the chemistry of life

Question 1

what is matter?

Answer 1

the universe consists of matter which is moved around by energy.
matter occupies space and has a mass.
composed of elements

Question 2

what are the 3 states of matter?

Answer 2

solid-definite shape and volume
liquid-definite volume , flows to fill space
gas-no defined shape or volume

Question 3

what is energy?

Answer 3

energy is the ability to put matter into motion

capacity to do work

Question 4

what is the difference between kinetic and potential energy?

Answer 4

kinetic - is that which moves things

potential- stored energy.when the energy is released it becomes kinetic energy.

Question 5

what are some forms of energy?

Answer 5

chemical energy- stored in chemical bonds- ATP
electrical energy-movement of charged particles- nervous system
mechanical energy- energy directly involved in moving matter
radiant energy-energy that travels in waves

Question 6

what are elements made of?

Answer 6

composed of atom.

Question 7

what is the size of the smallest element?

Answer 7

smaller than 0.1nm

Question 8

what is the size of largest element?

Answer 8

0.5nm

Question 9

what are the 4 elements that make up 96.1% of our body?

Answer 9

C , O , H , N

Question 10

how do elements differ from each other?

Answer 10

elements differ from each other by the number of protons, neutrons and electrons.

Question 11

what is an isotope?

Answer 11

same number of electrons and protons but different number of neutrons.
each element has at least 2 isotopes.

Question 12

what are molecules of an element?

Answer 12

when atoms of same element combine

e.g. H2 S8

Question 13

what are molecules of a compound?

Answer 13

different kind of atoms combine.

e.g. H20

Question 14

what are mixtures?

Answer 14

2+ components physically intermixed

Question 15

what are the three types of mixture?

Answer 15

1. solution
2. colloids
3. suspensions

Question 16

what is the difference between compound and mixture?

Answer 16

.no chemical bond in mixture
.mixture can be separated physically via evaporation or filtering or straining
.compounds need chemical binds to be broken to separate
.compound is always homogenous
.mixture can be heterogenous or homogenous.

Question 17

what are the three types of chemical bonds? and what do they do?

Answer 17

.ionic
.covalent
.hydrogen
they make sure that the atom is stable with 8 electrons in its valence shell

Question 18

what does each electron shell represent?

Answer 18

each electron shell represents different energy level.
electrons therefore have potential energy
electron further away from nucleus has most potential energy.

Question 19

what is ionic bonding?

Answer 19

two oppositely charged ions attract.

intermediate strength

Question 20

what is covalent bonding?

Answer 20

electrons shared between two atoms.
has the strongest bonding
-single bond
-double bond
-triple bond

Question 21

what are non polar molecules?

Answer 21

electrons are shared equally between both atoms

Question 22

what are polar molecules?

Answer 22

electrons shared non equally between both atom

creation of dipole

Question 23

what is electronegativity?

Answer 23

measure of electron sharing ability between atoms.

Question 24

what are hydrogen bonds?

Answer 24

attraction between a H atom and an electronegative atom.

weakest bond.

Question 25

what are chemical reactions?

Answer 25

these occur when electrons are gained or lost | it also occurs when chemical bonds are formed or rearranged or broken.

Question 26

what are the 3 types of chemical reaction?

Answer 26

.synthesis-anabolic .decomposition- catabolic .displacement/exchange

Question 27

what is a synthesis reactions?

Answer 27

smaller particles are bonded together to form larger more complex molecule. e.g. amino acids joined to form a protein molecule. A+B ---> AB

Question 28

what is a decomposition reaction?

Answer 28

large bonds are broken to form small particles. e.g. glycogen broken down to form glucose. AB ---> A+B

Question 29

what is a displacement reaction?

Answer 29

bonds are both made and broken | AB+C --->AC+B

Question 30

what is a redox reaction?

Answer 30

oxidation and reduction state of atom is changed

Question 31

what is oxidation?

Answer 31

loss of electron

Question 32

what is reduction?

Answer 32

gain of electrons

Question 33

what is exergonic?

Answer 33

chemical reaction that releases energy can be catabolic or oxidative.

Question 34

what is endergonic?

Answer 34

chemical reaction that absorbs energy can be anabolic or reduction

Question 35

what are the factors that influence chemical reaction rates?

Answer 35

.temperature .concentration .particle size .catalysts

Question 36

what bonds do all organic compounds have?

Answer 36

all organic compounds are covalently bonded.

Question 37

what are the properties of water?

Answer 37

``` . high heat capacity . high heat of vaporisation . essential reactant in many reactions .universal solvent - due to being a dipole water is compressible ```

Question 38

what are salts?

Answer 38

salts are ionic compounds. when salts are dissolved in water , they dissociate into ions. all ions are electrolytes in solution e.g na and k have electrical properties in nerve impulse transmission and muscle contraction

Question 39

what are acids?

Answer 39

acids release hydrogen ions when dissolved in water and anions they are proton donors they are also electrolytes

Question 40

what are bases?

Answer 40

they dissociate in water and release hydroxide ions. they bind to hydrogen ions. bases can reduce the acidity of a solution by reducing hydrogen ions.

Question 41

what is a ph scale?

Answer 41

acidity refers to free hydrogen ions in a solution.

Question 42

what are buffers?

Answer 42

solution that minimises ph changes when a small amount of acid or base is added.

Question 43

what organic compounds?

Answer 43

organic compounds contain carbon. | e.g. lipids , proteins , carbohydrates

Question 44

how are organic compounds made?

Answer 44

made by dehydration process/ condensation

Question 45

how are organic compounds broken?

Answer 45

they are broken by hydrolysis

Question 46

What is radioactivity?

Answer 46

atomic delay

Question 47

What is atomic delay?

Answer 47

mini-explosion from radioisoptopes alpha particles beta particles gamma rays

Question 48

What are radioisotopes?

Answer 48

unstable dangerous spontaneously decompose releasing energy such as alpha beta and gamma rays

Question 49

What is a valence shell?

Answer 49

these electrons in the outermost energy level that take part in chemical bonding