How is the kinetic energy of the particles of a substance affected during a phase change?
A.) Kinetic energy increases during exothermic changes and decreases during endothermic changes.
B.) Kinetic energy decreases during exothermic changes and increases during endothermic changes.
C.) Kinetic energy does not change, but the potential energy does.
D.) Kinetic energy changes in the opposite way that the potential energy changes.

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{4 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 6.644518...[/tex]

We have the final answer as

Hope this helps you

Hi

i hope this helps

Answer:

The Greek atom theory

Explanation:

The concept of the Greek atomos theory is an indivisible particle of matter, goes back to ancient Greece and a man named Democritus held that all matter could be subdivided only until some finite particle was reached.

Answer:

Explanation:

The lewis structure (indicating all the atoms and patterns provided as hint in the question) of glycine can be seen in the attachment below. While the chemical structure of glycine can be seen below

         H

          |

H₂N - C - C =O

          |      \

         H      OH

The structure (of glycine) above provides a "fair idea" of how the lewis structure will be.

Answer:

mercury

Explanation:

Answer: Peer-reviewed journal article is the most useful because the information in them had been carefully scrutinized and aproved by people who are experts in that particular field.

Answer:

C. potential energy

Explanation:

got 100 on edg

Answer:

law of conservation of mass

Explanation:

According to the law of conservation of mass, mass is neither created nor destroyed.

This is actually the law that guides the balancing of chemical reaction equations.

On the left side we have four atoms of hydrogen and two atoms of oxygen. Exactly the same number of atoms of each element is seen on the right hand side in accordance with the law of conservation of mass.

Answer:  B. [tex]125\ cm^3[/tex].

The volume of the given object = [tex]125\ cm^3[/tex]

Explanation:

Given : Dimensions of an object : 5 cm x 5 cm  x 5 cm [ it is a cube with all equal sides]

Formula to find the volume of a cube = [tex](side)^3[/tex]

[tex]=5^3\ cm^3=125\ cm^3[/tex]

Hence, the volume of the given object = [tex]125\ cm^3[/tex]

Therefore , the correct option is B. [tex]125\ cm^3[/tex].

Answer:

1. 9.45 g

2. 66.9%

Explanation:

The balanced equation for the reaction is given below:

Cu(s) + 4HNO3(aq) —> Cu(NO3)2(aq) + 2NO2(g) + 2 H2O(l)

Next, we shall determine the mass of Cu that reacted and the mass of Cu(NO3)2 produced from the balanced equation. This can be obtained as follow:

Molar mass of Cu = 63.5 g/mol

Mass of Cu from the balanced equation

= 1 × 63.5 = 63.5 g

Molar mass of Cu(NO3)2 = 63.5 + 2[14 + (3×16)]

= 63.5 + 2[14 + 48]

= 63.5 + 2[62]

= 63.5 + 124

= 187.5 g/mol

Mass of Cu(NO3)2 from the balanced equation = 1 × 187.5 = 187.5 g

Summary:

From the balanced equation above,

63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.

1. Determination of the theoretical yield of Cu(NO3)2. This can be obtained as follow:

From the balanced equation above,

63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.

Therefore, 3.20 g of Cu will react to produce = (3.20 × 187.5) / 63.5 = 9.45 g of Cu(NO3)2.

Thus, the theoretical yield of Cu(NO3)2 is 9.45 g.

2. Determination of the percentage yield of Cu(NO3)2.

Actual yield of Cu(NO3)2 = 6.32 g

Theoretical yield of Cu(NO3)2 = 9.45 g.

Percentage of the Cu(NO3)2 =?

Percentage yield = Actual yield /Theoretical yield × 100

Percentage yield of Cu(NO3)2 = 6.32/9.45 × 100

Percentage yield of Cu(NO3)2 = 66.9%

The theoretical yield of Cu(NO₃)₂ is 9.445 g

The percent yield of Cu(NO₃)₂ is 66.91%

From the question.

