on the C-terminal side of Arg and Lys residues. only Arg is present in the octapeptide. Arg must be the second or sixth amino acid, for two dipeptide to be formed from arginine during the treatment of one tetrapeptide.

D) Cyanogen bromide cleaves on the C-terminal side of Met residues. For free Tyr to be produced from cynogen bromide treatment of one of the tetrapeptides, Met must be either the third or seventh amino acid. Because Ala is present in both tetrapeptides, Ala must be either the first or fifth amino acid, present in the same tetrapeptide as Arg and Met.

In addition, presence of N-...-Tyr-C and Ala-Val in the octapeptide and Ala-Arg-Met as the first, second, third or fifth, sixth or seventh amino acids and Tyr as the fourth amino acid.

E) One of the tetrapides contains Asn as its N-terminal amino acid, and Ala-Val as its second and third amino acids. Two octapeptides are possible from this peptide analysis.

The amino acid sequence of the octapeptide is the following:

N-Asn-Ala-Val-Tyr-Ala-Arg-Met-Tyr-C:

N-Ala-Arg-Met-Tyr-Asn-Ala-Val-Tyr-C:

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Explanation:

Number of molecules: 4.30×10²⁵

We need to find out the total number of moles.

Now, as per Avogadro's law, 6.02×10²³ of anything (Avogadro's number) constitutes a unit called one mole. Just like 12 is a dozen, 6.02×10²³ is a mole.

If you were given 24 bananas and you had to find out the number of dozens, you would divide the total number of bananas (24) by the number of bananas in one dozen (12).

We do exactly the same here: divide the total number of molecules (4.30×10²⁵) by the number of molecules in one mole (6.02×10²³) to get the number of moles.

4.30×10²⁵ / 6.02×10²³ = number of moles

Solving, we get number of NH3 moles = 71.4 which is your final answer!

Hope this helps :D

The hydronium ion concentration [H₃O⁺]=7.826 x 10⁻⁶

In general, the weak acid ionization reaction  

HA (aq) ---> H⁺ (aq) + A⁻ (aq)  

Ka's value  

[tex]\large {\boxed {\bold {Ka \: = \: \frac {[H ^ +] [A ^ -]} {[HA]}}}}[/tex]

Reaction

HCN(aq) + H₂O(l) ⇌ H₃O⁺(aq) + CN⁻ (aq)

0.125

x                                   x               x

0.125-x                         x               x

[tex]\tt Ka=\dfrac{[H_3O^+][CN^-]}{[HCN^-]}[/tex]

[tex]\tt 4.9\times 10^{-10}=\dfrac{x^2}{0.125-x}\approx \dfrac{x^2}{0.125}\\\\x^2=6.125\times 10^{-11}\\\\x=7.826\times 10^{-6}[/tex]

Answer:

Ar

Explanation:

Chlorine has an atomic number of 17. That means that it has 17 protons and 17 electrons, thus being electrically neutral. When it gains 1 electron to form the chloride ion, the total number of electrons is 17 + 1 = 18.

Argon is a noble gas with an atomic number of 18, that is, it has 18 protons and 18 electrons.}

Then Cl⁻ has the same number of electrons as Ar.

Answer:

See explanation

Explanation:

A coin is money made from metal stuff. Common coinage metals are copper, silver, nickel etc.

One consideration in coin production is the density of the coin. A coin of less density will have lesser mass and occupy a lesser volume. This makes it easier to carry the coin around.

Coins should therefore be made of low density metals so that they can easily be carried about.

C.

centi- is essentially 10^2 of one meter.

If you had 100m, multiplying 100 by 10^2 (or 100) would give you 10000 cm.