C2: Biological Molecules Part I Flashcards
When carbon dioxide dissolves in water, what does it form after reaction?
an acid
What is a compound?
a substance that has two or more elements in a fixed ratio
What are the 4 most common elements in our body? (In order)
oxygen, carbon, hydrogen, nitrogen
What are trace elements common additives to?
food and water
Define an atom.
the smallest unit of matter that still has the properties of an element
What is an atom’s atomic number?
the unique number of protons
How do you calculate an atom’s atomic mass?
mass of protons + mass of neutrons
What is an atom’s mass number?
sum of the number of its protons and neutrons
Differentiate mass number and atomic mass.
Mass number is the number of protons and neutrons on atom has. Atomic mass is the combined mass of the protons and neutrons. They are approximately equal to each other.
What are the outermost electron shells called?
valence shells
What is a valence number?
the number of electrons in the outer shell
What are isotopes?
different forms of an element; same number of protons but different number of neutrons
What is an ionic bond?
a chemical bond formed by the transferring of electrons between atoms (oppositely charged ions then attract)
What is a covalent bond?
a chemical bond formed when two atoms share electrons
What is the difference between a non-polar covalent bond and a polar covalent bond?
In non-polar covalent bonds, electrons are shared equally. In polar covalent bonds, electrons are pulled closer to a certain atom.
What is electronegativity?
measure of an atom’s ability to attract electrons towards itself in a chemical bond
What is an ion?
an atom or molecule with an electric charge due to the gain or loss of electrons
What are hydrogen bonds?
weak bonds that form between polar molecules
What are partial charges?
charges that result from uneven electron distribution in polar covalent bonds
Define reactants and products.
Reactants are the starting materials in a chemical reaction and products are the resulting materials.
What is cohesion and adhesion?
Cohesion is the attraction between same molecules. Adhesion is the attraction between different molecules.
What is surface tension?
a measure of how difficult it is to break the surface of a liquid
Why is ice less dense than liquid water?
The arrangement of molecules in ice causes the molecules to be spaced far apart
What are solutions, solvents, and solutes?
Solutions are mixtures composed of two or more substances. Solvents are substances that allow other substances to be dissolved in. Solutes are the substances that get dissolved.
Why are non-polar molecules insoluble in water?
The water molecules are attracted to each other instead of the non-polar molecules.
What is the specific heat of a substance?
the amount of heat required to raise the substance’s temperature by a given amount
What is the specific heat of water?
1 calorie
What is thermal energy?
energy associated with the random movement of atoms and molecules
Describe the process of evaporative cooling.
When a substance evaporates, the surface of the remaining liquid cools down.
What is the latent heat of vaporization?
the measure of the heat energy needed to turn a liquid into gas
What is a reagent?
substance that is used to measure or produce other substances
What is the pH scale?
scale that measures acidity or basicity of a solution (a higher concentration of H+ ions results in higher acidity)
Define acids and bases.
Acids are substances that release H+ ions when dissolved in water. Bases are substances that accept H+ ions.
What minimizes changes in pH?
a buffer
