Unit 1.1 - 1.2

Recommended use: Test mode, multiple choice only or flashcards

What states does matter exist in?

solid, liquid, gas

What are the six main elements found in all living things?

carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur

Which element is the most abundant in living things?

carbon

What element makes up the majority of earth’s atmospheres?

nitrogen

What three components make up an atom?

protons, neutrons, electrons

What are trace elements?

elements that are required by an organism but only in minute quantities (ex. iron)

What are isotopes?

atoms of the same element but have different number of neutrons

What is half-life of isotopes?

the amount of time it takes for half a sample of radioactive isotopes to decay into more stable isotopes

A compound is made of how many elements bonded together?

two or more

What are the two types of chemical bonds?`

ionic and covalent

What are ionic bonds?

these bonds are formed when atoms transfer electrons to one another and become ions

What are covalent bonds?

these bonds are formed when atoms share electrons with other atoms

What are ionic compounds also known as?

salts

What are ionic compounds formed with?

positively and negatively charged ions

What is one trait of ionic compounds?

dissociate in water/dissolves in water

What are covalent bonded compounds also called?

molecules

Covalent bonds (do/do not) dissociate in water

do not

What is required to break covalent bonds?

chemical reactions

What are two classifications of covalent compounds (molecules)?

polar or nonpolar

What is a nonpolar molecule?

there is no partial positive or negative region on the molecule because atoms share electrons equally

What is a polar molecule?

there is a partial positive and negative region on the molecule because atoms are not shared equally

What does “like dissolves like” refer to?

polar substances(and charged substances, such as ions) like to associate with other polar substances, while nonpolar substances like to associate with other nonpolar substances.

Nonpolar molecules are (hydrophobic/hydrophilic).

hydrophobic

Polar molecules and ions are (hydrophobic/hydrophilic).

hydrophilic

A molecule’s shape determines its _______.

function

Hydrogen bonds are possible when hydrogen is bonded to ______, ______, and ______.

Fluorine, Oxygen, Nitrogen

Hydrogen bonds are (weak/strong)

weak, but many can be collectively strong

What is cohesion?

a property of water — the ability of water molecules to “cling” to each other due to hydrogen bonding

• ex. Water forming droplets

What is adhesion?

a property of water — ability of water molecules to “cling” to other polar surfaces due to hydrogen bonding

• ex. Water drops sticking to glass

What is capillary action?

water’s ability to “climb” narrow spaces

Why does water form droplets?

surface tension; it is the force created from the molecules at the surface of a liquid being attracted to the molecules below the surface

How do organisms maintain normal internal temperature?

organisms are made of mostly water, which absorbs lots of thermal energy without a great change in temperature

How does sweat work?

essentially evaporative cooling in animals; animal’s body heat is used to evaporate the water

Why does ice float?

due to hydrogen bonds, water expands when it freezes

Why is water considered the “universal solvent”?

it has high polarity, which is able to dissolve many different substances

What is the pH value of a neutral solution?

7

What is the pH value of an acidic solution?

<7

What is the pH of a basic solution?

>7