Chemicals & Chemical Reactions - 2b Flashcards
(36 cards)
What is matter?
Matter is defined as anything that has mass and occupies space.
What are the three types of matter?
- Solid - Has a definite shape and a definite volume
- Liquid - Has an indefinite shape and a definite volume
- Gas - Has an indefinite shape and an indefinite volume
What is a physical change?
Changing matter from one form to another form without creating new substances.
What is a chemical change?
Changing matter from one substance into another, creating one or more new substances.
Define a mixture.
A mixture is two or more pure substances where each retains its own chemical identity.
Define a pure substance.
A pure substance is a single kind of matter that cannot be separated into other kinds by physical means.
What is an element?
An element is made of only one type of atom and cannot be broken down into simpler substances.
What is a compound?
A compound is made of more than one type of element in a fixed composition.
What is an atom?
The smallest particle of an element that retains the properties and characteristics of that element.
What are ions?
Ions are formed when an atom gives up or gains an electron.
What is a cation?
A cation is an atom that has lost one or more electrons and has a positive charge.
What is an anion?
An anion is an atom that has gained one or more electrons and has a negative charge.
Define a molecule.
A molecule is two or more atoms joined by a chemical bond that move around as a unit.
What are free radicals?
Electrically charged atoms or groups of atoms with an unpaired electron in its outer shell.
What are antioxidants?
Substances that donate an electron to free radicals to stabilize them without becoming unstable.
What is the octet rule?
Most elements interact to achieve a stable arrangement of 8 electrons in the valence shell.
What are valence electrons?
Electrons found in the outermost electron shell that are more easily gained or lost.
What are the two main types of chemical bonds?
- Ionic: Bonding between oppositely charged ions
- Covalent: Where electrons are shared
What is metabolism?
The total of all the chemical reactions in the body.
What is anabolism?
All the synthesis reactions in the body that usually absorb more energy than they release.
What is catabolism?
All the decomposition reactions in the body that usually release more energy than they absorb.
What does the law of conservation of energy state?
Energy can neither be created nor destroyed; it is converted from one form to another.
What is activation energy?
The collision energy needed to break bonds and begin a reaction.
What is a catalyst?
A substance that lowers the activation energy requirement to speed up a chemical reaction.
