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3 years ago

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom?

Chemistry

1 answer:

ser-zykov [4K]3 years ago

7 0

Answer:

Option D

Explanation:

Rutherford deduced that the atomic nucleus was positively charged because the alpha particles that he fired at the metal foils were positively charged, and like charges repel. Alpha particles consist of two protons and two neutrons, so they are positively charged. In Rutherford's experiments most of the alpha particles passed straight through the foil without being deflected. However, occasionally the alpha particles were deflected in their paths, and rarely the alpha particles were deflected backward at a 180 degree angle.

Since like charges repel, Rutherford concluded that the cause of the deflections of the positively charged alpha particles had to be something within the atom that was also positively charged. Rutherford concluded from his metal foil experiments that most of an atom is empty space with a tiny, dense, positively charged nucleus at the center that contains most of the mass of the atom.

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Anh measured the temperature of a pond near his house. Before he left for school, the water in the pond was 18 degrees celsius.

Hitman42 [59]

As the temperature increases, B) the molecules started moving faster.

Explanation:

The temperature of a substance is a measure of the average kinetic energy of the particles in a substance. In particular, it can be found that the temperature is directly proportional to the average kinetic energy of the particles:

$T\propto KE$

The kinetic energy of a particle is given by

$KE=\frac{1}{2}mv^2$

where

m is the mass of the particle

v is its speed

This means that the higher the temperature of a substance, the greater the speed of the particles in the substance.

Therefore, if we apply this concept to this problem, we infer that as the temperature of the water in the pond gets higher, the speed of the molecules inside the water increases, which means that the molecules are moving faster.

Therefore, the correct answer is

B) the molecules started moving faster.

Learn more about temperature:

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#LearnwithBrainly

3 0

4 years ago

A chemist measures the enthalpy change ?H during the following reaction: Fe (s) + 2HCl (g) ? FeCl2 (s) + H2 (g) =?H?157.kJ Use t

erik [133]

Correct Question:

A chemist measures the enthalpy change ΔH during the following reaction: Fe(s) + 2HCl(g)-->FeCl2(s) + H2 ΔH=-157.0 kJ. Use this information to complete the table below. Round each of your answers to the nearest kJ/mol

Answer:

-314 kJ

+628 kJ

+157 kJ

Explanation:

The enthalpy change of a reaction measures the amount of heat that is lost or gained by it. If ΔH >0 the heat is gained, and the reaction is called endothermic, if ΔH<0, the heat is lost, and the reaction is called exothermic.

If the reaction is inverted, the value of ΔH is inverted too (the opposite endothermic reaction is exothermic), and if the reaction is multiplied by a constant, ΔH will be multiplied by it too.

1) 2Fe(s) + 4HCl --> 2FeCl2(s) + 2H2(g)

This reaction is the product of the given reaction by 2, so

ΔH = 2*(-157) = -314 kJ

2) 4FeCl2(s) + 4H2(g) --> 4Fe(s) + 8HCl(g)

This reaction is the inverted reaction given multiplied by 4, so

ΔH = 4*(157) = +628 kJ

3) FeCl2(s) + H2(g) --> Fe(s) + 2HCl

This reaction is the inverted reaction given, so

ΔH = +157 kJ

4 0

3 years ago

Which element would you expect to have properties similar to Chlorine (Cl)

jeyben [28]

Answer:

Iodine

Explanation:

It's in the same group as chlorine.

5 0

4 years ago

NEED HELP ASAP PLEASE

frutty [35]

C. NO2 is covalent. Hope this helps!

6 0

3 years ago

Read 2 more answers

Imagine the movement of a single gas molecule inside a container. Explain the particles motions in terms of kinetic- molecular t

Nikitich [7]

Answer:

we know that gas molecules move fast by hitting the container and they never meet,so if we have one single gas molecule then it will move slower . This is because it is alone in an empty container so until it hits the container to change it's movements it will make the process slower.

Read the explanation below to have a better idea based on the kinetic molecular theory.

Explanation:

Hello in this question we have a container and in it is a single gas molecule. So there is our gas molecule and in fact right there that violates the kinetic molecular theory. Because the kinetic molecular theory thinks of these particles as being dimension less points. Because there is so much space between particles. The particles themselves have such an insignificant volume as they can be thought of as dimension lys points. Okay. But anyway this particle is in rapid motion and this motion is essentially random. So it's moving and it will eventually hit the wall of its container. It's moving rapidly so it's going to hit it pretty quickly and when it hits the wall of that container Yeah, it is going to bounce off when it does that. It's a totally elastic collision. So that means there will be no energy transfer, no energy loss, no energy gained. It will just serve to change the direction of the particle. So when it hits the wall it's going to bounce back off the wall and continue in a straight line until it hits another wall and then it will bounce off that wall and it will continue moving in this motion in this motion its speed is related to the amount of energy it has and therefore its temperature. So if we add heat, it will move faster. If we remove heat or cool it down, it will move slower. So when we remove heat, it will move slower. The kinetic molecular theory says it will be constantly moving As long as it is above absolute zero. It's only at absolute zero or 0 Kelvin, where would stop moving. Okay, so all these things describe its motion. It's in rapid random motion in a straight line until it hits the wall of its container. Then it will rebound without a transfer of any energy. It will be totally elastic collision. If we were to heat it up, it would move faster. If we were to cool it down, it would move more slowly, we would have to cool it all the way down to absolute zero before it would stop moving. Right, so all of these things describe its motion. In terms of that kinetic molecular theory,

5 0

2 years ago