Chemistry Test Flashcards
(31 cards)
Element
A substance that can’t be broken down into simpler substances
How many elements occur naturally?
92
How many elements are essential to life?
25
What are the 4 most abundant elements on earth from most to least? What are their percentages?
Oxygen- 65%
Carbon- 16.5%
Hydrogen- 9.5%
Nitrogen- 3.5%
What is the smallest unit of an element that still has properties of that element?
Atom
Define compound
Two or more elements chemically combined in a fixed ratio
What are covalent bonds?
When 2 atoms share one or more pairs of electrons
Give an example of a covalent bond
Water (is also polar)
Life depends on what?
Chemistry
What is an ionic bond?
When one atom loses an electron and the other atom gains an election
Another way to think of an ionic bond
Think of it as tug of war, they’ll always share that electron
What will an ionic bond form? Give an example
A crystal such as salt
What is a hydrogen bond?
A chemical bond in which a hydrogen atom of one molecule is attracted to an electronegative atom, especially nitrogen, oxygen, or fluorine
Give an example of a hydrogen bond
Water
Which bonds break easily but also forms easily?
Hydrogen bonds
List the 4 states of matter
- Solid
- Liquid
- Gas
- Plasma
What’s activation energy?
The amount of energy required to start a chemical reaction
Define solution
The solute in the solvant
What would be the solute in koolaid?
The koolaid powder
What would be the solvent in koolaid?
The water
What’s a suspension?
When the substance floats in water but gradually sinks to the bottom
Give an example of a suspension
Snowglobe
What’s a colloid?
Particle substance that floats but never sinks or settles out
Example of a colloid
Cherry jello in water