We are to determine the theoretical yield of Cu(NO₃)₂,

First and foremost, we will write the balanced chemical equation for the reaction properly

The balanced chemical equation for the reaction is

Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)

This means

1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂, 2 moles of NO₂ and 2 moles of H₂O

To determine the theoretical yield of Cu(NO₃)₂,

First, we will determine the number of moles of Cu that reacted

Mass of Cu = 3.20 g

Molar mass of Cu = 63.546 g/mol

From the formula

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

∴ Number of moles of Cu = [tex]\frac{3.20}{63.546}[/tex]

Number of moles of Cu present = 0.050357 moles

The number of moles of Cu that reacted is 0.050357 moles

Since,

1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂

Then,

0.050357 moles of Cu will react with 0.201428 moles of HNO₃ to produce 0.050357 moles of Cu(NO₃)₂

∴ 0.050357 moles of Cu(NO₃)₂ will be produced during reaction

Now, for the theoretical yield of Cu(NO₃)₂  

From the formula

Mass = Number of moles ×  Molar mass

Molar mass of Cu(NO₃)₂ = 187.56 g/mol

∴ Theoretical yield of Cu(NO₃)₂ = 0.050357 × 187.56

Theoretical yield of Cu(NO₃)₂ = 9.445 g

Hence, the theoretical yield of Cu(NO₃)₂ is 9.445 g

For the percent yield of Cu(NO₃)₂

[tex]Percent \ yield = \frac{Actual \ yield}{Theoretical \ yield } \times 100 \%[/tex]

From the question

Actual yield = 6.32 g

But,

Theoretical yield = 9.445 g

∴ Percent yield of Cu(NO₃)₂ = [tex]\frac{6.32}{9.445} \times 100\%[/tex]

Percent yield of Cu(NO₃)₂ = [tex]\frac{632}{9.445}\%[/tex]

Percent yield of Cu(NO₃)₂ = 66.91%

Hence, the percent yield of Cu(NO₃)₂ is 66.91%

Learn more here: https://brainly.com/question/13902065

Answer:

See Explanation

Explanation:

Positional Energy for electron as function of principle energy level (n)

=> Eₙ = -A/n²; A = 2.18x10⁻¹⁸J

Positional Energy for electron in n=2 => E₂ = -2.18x10⁻¹⁸/(2)² = -5.45x10⁻¹⁹J

Positional Energy for electron in n=3 => E₃ = -2.18x10⁻¹⁸/(3)² = -2.42x10⁻¹⁹J

ΔE(n=3→2) = -5.45x10⁻¹⁹J - (-2.42x10⁻¹⁹J) =   -3.03x10⁻¹⁹J

Answer:

So the answer to this question would be C. 400 J

Explanation:

Now for this problem, what is given is a 40 Newtons which would represent the force to be applied to the object, and a distance of 10 meters after the application of the said force. When these two combine, work is done. The unit for work is Joules and this is what we are looking for. The formula to get Joules or for work would be the force applied to the object multiplied by the distance that it travelled after the application of the force. It looks like this

work = force x distance

Joules = Newtons x meter

so let us substitute the variables to their corresponding places

Joules = 40 N x 10 m

Joules = 400 J

IF THIS HELPED YOU PLEASE MARK ME BRAINLIEST! THANKS! :)))))

Answer:

Explanation: Fractional distillation

liquid 1 and 2 have the same color and mass so the answer would be liquid 1 and 2

Explanation:

hope this is helpful

Answer:

[tex]V=23.9mL[/tex]

Explanation:

Hello!

In this case for the solution you are given, we first use the mass to compute the moles of CuNO3:

[tex]n=2.49g*\frac{1mol}{125.55 g}=0.0198mol[/tex]

Next, knowing that the molarity has units of moles over liters, we can solve for volume as follows:

[tex]M=\frac{n}{V}\\\\V=\frac{n}{M}[/tex]

By plugging in the moles and molarity, we obtain:

[tex]V=\frac{0.0198mol}{0.830mol/L}=0.0239L[/tex]

Which in mL is:

[tex]V=0.0239L*\frac{1000mL}{1L}\\\\V=23.9mL[/tex]

Best regards!

Answer:

A

Explanation:

I took a test like this and my teacher said this was right so ye. hopefully I remembered correctly if its wrong im sorry ;C

Answer: A

Explanation: A thunderstorm forms when warm, moist air rises into cold air. Hope this helps. :)

Answer:

1. solute dissolved in solvent makes up a solution.

