8th Grade Science Small Particle Theory

What happens to the thermal energy and cohesion attraction between particles in a substance during melting, boiling, freezing, condensing, and sublimating?

melting: solid to liquid boiling: liquid to gas freezing: liquid to solid condensing: gas to liquid sublimating: solid to gas melting: thermal energy increases, cohesion attraction weakens boiling: thermal energy increases, cohesion attraction weakens freezing: thermal energy decreases, cohesion attraction gets stronger condensing: thermal energy decreases, cohesion attraction gets stronger sublimating: thermal energy increases, cohesion attraction weakens

What is happening on a thermal energy graph when the temperature of a substance is undergoing a phase change? Why?

look at graph

What is Charles' Law? How could you use this to predict the volume or temperature of a gas?

- Charles' Law - A principle that describe the relationship between the temperature and volume of a gas at constant pressure. (When the temperature of a gas at constant pressure is increased, its volume increases. When the temperature of the gas at constant pressure is decreased its volume decreases.)(directly proportional) - You could use this to predict the volume or temperature of a gas because if the gas had a constant pressure, you could estimate if the temperature goes up, the volume goes up, and if the temperature goes down, the volume will go down. This is because it is directly proportional. -temperature and volume are directly proportional -as temp increases, volume increases -as temp decreases, volume decreases

What is Boyle's Law? How could you use this to predict the pressure or volume of a gas?

A principle that describes the relationship between the pressure and volume of a gas at constant temperature. (When the pressure of a gas at constant temperature is increased, the volume of the gas decreases. When the pressure is decreased, the volume increases.) -volume and pressure are inversely proportional -as volume increases, pressure decreases -as pressure increases, volume decreases

How are the temperature and pressure of a gas related?

Gay-Lussac's Law is one part of the ideal gas law and so explains how gases change when volume is held constant. As the temperature increases, the molecules in the gas move faster, impacting the gas's container more frequently and exerting a greater force. This increases the pressure. (like a soda can)

How does temperature affect the average motion energy of the particles? What happens to the particles when a substance is heated? Cooled?

Temperature affects the average motion energy of the particles, because when the temperature increases, the cohesion attraction weakens, and the particles gain more energy, causing them to move faster and spread farther apart. When the temperature decreases, the cohesion attraction strengthens, and the particles lose energy, causing them to slow down and come closer together. the higher the temperature, the faster the average motion energy of the particles when a substance is heated, the particles move faster and faster. a solid turns into a liquid because more energy is being transferred to the particles from the temperature so the particles inside of the solid move fast enough so that they break out of their fixed positions when a substance is cooled, the particles inside of the substance slow down because they are loosing energy

How do gases, liquids, and solids move? Are they the same? Different?

The gas particles move fastest and they rarely bump into each other, the liquid particles move slower, frequently bumping into each other. Solids just vibrate in place, not moving out of the same place. solids: the particles vibrate in place liquids: the particles move around in all directions gas: the particles are far apart and moving faster than particles in a liquid

How are the volume and temperature of a gas related?

They are directly proportional. At a constant pressure, if the temperature goes up, the volume will go up, if the temperature goes down, the volume will go down.

How are the pressure and volume of a gas related?

They are related because they are indirectly proportional. If the temperature is constant in a gas, if the pressure of the gas goes up, the volume will go down, if the pressure goes down down, the volume will go up. (Boyle's Law)

What is the difference between evaporation and vaporization?

Vaporization - The change of state from a liquid to a gas Evaporation - The process by which molecules at the surface of a liquid absorb enough energy to change to a gas. (Vaporization that only takes place on the surface of a liquid) evaporation: evaporation takes place only on the surface of a liquid. this is where a liquid turns into vapor(gas) Evaporation only occurs on the surface. Vaporization is what occurs in the liquid, evaporation occurs only on the surface

What is cohesion attraction?

Wikipedia: "the action or property of like molecules sticking together, being mutually attractive." The attraction of the molecules being drawn towards each other. the particles of a substance are continuously attracted to each other, even when they are not touching

What is the small particle theory? Why did scientists create it?

all matter consists of many, very small particles which are constantly moving or in a continual state of motion. The degree to which the particles move is determined by the amount of energy they have and their relationship to other particles. scientists created it because it helped us understand the motion of the 3 states of matter better

How does the cohesion strength between particles related to its melting temp?

at the melting point (solid to liquid), the particles inside the solid vibrate so fast that they break out of their fixed positions. the cohesion attraction then weakens

What is diffusion? How can you compare the rate of diffusion for solids, liquids, and gases? Why is it different?

diffusion occurs when particles spread. They move from a region where they are in high concentration to a region where they are in low concentration. Diffusion happens when the particles are free to move. solids: slow rate of diffusion liquids: rate of diffusion is higher than a solids rate of diffusion gas: very high rate of diffusion the diffusion rate for solids, liquids, and gases are different because it is harder for particles to spread through a solid because the particles inside a solid are so close together. It is really easy for particles to spread through a gas because the particles in a gas are much more spread out. one substance moving through another

Can you provide an example to support each of these properties?

give me an example of an object that has definite shape and volume: ruler solid: ruler, brick, gas: hydrogen, carbon dioxide liquid: water, acid

How does a cohesion interaction change with a phase change?

solid to liquid: gets weaker liquid to gas: gets weaker solid to gas: gets weaker very quickly

Can you discuss, and provide evidence for, the cohesion interaction between water molecules? (gas, liquid, and solid)

solid: a solid has a high cohesion attraction because it is the hardest substance to pull/break apart liquid: a solid has a smaller cohesion attraction compared to a solid but there still is one because it is kind of hard to move through a liquid and/or break/pull it apart gas: a gas has a very small cohesion attraction because you can easily put your hand through gas or break/pull apart gas

What are some similarities between each? Differences?

solids and liquids have a definite volume, gases don't have a definite volume gas and liquid particles can bump into one another, particles in a solid never touch

Can you summarize the shape, volume, and density of solids, liquids, and gases?

solids: definite shape, definite volume, the particles are in a tightly packed fixed position, particles never touch one another liquids: no definite shape, definite volume, the particles are close together but move around freely, particles bump into one another often gas: no definite shape, no definite volume, the particles move around freely and are quite far away from one another, particles rarely bump into one another

Is the strength of a cohesion interaction the same for all particles? Why or why not?

solids: there is a very strong cohesion attraction liquid: there is a strong cohesion attraction but is slightly weaker compared to a solid gas: there is a very weak cohesion attraction

How is the amount of empty space between particles different for solids, liquids, and gases?

solids: there is little to no empty space liquids: there is more empty space in a liquid compared to a solid but there is still not a lot gas: there is a lot of empty space

What happens when particles bump into each other? Do they change direction? Speed?

when particles bump into each other, they bounce apart in opposite directions. they never change speed. solid particles have no collision. liquid particles have many collisions. gas particles have very few collisions