10/3(Fri) & 10/6 (Mon)
Warm up # 2 : Balancing equation
Balance the equations, then determine the types
of reaction:
__Zn + __HCl → __ZnCl2 + __H2
__C2H6 + __O2 → __CO2 + __H2O
IDENTIFY the number of sig fig, then ROUND to 3 sig fig:
0.002100
2351.0
9000000.
FIT next week
 Tuesday: tutorials—metric conversions and
calculations with sigfigs
 Wednesday: balancing equations only!
Calculations with sig. figs.
 Rule for Multiplication and Division:
Answer will have the same number of significant
figures as the number with the fewest sig figs.
Step 1: Do the basic calculation
Step 2: Identify the number of sig figs of ALL the
numbers in the question, then find the one with the
FEWEST sig. figs.
Step 3: Round the your final answer to the number of
sig. figs. you just identified in step 2.
Examples
 Examples:
1) 4.1 x 5560 = 22796 ~ 23000
2) 1128.23 ÷ 1000 = 1.12823 ~ 1
3) 5.0 x 104 = 1.5527905 … x 101
3.22 x 103
~ 1.6 x 101
Metric Conversions
UNIT ANALYSIS
Metric Base Units
Length base unit: meter
Volume base unit: liter
Time base unit: second
Metric Prefixes
Prefixes are used to “modify”
base units.
Examples: kilo, pico, etc
How to Read your Conversion Chart
How many picometers are in
1 meter?
How many nanograms are in
1 gram?
The Set-up
 Always set up these problems in the
same format!
𝑢𝑛𝑘𝑛𝑜𝑤𝑛
=
𝑔𝑖𝑣𝑒𝑛
(
𝑐𝑜𝑛𝑣𝑒𝑟𝑠𝑖𝑜𝑛
)
𝑓𝑎𝑐𝑡𝑜𝑟
Remember to use units!
The units of the given should match the units of the
BOTTOM of the conversion factor so they cancel out!
Example 1
 How many meters are in 574.5 Gigameters?
Calculator Stuff
Divide:
4.9 x 10-11
9.6 x 109
Example 2
 How many teraliters are in 0.01242 liters?
Homework
 Sig. Fig. Calculation Practice
 Metric conversion problems
 Next class:
 Quiz: Types of reaction, Balancing equations, Sig fig
calculations and Metric conversions
 Thurs/Fri: Test over the same stuff as the quiz!