Chemistry: Atoms

The strength of forces depends on which three things?

The strength of forces depends on which three things?

1. Material

2. Temperature

3. Pressure

Describe the arrangement of particles in solid?

The particles in a solid have a strong force of attraction between them, they have regular lattice arrangement. They do not move around but vibrate in their fixed positions though they expand slightly when heated. They have both definite shape and volume.

Describe the arrangement of particles in a liquid.

The particles in a liquid have weak forces of attraction between them. The particles in a liquid are close together but not in a fixed position, allowing them to slide past one another. This gives liquids a definite volume but no definite shape, taking the shape of their container. As the liquid gets hotter the particles gain more energy and expand slightly.

Describe the arrangement of particles in a gas.

The particles in a gas have very weak forces of attraction between them and are far apart, moving freely and rapidly in all directions. The particles in gasses travel in straight lines. This results in no definite shape or volume, as gases expand to fill their container. As the temperature increases, the particles move faster and spread further apart. Gasses will either expand when heated, or the pressure will increase.

Describe what happens to the particles when a substance turns from solid to liquid to gas.

When a substance turns from solid to liquid to gas, the particles gain energy and vibrate more which weakens the forces that hold the forces together, the solid expands. The particles move from a fixed position to a more fluid state, eventually moving freely. This process is called melting. Followed by evaporation, as the liquid is heated, it expands and the particles gain more energy and vibrate which break the bonds between the particles. Soon the liquid turns into a gas.

What is process called when a solid turns directly into a gas?

Sublimation

What is diffusion?

Diffusion is the process by which particles spread from an area of higher concentration to an area of lower concentration, resulting in a uniform distribution.

Why does diffusion occur?

Diffusion occurs due to the random movement of particles, driven by their kinetic energy, which leads them to move from areas of high concentration to areas of low concentration until evenly distributed.

What experiment can we use to demonstrate diffusion?

We can use potassium manganate(VII) and water to demonstrate diffusion. When potassium manganate(VII) is added to water, it gradually spreads out, illustrating how particles move from an area of higher concentration to lower concentration. In the end, the potassium manganate(VII) evenly spreads out.

When potassium manganate(VII) is added to water, it forms a purple liquid. When we add water to this solution, the solution dilutes.
What is dilution? And what would be the color of the solution after we add more water?

Dilution is the process of reducing the concentration of a solute in a solution by adding more solvent. After adding more water, the solution will become lighter in color, eventually appearing light purple.

What other experiment can we use to demonstrate diffusion? (Hint: Hydrogen Chloride)

We can use the experiment of placing hydrochloric acid [HCI] and aqueous ammonia [NH₃] solution in a closed tube. When the two gases meet, they react to form a ring of white ammonium chloride smoke, illustrating diffusion as the gases move toward each other.

During the ammonia and hydrogen chloride experiment, why does the ring of ammonium chloride form closer to the hydrochloric acid?

The ring of ammonium chloride forms closer to the hydrochloric acid because ammonia particles are smaller and lighter so they diffuse through the air more quickly.

Describe the properties of bromine gas. How can we use bromine gas to demonstrate diffusion?

Bromine gas is brown in color and it is very strong smelling. We can use bromine gas to demonstrate diffusion in the following way:

1) We will fill a gas jar full of bromine gas and another gas jar filled with air, separating them with a glass plate.
2) When the glass plate is removed, we can observe that the bromine gas slowly diffuses through the air due to the random motion of particles.
In the end, the bromine gas fills throughout both the jars, turning into a pale brown due to the bromine particles spreading further apart.

Explain what mixture and what it is made out of?

A mixture is made up of a solute and solvent. A solute is the solid that’s mixed into the solvent, which is the liquid.

What is the difference between a solution and a mixture?

Solution:
A solution is made when the solute and the solvent are mixed, and their bonds break and the molecules of the solute mix with the molecules of the solvent. This is known as dissolving. An example of this is saltwater or air.
Mixture:
A mixture is made when a solute and solvent are mixed together but you can physically separate them by using e.g. a strainer or filter paper. An example of this is sand water.

What is a saturated solution?

A saturated solution is a solution where the maximum amount of solute has been dissolved, so no more solute will dissolve in the solution.