8th Grade Science Chapter 2 and 3 Matter Test Review
a single kind of matter that is pure, meaning it always has a specific make-up - or composition - and a specific set of properties.
a pure substance that cannot be broken down into any other substance by physical or chemical means. Elements are the simplest substances.
What are the simplest substances?
The basic particle from which all elements are made. Different elements have different properties because they have different atoms.
pure substance made of two or more elements chemically combined in a set ratio.
How do you represent a compound?
using a chemical formula which shows the elements and their ratio of atoms.
when atoms combine they use the force of attraction between two atoms.
made of two or more substances, elements or compounds or both, that are together in the same place but are not chemically combined.
How do mixtures differ from compounds?
1. Each substance keeps its individual properties.
2. Parts of a mixture are not combined in a set ratio.
measurement of the amount of matter in an object.
measure of the force of gravity on an object.
Does mass or weight change with the location of the object?
Mass does not, weight does.
The amount of space that matter occupies.
relates the mass of a material in a given volume.
a change that occurs when energy is absorbed by a substance.
Formula for Volume
V= Length x Width x Height
SI unit for Volume
Formula for Density
D = Mass/Volume
a change that occurs when energy is released by a substance.
the ability to do work or cause change
a substance that flows
a property of liquid to resist flowing
the force of a gas's outward push divided by the area of the walls of the container
What is the formula for pressure?
PRESSURE = FORCE/AREA
the result of the inward pull among the molecules of a liquid that brings the molecules on the surface closer together. It is a property of liquids. As a result of this property, some liquids can act as a sort of skin.
What is a physical property of matter? Give two examples.
A characteristic of a pure substance that can be observed without changing it into another substance. Examples: freezing, melting, evaporation points, harness, texture, color, state, dissolvable, luster, malleability, flexibility,
What is a chemical property? give two examples.
characteristic of a pure substance that describes its ability to change into different substances. To observe these properties you must try to turn it into another substance. Examples: flammability, rust, oxidation, reactivity,
What are two types of mixtures?
Define Heterogeneous Mixture
You can see the different parts of the mixture.
so evenly mixed that you can not see the different parts. A SOLUTION is an example.
What is the best example of a HOMOGENOUS MIXTURE?
A solution; Air, Salt Water, Brass
What is an example of a HETEROGENOUS MIXTURE?
Soil, salad, legos
Groups of two or more atoms held together by chemical bonds.
3 Examples of Molecules
Water, Oxygen, Carbon Dioxide, Salt
What is Chemistry?
Study of the properties of matter and how matter changes.
List and describe the 5 disciplines of chemistry.
Organic Chemistry - the study of carbon and its compounds; the study of the chemistry of life.
Inorganic Chemistry - the study of compounds not-covered by organic chemistry; the study of inorganic compounds or compounds which do not contain a C-H bond. Many inorganic compounds are those which contain metals.
Analytical Chemistry - the study of the chemistry of matter and the development of tools used to measure properties of matter.
Physical Chemistry - the branch of chemistry that applies physics to the study of chemistry. Commonly this includes the applications of thermodynamics and quantum mechanics to chemistry.
Biohemistry - the study of chemical processes that occur inside of living organisms.
What is the difference between mass and weight?
Mass does not change and is the amount of matter in an object. Weight changes with position in a gravity field and the gravity field and is just the measure of gravity affecting an object.
What is the formula for density?
DENSITY = MASS/VOLUME
What is the SI unit for Density?
g/cm3 (grams per centimeters cubed)
What is a physical change in matter? Give two examples.
Any change that alters the form or appearance of matter but does not make any substance in the matter into a different substance. EXAMPLE:
1. Change in state (solid, liquid, gas)
2. Change in shape
What is a chemical change in matter? Give two examples.
a change in matter that produces one or more new substances. EXAMPLES:
What is the difference between ENDOTHERMIC and EXOGTHERMIC?
ENDOTHERMIC: Absorbs energy to support a reaction.
EXOTHERMIC: radiates energy as a product of a reaction.
What are the three states of matter?
Create a table describing the shape and volume for each state of matter.
STATE SHAPE VOLUME EXAMPLE
Solid Definite Definite Diamond
Liquid Not Definite Definite Water
Gas Not Definite Not Definite Air
Sketch Picture of the particles of gas, liquid, and solid.
List and define the six phase changes. tell whether they are endothermic or exothermic.
1. Melting: Change from a solid to a liquid. ENDOTHERMIC.
2. Freezing: Change from a liquid to a solid. EXOTHERMIC.
3. Evaporation: When a liquid turns into a gas only at the surface. ENDOTHERMIC.
4. Boiling: Liquid changes to a gas below its surface as well as at the surface. ENDOTHERMIC
5. Condensation: occurs when particles in gas loses enough energy to form a liquid. EXOTHERMIC
6. Sublimation: Particles of a solid go strait to gas. ENDOTHERMIC
Exothermic or Endothermic - Melting?
Exothermic or Endothermic - Freezing?
Exothermic or Endothermic - Evaporation?
Exothermic or Endothermic - Boiling?
Exothermic or Endothermic - Condensation?
Exothermic or Endothermic - Sublimation?
What are two types of vaporization?
Changing from a liquid to a gas at the surface.
Changing from a liquid to a gas at the surface and below the surface at the same time.
How are evaporation and boiling different?
Water does not change to gas below the surface during evaporation. Substances have a boiling point. they don't have evaporation points.
Sketch a heating curve of matter.
Sketch the cooling curve of matter
What is Boyles Law?
At a constant temperature:
1.To increase pressure you must reduce the volume.
2. To decrease pressure you must increase the volume.
Is Boyles law direct or an inverse relationship?
What stays constant in BOYLES LAW?
What are the two variables in BOYLES LAW?
Pressure and Volume
What is Charles Law?
At constant pressure:
1. To increase temperature you must decrease volume.
2. To decrease temperature you must increase volume.
What stays constant in Charles law?
What are the two variables in Charles Law?
Temperature and Volume
Draw a graph of Boyles Law. Label the X and Y Axis.
Draw a graph of Charles Law. Label the X and Y Axis.