Biology Chapter 2 test and 3-1 10-2-15 Flashcards
1
Q
What is matter?
A
- anything that occupies space and has mass
2
Q
What is mass?
A
- quantity of matter an object has
3
Q
What are elements?
A
- pure substances that can not be broken down chemically into simpler molecules
4
Q
Where are elements listed?
A
- periodic table
5
Q
What does every atom contain a certain number of?
A
- protons
- neutrons
- electrons
6
Q
Describe neutrons.
A
- neutrons and protons make up nucleus
7
Q
What charge are protons?
A
-positive
8
Q
What charge are electrons?
A
- negative
- reason bonds form between atoms
9
Q
What are electrons?
A
- very small particles that are found on orbitals or energy levels
10
Q
What do electrons allow elements to do?
A
- ‘stick’ together
11
Q
What is the atomic number?
A
- tells us the number of protons (+) and the number of electrons (-)
12
Q
What is atomic mass?
A
- (rounded up) mass of nucleus (# of protons and neutrons)
13
Q
How do you calculate the amount of neutrons in an element?
A
- atomic mass - number of protons
14
Q
What are compounds?
A
- a pure substance made up of 2 or more elements ex. water
15
Q
What are molecules?
A
- simplest part of substance, found in free state (hydrogen)
16
Q
What do electrons help atoms do?
A
- stick to each other and form bonds
17
Q
List the 3 types of bonds from strongest to weakest.
A
- covalent
- ionic
- hydrogen
18
Q
What is a covalent bond?
A
- share electrons (strongest bond) ex. water
19
Q
What are ionic bonds?
A
- transfer electrons (usually particles) are involved- ex NaCl (table salt)
20
Q
What are hydrogen bonds?
A
- weak/break easily
21
Q
What is an ion?
A
- charged particle
22
Q
What is energy?
A
- the ability to do work or cause change (different forms such as…. light, heat)
23
Q
What is free energy?
A
- energy available for work
24
Q
reactant + reactant yields products
A
H₂0 + O₂ -> H₂O₂ (hydrogen peroxide)
25
What are exergonic reactions?
- hot to touch
| - release of free energy
26
What are endergonic reactions?
- cold to touch
- absorption of free energy
R + R P
27
What is activation energy?
- amount of energy required to start a chemical reaction
28
What are catalysts?
- reduce the amount of energy needed- thus speeds up the reaction
29
What are enzymes?
- biological catalysts
30
Why do oxidation reactions happen?
- because of transfer of electrons
31
What is an oxidation reaction?
- loses an electron becoming positively charged
32
What is a reduction reaction?
- gains an electron becoming more negative
33
oxidation and reduction happen together
- t swiftttt
34
LEO says GER
loses electrons oxidized - gains electrons reduced
35
What are the 3 states of matter?
- solid, liquid, gas
36
How do catalysts affect reactions?
- speed them up
37
What is an enzyme?
- biological catalyst
38
What is the difference between products and reactants?
- products- when two reactants are combined
| - reactants- form products
39
What is a solution?
- a mixture in which one or more substances are uniformly distributed in another substance
40
What is a solute?
- being dissolved
41
What is a solvent?
- doing the dissolving
42
What is the dissociation of water?
- how water breaks down
43
What does water break down into?
- Hydroxide ions OH- (minus not a dash)
| - Hydrogen ions H+
44
When do hydrogen ions (H3O+) form?
- when a hydrogen ion bonds with a water molecule
45
What does the pH scale compare?
- the amount of hydronium ions or hydroxide ions in a solution
46
What does more OH- indicate?
- a base
47
What does more H3O+ (H+) molecules indicate?
- an acid
48
What does the pH scale range from?
- 0-14
| - can have decimals such as 0.2
49
On pH scale do small changes make a big difference?
- yes
50
What is neutral on the pH scale?
- 7 ex. water
- below 7- acidic
- above 7- basic or alkaline
51
What are buffers?
- help neutralize acids or bases to help living things
52
What is a universal solvent?
- water
| - dihydrogen monoxide H₂O
53
What is a polar compound?
- there is an uneven distribution of electrons between its oxygen and hydrogen atoms
54
Water can also...
- heat up and cool down quickly due to hydrogen bonds
55
What is adhesion?
- the attraction between molecules of different substances
56
What is capillary action?
- allows water to move up tubes, such as roots, against the force of gravity
57
What is cohesion?
- the attraction between molecules of the same substance
58
What does cohesion result in?
- drops of water and surface tension
59
What is surface tension?
- a force exerted by the surface of the water on the particles below
60
What does cohesion allow for?
- pond swimmers, dirt bikes, and the Jesus Christ Lizard to be able to stay on top of the water
61
What happens when water freezes?
- it expands
62
Describe ice.
- less dense than liquid water and it also floats when it forms
- this acts as an insulator for ponds
63
What happens when ice expands?
- it can also break rock which eventually forms soil or potholes!
