ATI TEAS SCIENCE REVIEW- CHEMISTRY
ATI TEAS SCIENCE – CHEMISTRY
Questions related to chemistry test your knowledge of chemical properties
... [Show More] and
processes. You may be asked questions about states of matter, properties of matter,
phase changes, chemical bonds, chemical solutions, chemical reactions, and acids and
bases. You may be asked to balance chemical equations. Let’s get started in
understanding how chemistry is important on the ATI TEAS.
COVERED AREAS
Understanding States of Matter.
Understanding Changes in States of Matter.
Understanding Properties of Matter
Understanding Chemical Bonds.
Understanding Chemical Solutions.
Understanding Chemical Reactions.
Understanding Acid Base Balance.
Understanding Balancing Chemical Equations.
UNDERSTANDING STATES OF MATTER
Matter is made up of microscopic particles that move different speeds depending on the
energy they are exposed to. We measure this energy as temperature. The molecules can
move either quickly and randomly or hardly at all.
When the energy is high, matter take the form of a gas, in which molecules are moving
about quickly and are far apart. Gases have no fixed form. Molecules are free to move at
random past each other, and they tend to fill any container that holds them. If a gas is
not contained, its molecules will disperse.
Lower temperatures result in a liquid, in which molecules cohere but are fluid.
Coherence means that the molecules remain close together, but they can change
position by sliding over one another. In liquids, molecules move less freely than in a
gaseous state, sliding past one another. They have a fixed volume but will flow freely
unless they fill a portion of a container.
When the temperature is low, matter takes the form of a solid, in which molecules are
packed closely together and retain their positions. Solid matter is rigid, and molecules
retain a uniform spacing. A solid has a defined form, which is brittle. It can be broken
into pieces but tends to stay together.
A somewhat unusual state of matter is plasma, which is like a gas in many of its
properties but carries an electric charge.
The TEAS focus on solids, liquids, and gases.
UNDERSTANDING CHANGES IN STATE OF MATTER
The state of matter depends on temperature and pressure. Higher temperatures cause
molecules to energize and move farther apart. Increasing pressure forces molecules
closer together. Melting is the phase change from solid to liquid and boiling is the phase
change from liquid to gas. There is also a direct change from solid to gas known as
sublimation. The phase change from gas to liquid is condensation and the change from
liquid to solid is freezing. A direct change from gas to solid is deposition.
All types of matter can be described in terms of the physical and chemical properties
each substance has. Physical properties are observable and there is an extensive list of
physical properties that one could observe about a substance. A few examples are
density, the temperatures at which the substance undergoes phase changes,
malleability, conductivity, specific heat capacity, mass, volume, color, and many other
properties. Physical properties are further divided into intensive and extensive
properties. An intensive property does not depend on the size or amount of matter in
the object, while an extensive property does depend on the amount of matter in the
object. For example, mass is extensive because the measurement would change the size
of the sample. Boiling point is intensive because the temperature at which the object
boils is not dependent on its volume.
UNDERSTANDING PROPERTIES OF MATTER- WATER
Water is a polar inorganic compound that is transparent and nearly colorless. H2O is a
covalent compound because oxygen and hydrogen are nonmetals. It has 8 total valence
electrons (6 from oxygen and 1 from each hydrogen). Breaking the bonds requires a lot
of energy, so water has a very high specific heat and heat of vaporization. The molar
mass of water is 18.02 g/mol. It commonly exists as solid, liquid, and gas.
The polarity of water allows it to exhibit both cohesive and adhesive properties.
Cohesiveness allows water to travel through tiny capillaries and creates surface tension
on the surface of a body of water. Adhesiveness allows water to stick to other molecules
and dissolve them, making it known as the “universal solvent.”
Water also has a unique property called osmosis, which is a specific type of diffusion.
Diffusion is a term used to describe the process of a substance moving from an area of
high concentration to an area of low concentration. Osmosis is a type of diffusion in
which water moves passively through a semi-permeable membrane to equalize water
concentration on both sides of the membrane. This is how water moves through cell
walls in the body. [Show Less]