Chapter 2: Basis Of life Flashcards
What is an element?
A pure substance that is made up of ONE atom.
What are bulk elements?
Elements that the body requires in large amounts (95%).
Which elements make up the bulk elements?
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
- Sulfur
- Phosphorus
What are trace elements?
Elements that are required in small amounts; important parts of enzymes.
Ultratrace elements:
Vital in very small amounts; toxic.
What are enzymes?
Proteins that regulate the rate of chemical reactions in living things.
What are isotopes?
Same elements with different amounts of neutrons
Why do isotopes of the same element have the same characteristics even with a different number of neutrons?
They have the same amount of electrons, which determine elements properties.
What is a chemical compound?
A compound made up of two or more elements.
What is the octet rule?
An atom can hold up to 8 electrons in its outermost shell.
What element is an exception to the octet rule?
Hydrogen: hold 2 electrons only
What is an ionic bond?
Bond formed from the transfer of electrons between two or more elements.
Cations & Anions?
Positively charged particles, and negatively charged particles.
What is a covalent bond?
A bond formed between two or more atoms through sharing electrons.
What is Van der Waals Force?
The concept that atoms can form polar regions temporarily, which allows for bonds to form.
Types of chemical reactions:
- Synthesis
- Decomposition
- Exchange Reaction
What is a synthesis reaction?
Two or more molecules come together to form one product.
What is a decomposition reaction?
A reactant breaks down into two or more products.
What is an exchange reaction?
When molecules switch atoms by breaking bonds and forming new ones.
What is dissociation?
When ionically bonded substances are placed in water, they separate by attaching to the positive and negative poles of water molecules.
What are electrolytes?
Substances that release ions when placed in water.
What are acids?
Electrolytes that release H+ ions in water.
What are bases?
Substances that release ions that combine with H ions (OH-)
What are salts?
Bases and acids react and neutralize, forming water and electrolytes called salts.
What are buffers?
Chemicals that resist pH change (weak acids and bases).
