Chemistry for Biology Biology ~ Edgar
Dec 22, 2014
True or False
• Table salt, water, and carbon are all compounds.
• The smallest particle of an element is a molecule.
• A bathtub full of lukewarm water may hold more heat than a teakettle full of boiling water.
• If the atoms in a molecule share electrons equally, the molecule is said to be non-polar.
• Ice floats because water molecules in ice are more tightly packed then in liquid water.
• Atoms in a water molecule are held together by the sharing of electrons.
• If solution-A has a pH of 2 and solution-B has a pH of 5 then solution-B is a stronger base then solution-A
• An atom that has gained or lost electron is called an ion.
• Hydrogen bonds are stronger then covalent bonds.
• Water is a good solvent in living organisms.
LE 2-4a
2
2
2
Protons
Neutrons
Electrons
Helium atom
Massnumber = 4
6
6
6
Protons
Neutrons
Electrons
Carbon atom
Massnumber = 12
Electroncloud
Nucleus
2e–
6e–
LE 2-13
Hydrogen bond
Ice
Hydrogen bonds are stable
Liquid water
Hydrogen bondsconstantly break and re-form
LE 2-15
Acidic solution
OH
H
HH
HOH
H H
H
OH
OH
OH
OH
OH
H
H
H
H
HH
I ncr
ea
sin
gl y
AC
IDI C
(Hi g
he
r c
on
c en
tra
t io
n o
f H
)Neutral solution
OH
OH
OH
OH
OH
OH
H
H
Basic solution
NEUTRALH
pH scale
Lemon juice, gastric juice
Grapefruit juice, soft drink
Tomato juice
Human urine
Pure water
Human blood
Seawater
Milk of magnesia
Household ammonia
Household bleach
Oven cleaner
Incr
ea
sin
gl y
BA
SIC
(Lo
we
r c
on
cen
tra t
i on
of
H )