The concentration in mol L-l (M) = 0.717

Given

12% solution of tetrahydrate magnesium chloride (MgCl₂)

Required

The concentration

Solution

Tetrahydrate magnesium chloride (MgCl₂)⇒MgCl₂.4H₂O

MW = Ar Mg+2. Ar Cl+8. Ar H + 4. Ar O

MW=24.31 + 2 x 35.45 + 8 x 1.01 + 4 x 16

MW=24.31+70.9+8.08+64

MW=167.29 g/mol

12% solution = 12 % m/v = 12 g in 100 ml solution

For 1 L solution :

[tex]\tt \dfrac{1}{0.1}\times 12~g=120~g[/tex]

The concentration in g/L = 120 g/L

Convert grams to moles :

[tex]\tt mol=\dfrac{120}{167.29}=0.717[/tex]

Answer:

H:H

Explanation:

Answer:

The major innovation made from Abacus to the present fifth generation​ is explained below in details.

Explanation:

Industrial Age - 1600

John Napier, a Scottish noble and diplomat consecrated much of his holiday time to the learning of mathematics. He was particularly engrossed in devising methods to aid estimates. His most famous offering was the discovery of logarithms. He listed logarithmic measures on a set of 10 board rods and thus was capable to do multiplication and division by equaling up numbers on the poles. These became recognized as Napier’s Bones.

Answer:

I want to say 10 grams

Explanation:

80 grams is your start

and a half-life is half of that so...

half of 80 ( and or 80/2)

40 grams

then another half is...

half of 40 (and or 40/2)

20 grams

then another half-life is...

half of 20 (and or 20/2)

10 grams

That is 3 half-life of 80 grams

*becareful not to just divide 80 / 3 you will get 26.666 (repeating) that is  incorrect

you want a half of a half of a half

Answer:

D

Explanation:

Answer:

D Atoms are made up of smaller subatomic particles

Explanation:

I just took the quiz, I hope this helps!

The atomic number of this atom : 8

Given

Atomic model (attached)

Required

The atomic number

Solution

To determine the atomic number of an element, we can look at the number of electrons or the number of protons, because

atomic number = number of protons = number of electrons in neutral atoms

While the mass number is the number of neutrons + the number of protons located in the atomic nucleus

The charge of each of these atomic sub particles:

If we look at this atomic model, there are 8 electrons in the shell, consisting of 2 electrons in the first shell and 6 electrons in the second shell (which can also be called valence electrons)

Whereas in the atomic nucleus there are 8 protons and 10 neutrons

Answer:8

Explanation:

Answer:

3

Explanation:

Sodium is not a gas, it is a Alkali Metal. I recommend studying the sections of the periodic table to help remember what each element should be.

Hope this helps.

Answer:

Sentences are where there is a beginning and an end of a section of a paragraph. Letters are individual parts of sentences.

The answer that would make the MOST sense would be SENTENCES

Answer:

301.92 g of CaCl2.

Explanation:

The following data were obtained from the question:

Volume of CaCl2 solution = 3.20 L

Molarity of CaCl2 solution = 0.850 M

Mass of CaCl2 =?

Next, we shall determine the number of mole of CaCl2 in the solution. This can be obtained as illustrated below:

Volume of CaCl2 solution = 3.20 L

Molarity of CaCl2 solution = 0.850 M

Mole of CaCl2 =?

Molarity = mole /Volume

0.850 = mole of CaCl2 /3.20

Cross multiply

Mole of CaCl2 = 0.850 × 3.20

Mole of CaCl2 = 2.72 moles

Finally, we shall determine the mass of the CaCl2 needed to prepare the solution as follow:

Mole of CaCl2 = 2.72 moles

Molar mass of CaCl2 = 40 + (2×35.5)

=40 + 71

= 111 g/mol

Mass of CaCl2 =?

Mole = mass /Molar mass

2.72 = mass of CaCl2 /111

Cross multiply

Mass of CaCl2 = 2.72 × 111

Mass of CaCl2 = 301.92 g

Therefore, 301.92 g of CaCl2 is needed to prepare the solution.

Answer:

it's used to measure intensity of radioactivity in a sample of material