18. testedmodified
The scientific method is a systematic approach to research
A hypothesis is a tentative explanation for a set of
observations
A law is a concise statement of a relationship between phenomena
that is always the same under the same conditions.
1.3
19. Chemistry is the study of matter and the
changes it undergoes
Matter is anything that occupies space and has mass.
A substance is a form of matter that has a definite composition and
distinct properties.
water, ammonia, sucrose, gold, oxygen
1.4
20. soft drink, milk, solder
cement,
iron filings in sand
A mixture is a combination of two or more substances in which the
substances retain their distinct identities.
Homogenous mixture composition of the mixture is the same
throughout.
Heterogeneous mixture composition is not uniform throughout.
1.4
21. magnet
distillation
Physical means can be used to separate a mixture into its pure
components.
1.4
22. Fractional Distillation Apparatus
12.6
23. An element is a substance that cannot be separated into
simpler substances by chemicalmeans.
27. Water (H2O)
Glucose (C6H12O6)
Ammonia (NH3)
A compound is a substance composed of atoms of two or more elements
chemically united in fixed proportions.
Compounds can only be separated into their pure components
(elements) by chemical means.
1.4
28. 1.4
29. gas
solid
liquid
Three States of Matter
1.5
30. sugar dissolving
in water
ice melting
hydrogen burns in air to form water
Physical or Chemical?
A physical change does not alter the composition or identity of a
substance.
A chemical change alters the composition or identity of the
substance(s) involved.
1.6
31. Extensive and Intensive Properties
An extensive property of a material depends upon how much matter is
is being considered.
mass
32. length
33. volume
An intensive property of a material does not depend upon how much
matter is is being considered.
density
34. temperature
35. color
1.6
36. weight = c x mass
A 1 kg bar will weigh
on earth, c = 1.0
1 kg on earth
on moon, c ~ 0.1
0.1 kg on moon
Matter - anything that occupies space and has mass.
mass measure of the quantity of matter
SI unit of mass is the kilogram (kg)
1 kg = 1000 g = 1 x 103 g
weight force that gravity exerts on an object
1.7
37. Volume SI derived unit for volume is cubic meter (m3)
1 cm3 = (1 x 10-2 m)3 = 1 x 10-6 m3
1 dm3 = (1 x 10-1 m)3 = 1 x 10-3 m3
1 L = 1000 mL = 1000 cm3 = 1 dm3
1 mL = 1 cm3
1.7
38. mass
density =
volume
A piece of platinum metal with a density of 21.5 g/cm3 has a volume
of 4.49 cm3. What is its mass?
m
m
d =
d =
V
V
Density SI derived unit for density is kg/m3
1 g/cm3 = 1 g/mL = 1000 kg/m3
= 21.5 g/cm3 x 4.49 cm3 = 96.5 g
m = d x V
1.7
39. nitric acid
HNO3
carbonic acid
H2CO3
H2SO4
sulfuric acid
An acid can be defined as a substance that yields
hydrogen ions (H+) when dissolved in water.
HCl
Pure substance, hydrogen chloride
40. Dissolved in water (H+ Cl-), hydrochloric acid
An oxoacid is an acid that contains hydrogen, oxygen, and another
element.
HNO3
2.7
41. 2HCl (aq) + Mg (s) MgCl2 (aq) + H2 (g)
2HCl (aq) + CaCO3 (s) CaCl2 (aq) + CO2 (g) + H2O (l)
Acids
Have a sour taste. Vinegar owes its taste to acetic acid.
Citrus
fruits contain citric acid.
Cause color changes in plant dyes.
React with certain metals to produce hydrogen gas.
React with carbonates and bicarbonates to produce carbon
dioxide gas
Aqueous acid solutions conduct electricity.
4.3
42. pH A Measure of Acidity
Solution Is
pH = 7
neutral
acidic
pH < 7
basic
pH > 7
15.3
43. 2.7
44. sodium hydroxide
NaOH
potassium hydroxide
KOH
Ba(OH)2
barium hydroxide
A base can be defined as a substance that yields
hydroxide ions (OH-) when dissolved in water.
2.7
45. Bases
Have a bitter taste.
Feel slippery. Many soaps contain bases.
Cause color changes in plant dyes.
Aqueous base solutions conduct electricity.
4.3
46. Salts
Asalt, is defined as the product formed from the neutralization
reaction ofacids andbases. Salts areionic compounds composed of
cations (positivelycharged ions) andanions (negative ions) so that
the product is electricallyneutral (without a net
charge)
49. Solution
Solvent
Solute
A solution is a homogenous mixture of 2 or more substances
The solute is(are) the substance(s) present in the smaller
amount(s)
The solvent is the substance present in the larger amount
H2O
Soft drink (l)
Sugar, CO2
Air (g)
N2
O2, Ar, CH4
Pb
Sn
Soft Solder (s)
4.1
50. Heterogeneous Mixtures
Colloidal dispersions
Colloids are mixtures in which the particles of one or more
components have at least one dimension in the range of 1 to 10nm,
larger than those in a solution but smaller than those in a
suspension.
51. Colloids are the same as suspensions, except they dont
leave sediments
52. In general, a colloid or colloidal dispersion is a
substance with components of one or two phases.
53. It creates theTyndall effectwhen light passes through it. A
colloid will not settle. Jelly, milk, blood, paint, fog, shampoo,
and glue are examples of colloid dispersions.
