Name the 4 states of matter
solid, liquid, gas, plasma
What are these examples of?
melting/boiling point
temperature
color
state
texture
odor
physical properties
What is a pure substance?
matter that contains only one type of atom
What are these examples of?
reactivity
acidity/basicity
flammability
chemical properties
True/false:
New substances are created during a physical change
false
True/false:
Matter can change states during physical changes
true
Is salt dissolving a physical or chemical change?
physical change
True/false:
Ruse forming is a physical change
false
Do chemical changes create (at least one) new substance(s)?
yes
Exothermic OR endothermic:
more total energy is required to break bonds in the substance than the total energy is released when new bonds are formed
endothermic
Exothermic OR endothermic:
less energy is required to break bonds than the amount of energy that is released when new bonds are created
exothermic
Is cooking an example of a chemical change or a physical change?
chemical
Define “elements”
they are a pure substance containing only one type of atom
Define “compounds”
pure substances that contain at least two types of atoms that are chemically combined by fixed ratios
Define “mixture”
when two or more different substances that are not chemically combined
Define “solution”
when one substance (the solute) dissolves evenly into another substance (the solvent)
Solvents are usually a ___
liquid
what can compounds be classified as?
ionic or covalent
What is it called when a metallic element reacts with a nonmetallic element?
ionic bonds are formed
What is it called when two nonmetals react?
covalent molecular bonds are formed
How do atoms become chemically stable?
Atoms lose, gain, or share electrons to have a completely filled outer shell (valence level)
What do chemical formulas show?
The number of atoms that each element has that form compounds
What do chemical equations show?
The changes that happen during a chemical reaction
What does the law of conservation of matter say?
That even if a substance goes through chemical or physical changes, the total mass remains the same