{{asɛmtiNe Ɔkyerɛwfo}} | Nhomakorabea | Nneɛma a ɛma wotumi yɛ ade

Goal:

1. To determine how the strength of attractive forces between the particles affects the temperature at which substances undergo a phase change.

2. To be able to explain how attractive forces between particles are related to chemical potential energy.

The PHET simulation is embedded in the formative. If you can not access it then use this link to open the PHET simulation in another window.

https://phet.colorado.edu/en/simulations/states-of-matter

Note: This is an investigation and your answers will vary. Since. I can't put in the correct answers ahead of time, most of yours answers will be marked wrong, until I grade them.

1

Before you start, use the drawing tools to draw a cartoon that compares how particles are arranged in a solid, liquid or gas. Not sure what to draw? Check out this video to review solids, liquids and gasses.

Investigation #1 Melting Point and Boiling Point.

o Click on the States icon in the home menu

o Play with the simulation to estimate the melting point and the boiling point of each substance.

o The melting point is where is the substance has approximately half the atoms as solid and half as liquid.

o The boiling point is where is the substance has approximately half the atoms as liquid and half as gas.

To heat the particles move the slider to heat. To cool the particles move the slider to cool.

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Note: The Kelvin temperature scale starts at 0. The symbol for the temperature unit is K. At 0 K, there is no movement of particles. The Kelvin scale is used when temperatures are very very low. It has an advantage over Celcius or Fahrenheit in that all temperatures are positive. 293K is room temperature.

1

Click on Neon and slowly heat the particles. Describe

3

Click on Neon and slowly heat the particles. Observe how the motion of the particles changes and then fill in these sentences.

When the temperature , the speed of the particles . Since kinetic energy is related to speed of the particles , the kinetic energy of the particles

0

My estimated melting point of Neon is between K and K. The estimated boiling point is between and .

0

Repeat your experiment with Argon and fill in the sentences below.

My estimated melting point of Argon is between K and K. The estimated boiling point is between and .

0

Repeat your experiment with Oxygen and fill in the following sentences.

My estimated melting point for oxygen is between K and K. The estimated boiling point is between and .

0

Repeat your experiment with water and fill in the sentences below.

My estimated melting point of water is between K and K. The estimated boiling point is between and .

1

Organize the substances so the element with the lowest melting point is on the top and the highest melting point is on the bottom.

Neon
Oxygen
Water
Argon

Investigation #2: Strength of Attraction

Question: How does the strength of attraction between the particles affect the melting point and boiling point of a substance?

Hit the Home Icon
Click on the phase changes icon.
Click on the green plus sign next to interaction potential to open the interaction potential box. Your screen should look like set.

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Use the simulation to answer the questions below.

3

The interaction strength slider changes the strength of the attractive forces between the particles. The length of arrow marked with the ε is proportional to the potential energy related to the attractive force between the particles. Play with the slider and write a sentence to describe the relationship between the potential energy and the strength of the attractive force between the particles.

0

Set the slider on the interaction strength to strong. All the way over to left. Then use the simulation to fill in the sentence below.

When the attraction is strongest between the particles, the estimated melting point is between K and K. The estimated boiling point is between and .

0

Set the slider on the interaction strength to weak. All the way over to left. Then use the simulation to fill in the sentence below.

When the attraction is weakest between the particles, the estimated melting point is between K and K. The estimated boiling point is between and .

8

Consider your results and then fill in these sentences to write your interpretation.

attractive forces. Substances with attractive forces between the have melting points. More has to be added to the to overcome the attractive forces and allow the particles to move more . The Law of Conservation of Energy says the energy added to the system is equal to the change in the energy of the system.

Mmuae Afoforo a Wobɛpaw:

particles

system

potential

heat

higher

freely

Hit the Home Icon
Click on the interaction icon
Choose adjustable attraction.
Click on the green + and open the Forces panel.
Click on Attractive/Repulsive Force button. As you move the purple atoms, you should see orange and pink arrows appear on purple atoms. A force is a push of a pull. The direction and color of the arrows shows whether the atoms are attracting or repelling each other.
Set the slider on the attractive forces to strong.

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Use your mouse to drag the pink particle on the curve to each position (A,B,C,D) by moving the right atom. Push play on the simulation.

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Use your conclusions to fill in the sentences below.

1

When the cyan dot is at position A, the attractive force is than the repulsive force.

