1. Chemistry Measurement Notes
Chapter 3:
Significant Figures, Scientific Notation,
Metric Conversions

2. Measurement Units: Without units, data has no meaning…. Mass =
Volume =
Length =
Temperature=
Density=
Heat=
Without units, data has no meaning….

3. Uncertainty
When reading a measurement from a device, always estimate _________________
This device measures in increments of 1 degree.
We know that there is at least 3 degrees, we know there is not more than 4, we have to estimate to the tenths place
I’d say 3.8 degrees where _____________________

4. Accuracy vs. Precision Accuracy- Precision-
Example- a substance has a density of 3.00g/mL. In the lab, you find the density to be:

5. Metric Conversions 3 Metric Prefixes you must know:
1 kilo =
100 centi =
1000 milli =
You must also know this:
1 mL=
Setting up conversion factors:
Convert 45 mm to km
Convert 5 m/min to km/hr.

6. Significant Figures (Sig Figs)
All nonzero digits are significant.
Ex:
Zeros to the right of the decimal are significant, but only if there’s a sig fig before.
Zeros to the left of the decimal are NOT significant.
Zeros in-between digits are significant.

7. Sig Figs Continued
When adding/subtracting with sig figs, you must report to the least number of decimal places. used.
Ex:
For multiplying & dividing. Only report to fewest sig figs used.

8. Scientific Notation
Scientific Notation is used to simplify very large or very small numbers.
The only digits used in S.N. are ___________
Ex:
There can only be __________________________

9. Calculating with S.N. When you multiply, When you divide,
Ex:
When you divide,
For addition and subtraction,

10. Celsius to Kelvin

11. Error & Uncertainty in Measurement
Plus/Minus Notation
Percent Error