Chemistry Unit 1 Test—Matter and Energy

Chemical Change

A reaction in which the composition of a substance is changed

Chemical Property

Describes the way a substance will react or not react in a given situation

Chromatography

Separation of liquids based on polarity (using component colors from dye/natural coloring based on their polarity)

Compound

a pure substance composed of two or more elements that are chemically combined in definite proportion

Diatomic

A molecule with two identical elements

What are the diatomic elements?

• Hydrogen (H₂)

• Nitrogen (N₂)

• Fluorine (F₂)

• Oxygen (O₂)

• Iodine (I₂)

• Chlorine (Cl₂)

• Bromine (Br₂)

Distillation

Separating two liquids based on their boiling point (separating two homogeneous liquids by boiling)

Element

A substance that cannot be broken down by chemical means, found on the periodic table

Endothermic

Reaction that absorbs heat; heat enters the reaction

Evaporation

Separation of a dissolved solid from a liquid by heating and evaporating the liquid (often water)

Exothermic

Reaction that releases heat; heat exits the reaction

Filtration

Separation of a liquid and a solid based on particle size

Gas

phase of matter without definite shape or volume

Heterogeneous

a mixture in which the particles are not uniformly mixed, has layers

Homogeneous

a mixture in which particles are uniformly mixed, looks the same throughout

Liquid

phase of matter that has no definite shape, but has definite volume

Matter

anything with mass and volume

Mixture

substance physically combined in variable proportion

Particle Diagram

drawing of atoms and or molecules frozen in time as a solid, liquid, or gas and as an element, compound, or mixture

Physical Change

a change that doesn’t alter the chemical properties of a substance

Physical Property

a trait that describes the way something looks, feels, or smells or how much of a substance there is

Precipitate

the insoluble product of a reaction between two aqueous solutions

Solid

phase of matter with definite shape and volume

Can compounds be broken?

Yes, but only by a chemical reaction

What is the smallest piece of a compound called?

a molecule

What is the most basic form of matter?

An element

How many elements are on the periodic table?

118

How many monatomic elements are there?

111

How many diaatomic elements are there?

7

Why are diatomic elements always bonded to another atom of the same type?

For additional stability

What is the smallest piece of an element?

an atom

What does a heterogenous mixture look like?

Different throughout. May have layers or easily distinguishable parts

What does a homogeneous mixture look like?

The same throughout; it is visually indistinguishable

What are aqueous solutions?

Substances dissolved in water, which are usually homogeneous

What does an (aq) after a chemical formula mean?

It means it’s a homogeneous mixture

What does the chemical formula for a mixture look like?

It will be separated in some way, like with a plus sign

Can a mixture be broken?

Yes, by a physical change

What are examples of chemical properties?

• Will it oxidize in air?

• Is it flammable?

• Does it react with a certain chemical?

• Will it rust or corrode in air?

Is Co a monatomic element, diatomic element, heterogeneous mixture, or homogeneous mixture?

Monatomic element

Is CO a monatomic element, diatomic element, heterogeneous mixture, or homogeneous mixture?

Compound

Is B₂ a monatomic element, diatomic element, heterogeneous mixture, or homogeneous mixture?

Diatomic element

Is the combination of oil and water a monatomic element, diatomic element, heterogeneous mixture, or homogeneous mixture?

Heterogeneous mixture

Is air a monatomic element, diatomic element, heterogeneous mixture, or homogeneous mixture?

Homogeneous mixture

Is salt water a monatomic element, diatomic element, heterogeneous mixture, or homogeneous mixture?

Homogeneous mixture

Is salt and sand a monatomic element, diatomic element, heterogeneous mixture, or homogeneous mixture?

Heterogeneous mixture

Is sulfur being yellow a physical property, chemical property, physical change, or chemical change?

Physical property

Is neon being nonreactive a physical property, chemical property, physical change, or chemical change?