1

Describe how the atoms move relative to each other when you push play when the cyan dot is at position A.

1

When the cyan dot is at position B, the attractive force is than the repulsive force.

1

Describe how the atoms move relative to each other when you push play when the cyan dot is at position B.

1

When the cyan dot is at position C, the attractive force is than the repulsive force.

1

Describe how the atoms move relative to each other when you push play when the cyan dot is at position C.

1

When the cyan dot is at position D, the attractive force is than the repulsive force.

1

Describe how the atoms move relative to each other when you push play when the cyan dot is at position D.

Magnets are another examples of particles with attraction and repulsion. Get a set of magnets from the supply table and set up them up to explore how the attraction and repulsion depends on the distance between the magnets.

1

If you have 3 magnets attracting 1 magnet, at what distance will they slide towards each other?

1

If you have 5 magnets attracting 1 magnet, at what distance will they slide towards each other?

3

Compare the behavior of the magnets and the atoms in the simulations. What are three similarities between the them.

3

Compare the behavior of the magnets and the atoms in the simulations. What are three differences between the them.

1

How could you use the magnets to demonstrate that there is stored potential energy when the magnets are attracted to each other?

9

The potential energy of the atoms is highest at point and lowest at point . The atoms tend to move towards the point with the potential energy. This is like our experience of gravity. The potential energy due to gravity is highest when we are from the center of the earth and lowest when we are to the center of the earth. Without something to push against gravity like a floor, we tend to fall towards the point with the lowest energy. The magnets also move towards the potential energy. The potential energy is high when the magnets are apart and lower when the magnets are together.

Mmuae Afoforo a Wobɛpaw:

D

B

closer

highest

A

lowest

C

farther

potential

40

One definition of potential energy is that it is the energy that depends on the relative positions or distance between the particles. Chemical potential energy is the potential energy associated with a certain substance at a certain temperature. Use the evidence that you have accumulated to write a short CER supporting the claim, that chemical potential energy depends on the distance between the atoms in a substance. You should have at least three pieces of evidence and three reasoning sentences that explain how the evidence supports the claim.

Lesson 2.4 Attractive Forces Investigation

Lesson 2.4 Attractive Forces Investigation

Before you start, use the drawing tools to draw a cartoon that compares how particles are arranged in a solid, liquid or gas. Not sure what to draw? Check out this video to review solids, liquids and gasses.

Click on Neon and slowly heat the particles. Describe

Organize the substances so the element with the lowest melting point is on the top and the highest melting point is on the bottom.

Describe how the atoms move relative to each other when you push play when the cyan dot is at position A.

Describe how the atoms move relative to each other when you push play when the cyan dot is at position B.

Describe how the atoms move relative to each other when you push play when the cyan dot is at position C.

Describe how the atoms move relative to each other when you push play when the cyan dot is at position D.

If you have 3 magnets attracting 1 magnet, at what distance will they slide towards each other?

If you have 5 magnets attracting 1 magnet, at what distance will they slide towards each other?

Compare the behavior of the magnets and the atoms in the simulations. What are three similarities between the them.

Compare the behavior of the magnets and the atoms in the simulations. What are three differences between the them.

How could you use the magnets to demonstrate that there is stored potential energy when the magnets are attracted to each other?

Before you start, use the drawing tools to draw a cartoon that compares how particles are arranged in a solid, liquid or gas. Not sure what to draw? Check out this video to review solids, liquids and gasses.

Click on Neon and slowly heat the particles. Describe

Organize the substances so the element with the lowest melting point is on the top and the highest melting point is on the bottom.

Describe how the atoms move relative to each other when you push play when the cyan dot is at position A.

Describe how the atoms move relative to each other when you push play when the cyan dot is at position B.

Describe how the atoms move relative to each other when you push play when the cyan dot is at position C.

Describe how the atoms move relative to each other when you push play when the cyan dot is at position D.

If you have 3 magnets attracting 1 magnet, at what distance will they slide towards each other?

If you have 5 magnets attracting 1 magnet, at what distance will they slide towards each other?

Compare the behavior of the magnets and the atoms in the simulations. What are three similarities between the them.

Compare the behavior of the magnets and the atoms in the simulations. What are three differences between the them.

How could you use the magnets to demonstrate that there is stored potential energy when the magnets are attracted to each other?