The Beginning
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Identification/usage of glassware and
equipment
When diluting acids ALWAYS add the
acid to the water to prevent
spattering due to heat build up in the
solution.
When transferring solids use a
spatula/scoopula and NEVER use your
hands.


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To prevent spattering when
transferring liquids one may use a
glass rod near the mouth of the
reagent bottle.
NEVER heat a stoppered piece of
glassware!
Define the term meniscus: Curve that
forms at the top of a liquid in a glass
container due to adhesion of particles
to the container.

Determining percentage error in an experiment:
%error = (measured value - accepted value)
accepted value
x100%
Example: Determine the percent error in an
experiment in which the experimental value
for volume is 21.20mL and the accepted
value is 22.4mL.
Table T has various formulas.
 What is Scientific Notation? number
expressed as the product of
two (2) factors:
1st: a number from 1 – 9
2nd: a power of 10

Why would we put numbers into Scientific
Notation? To simplify larger
numbers or very small numbers
Convert the following into
scientific notation:
602000000000000000000000
.000475
 When
using instruments with indicated markings,
all indicated values are certain. An estimated
value between two markings is said to be
uncertain.
include ALL certain
digits and one uncertain digit, no
more no less!
 Significant
 Example:
figures:
Which numbers are certain in 7.15cm?
How many significant figures does it contain?
 All
NON-ZERO numbers are significant
 Zero
 it
is significant if:
is between two (2) non-zero
numbers [2007]
 whenever you see a decimal
point in a number, find the first
number other than zero and
count [2.00]
Zero
is NOT significant if:
 it
serves only to hold the place of a
decimal [0.239 or 20770]
NOTE:
if a decimal point follows, a zero
becomes significant [20770.]
The
answer is rounded to be no more
precise than the least precise
measurement. Look at the decimal
place it goes to.
Example: Add the following and
round to the correct degree of
significance. 32.34g + 2.6g +
1.3412g
Example:
86.3mL
Subtract 531.46mL –
Answers
should contain no more (no
less) significant figures than the
least precise measurement.
Example: Multiply 24.24cm x
43.9cm
Example:
Divide 5.1g/213L
 What
is a unit? An indicator for the
form of measurement used [cm, L]
Note: Selected units in chemistry can be
found on Table D
 Why is it necessary to use units in any
scientific measurement? To compare
measurements to make them make
sense Example: How tall are you? [6
what? Eggs, meters, pounds?]
 Examples
of units in Tools needed for
measure:
 4g
mass
 75mL
volume
 15cm
length
measure:
Balance
Graduated
cylinder
Ruler
Table D

Prefix
Factor
Decimal Places Symbol

kilo
103
3
k


m,L,g
centi
100
10-1
0
-1
m,L,g
c

milli
10-3
-3
m

micro
10-6
-6


nano
10-9
-9
n

pico
10-12
-12
p
 Note
the appropriate factor and number
of places that you must shift the decimal
point when converting: (make an L or a 7)
moving the decimal the total number of
places (ignoring sign).
 For Example: to convert from nanograms
to kilograms you will move 12 spaces to
the left (9+3=12).
Now using the above table and "sliding decimal rule", perform the
following conversions:
1) 460 g= __________mg 6) 1.30 L= _________mL
2) 312 cm = __________m 7) 3.02 g= __________kg
3) 1002 mL= __________L 8) 0.013 g= __________g
4) 100 kg= ___________g 9) 0.027 cm= ________km
5) 8.23 m= __________mm 10) 560 g= __________kg
Precision:
The reproducibility and
the reliability of data during multiple
trials of any one experiment.
Accuracy: The nearness to the
correct or accepted measurement.

Measured
lab data should be
accurate and precise
Measurements
that are showing
precision in data but are not
accurate could indicate problems
with instruments, contaminated
materials etc. The reproducible
results indicate a careful worker.