Chemical property

Is copper conducting electricity a physical property, chemical property, physical change, or chemical change?

physical property

Is chlorine reacting with water to form an acid a physical property, chemical property, physical change, or chemical change?

Chemical property

Is baking a cake a physical change or chemical change?

chemical change

Is boiling water a physical change or chemical change?

Physical change

Is burning wood a chemical change or physical change?

Chemical change

Is ripping a piece of paper a chemical change or phsyical change?

Physical change

Is dissolving sugar in water a chemical change or a physical change?

Physical change (can undo it)

What are examples of physical properties?

• Color

• Smell

• Feel

• Taste

What are examples of physical changes?

• Chewing

• Burning

• boiling

• freezing

• Crushing/breaking

• Bending

What are examples of chemical changes?

• color change

• temperature change

• generation of light

• forming of a precipitate (solid)

• new smell

What does each new capital letter represent in a chemical formula?

A new element

What does a subscript number mean in a chemical formula?

the number of atoms for the element abbreviation before it

What does a coefficient (number) mean in a chemical formula?

The number of molecules (how many of that specific combination)

It also multiplies by all the atoms in the formula (to give you the total number of each atom)

What do parentheses do in a chemical formula?

Act as parentheses in math. You multiply to find the total number of atoms

How are particles in solids arranged?

In an organized and predictable pattern

How are particles in liquids arranged?

Particles are somewhat organized with no pattern

How are the particles in gases arranged?

Evenly spread out across the space (container)

What state of matter do these particles represent?

Solid

What state of matter do these particles represent?

Liquid

What state of matter do these particles represent?

Gas

What is the difference between an element and a compound?

An element has particles of all the same type, while a compound has at least two different particles (touching each other)

What is a mixture?

At least two different elements or compounds NOT touching each other

What is the difference between a compound and a mixture?

The elements/particles in a compound touch but they don’t in a mixture

How should you smell chemicals?

Waft, don’t inhale directly

What should you do with your hair when in the lab?

Tie it back

How should you NOT use a pipette?

With your mouth

What should you do when you’re done using chemicals in containers/bottles?

Close/cover them

Where should you NOT measure substances? Where is the correct place to measure them?

Above eye level

leave on desk and measure from there

Are you allowed to eat or drink in the lab?

No

What should you do after you are done with a lab?

Clean up

What should you do with trash and chemicals after a lab?

Dispose of chemicals or trash accordingly (listen to teacher instructions)

What kind of shoes should you wear in the lab?

Close toed shoes

What is the purpose of the fume hood?

To use when dealing with reactions that give off gases or strong reactions. The fume hood keeps the reaction/gas away from you

What is the purpose of the chemical storage cabinet?

To hold supplies and properly store chemicals

What is the fire extinguisher used for?

Putting out fire on inanimate objects

What is the eye wash for?

To wash eyes in the event that chemicals get into your eyes

What is the first-aid kit in the classroom for?

Minor injuries that don’t require going to the nurse

What is the shower in the classroom for?

To wash off if a large portion of your body is exposed to or covered in a chemical

Pure substances

• have a fixed proportion

• cannot break down by physical change

What are two types of pure substances?

elements and compounds

What are two categories of mixtures?

Homogeneous and heterogeneous

What does a diatomic element look like?

What does a monatomic element look like?

What does a compound look like?

What does a mixture look like?

What does a mixture of compounds look like?

What does a mixture of elements and compounds look like?

Precipitation

removing a dissolved substance from a homogeneous mixture by making it react with another substance

Separatory Funnel

separate two heterogeneous liquids by gravity

Evaporation

heating a homogeneous mixture so that the water evaporates leaving behind a salt

Filtration

removing a solid from a liquid. Solid gets caught in the filter and the liquid will pass through (this doesn’t work for homogeneous mixtures)

What kinds of separation can be used for homogeneous mixtures?

Distillation, precipitation, evaporation, chromatography

What kinds of separation can be used for heterogeneous mixtures?

Separatory funnel and filtration