Semester 1 Study Guide Flashcards
Scientific Method
a sequence of events used to test a question
Hypothesis
an explanation of how something happens
Independent Variable
a factor that changes in an experiment
Dependent Variable
a factor that changes as a result of the IV changing
Constant
a factor the remains the same in an experiment
Control Group
an unchanged experiment that is used to compare to other experiments
Bar/column graph is used for ________
comparing data
Line graph is used for _________
data over time
Pie chart is used for ___________
comparing data that is part of a whole
What are the three types of models?
- physical
- mathematical
- conceptual
Identify the benefits and limitations of models.
benefits: can model things that don’t exists; can be kind of like a hypothesis
limitations: don’t act like what it models
Length (and tool)
measures how long something is
ruler
Mass (and tool)
measures how heavy something is
triple beam balance
Volume (and tool)
measures the amount of space something takes up
graduated cylinder
Temperature (and tool)
measures how hot or cold something is
thermometer
Density (and tool)
measures how dense something is (hydrometer)
Matter
anything that is a solid, liquid, or gas and takes up space
Physical Changes
a change of matter from one form to another without a change in chemical properties
Chemical Changes
a change in matter that turns into a different substance
Characteristic Properties
properties most useful in identifying a substance
Reactivity
how two or more substances combine to create one or more new substances
Thermal Conductivity
the rate at which a substance transfers heat
Explain the rule used to decide what is or is not matter.
It has to be a sold, liquid, or gas and it has to be made of atoms
Explain the molecular difference between the three states of matter.
solids - the atoms are very close together and retains its shape
liquids - the atoms are moderately spaced and it takes the form of its container
gas - the atoms are far apart and are moving quickly and will take the shape of its container
Discuss why the mercury in a thermometer rises when heated.
The molecules expand which also expands the actual mercury.
Contrast chemical and physical changes.
chemical - a change that affects the object on a chemical level and sometimes changes the substance
physical - a change that affects the object on a physical level and sometimes changes the object’s appearance
Tell why scientists use characteristic properties to identify substances.
because they are the same for each substance;
ex: a large chunk of iron has the same characteristic properties as a tiny piece of iron
Be able to analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
PRACTICE!
Atom
smallest unit of matter; made up of proton, neutrons, and electrons
Isotopes
an atom with a different amount of neutrons than normal
Atomic Number
the number of protons in an atom
Atomic Mass
the number of both protons and neutrons
Ions
an atom with a different amount of protons or electrons than normal
Ionic Board
M to NM / a bond in which atoms transfer electrons
Covalent Bond
NM to NM / a bond in which atoms share electrons
Reactants
participants in a chemical reaction
Products
created in a chemical reaction
Law of Conservation of Mass
states that mass is neither created nor destroyed
List 5 things that describe an atom.
- composed of protons, neutrons, and electrons
- always moving
- mostly empty space
- very small
- has mass
How can you use the periodic table to identify protons, neutrons, and electrons in an atom?
P = Atomic Number E = Same as P Neutron = Atomic Mass-Atomic Number
Discuss the rules for creating isotopes.
isotopes = uneven amount of neutrons ions = uneven amount of protons and electrons
How can you use the periodic table to determine the number of electron shells and valence electrons for atoms?
groups and periods:
periods = vertical
groups = horizontal
Contrast an ionic bond with a covalent bond. Determine if a molecule/compound is formed by an ionic or covalent bond.
ionic = electrons giving to another atom covalent = electrons being share with another atom ionic = nonmetal ---> metal covalent = nonmetal ---> nonmetal
Describe the relationship between the reactants and the products in a chemical reaction.
You start with reactants. When in contact, the reactants begin reacting to each other. This creates a new substance which is called the product.
Explain the law of conservation of mass as demonstrated in your lab experiences.
The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. For example, if you put two different reactive substances in a bag, weigh them, and get 120 grams. Then you mix them together and weigh them after the reaction, it still weighs 120 grams.
Energy
the ability to do work
Kinetic Energy
energy of motion
Potential Energy
energy an object has due to its position
Mechanical Energy
the sum of PE and KE
Thermal Energy
heat energy due to the random motion of particles
Chemical Energy
energy of a compound that changes as its atoms are rearranged
Electrical Energy
energy of moving electrons
Light Energy
energy produced by the vibrations of electrically charged particles
Nuclear Energy
energy produced from the changes in the nucleus of an atom
Energy Conservation
the act of changing one type of energy to another
Law of Conservation of Energy
a law that states that energy cannot be created or destroyed, but can change from one form to another
Contrast kinetic and potential energy.
kinetic = energy of movement/highest at high speeds potential = energy of an object from its position that could become kinetic/highest at high altitudes
Identify the factors that affect the amount of potential and kinetic energy.
speed = kinetic height = potential friction = reduces both
Explain the relationship between kinetic, potential, and mechanical energy.
NO ANSWER
Describe the energy conversions that take place on a roller coaster, and explain how energy is conserved.
potential —> kinetic (going downhill)
kinetic —> potential (going uphill)
electric —> kinetic (turning wheels to move uphill)
The amount of mechanical energy is always the same, never created or destroyed, so energy is conserved.
Give three examples of one form of energy being converted into another form.
electric —> light (flashlight)
chemical —> kinetic (walking or running)
electric —> sound (radio)
Explain the Law of Conservation of Energy.
States that energy can neither be created nor destroyed.
Example: person going downhill p=100 k=250 350 person near top of hill p=300 k=50 350 It stays the same.
Open Response/Short Answer
Support a claim, using evidence, that when kinetic energy of an object changes, energy is transferred to or from the object.
**PRACTICE WRITING THIS.** Three parts: A - answer the question B - draw a model and label C - total amount of energy
