Chemistry Test Flashcards
Substances can be classified into what two categories?
Elements and compounds
What is a substance that can’t be broken down into simpler substances
An element
What is the smallest particle of an element
An atom
Why does an atom have a fixed composition
Because it contain only one type of element
What is a substance that is made from two or more simpler substances and can be broken down into those simpler substances
A compound
What does a compound always contains
Two or more elements joined at fixed proportion
What is any ability to produce a change in the composition of matter
A chemical property
What can only be observed when the substances in a sample of matter are changing in different substances
Chemical properties
What is a materials ability to burn in the presence of oxygen
Flammability
What is the property that describes how readily a substance combines chemically with another substance
Reactivity
What occurs when a substance reacts and forms one or more new substances
A chemical change
What are the three common types of evidence for a chemical change
Change in color, production of gas, and the formation of a precipitate,
What is any solid that forms a liquid mixture called
A precipitate
What is the difference between a chemical change and a physical change
Chemical change: changes composition of matter
Physical change: composition of matter stays the same
What is a dense positively charged center of the Atom
The nucleus
What are the subatomic particles
Protons, electrons, neutrons
What is a positively charged subatomic particle found in the nucleus of an Atom
Proton
What is a negatively charged subatomic particle found outside nucleus of an atom
Electron
What is a neutral subatomic particle that is found in the nucleus
Neutron
Matter that always has exactly the same composition is classified as a what?
A pure substance