The Particle Model
What does the particle model describe?
It describes how particles are arranged in different states of matter and how they move.
What process changes a solid to a liquid, such as ice melting into water?
Melting
What is diffusion?
The spreading of particles from an area of high concentration to an area of low concentration.
What is an atom?
The smallest unit of matter that retains the properties of an element.
What is a compound?
A substance made of two or more different elements chemically bonded together.
In the particle model, what happens to the particles when a substance is heated?
The particles move faster and spread further apart.
What process occurs when a liquid turns into a gas, like water boiling or drying clothes outside?
Evaporation
How does temperature affect the rate of diffusion?
Diffusion happens faster at higher temperatures because the particles move faster.
What is the name of the center part of an atom?
The nucleus.
What is a mixture?
A mixture is a combination of two or more substances where each retains its own properties and are not chemically bonded.
What state of matter has particles that are packed closely together and vibrate in place?
Solid
What process happens when a gas turns into a liquid, such as when water vapor forms on a cold window?
Condensation
What is density?
Density is how much mass is contained in a given volume.
What are elements made up of?
Atoms of the same type.
What is the difference between an element and a compound?
An element is made of only one type of atom, while a compound is made up of two or more different types of atoms chemically bonded.
What happens to the arrangement of particles when a gas is cooled down?
The particles slow down and move closer together.
What is it called when a solid changes directly into a gas without becoming a liquid first, like dry ice turning into gas?
Sublimation
Why do objects with higher density sink in water?
Objects with higher density have more mass per unit volume, making them heavier than liquid.
How many elements are found on the periodic table.
There are over 100 elements.
Consider the chemical formula Na2SO4. How many atoms and elements are present in this formula?
3 elements and 7 atoms.
What are the 3 main assumptions of the particle theory of matter?
(1) Everything is made of matter, (2) the particles are alway moving, and (3) there are forces of attraction between the particles.
What is deposition?
When a gas turns directly into a solid without becoming a liquid. The opposite of sublimation.
How do you calculate the density of an object?
Density = Mass / Volume.
What is the atomic number of an element, and what does it tell you?
The atomic number is the number of protons in an atom and determines the element’s identity.
Consider the chemical formula C6H12O6 (glucose). How many elements and atoms are present?
There are 3 elements and 24 atoms present.