1. Mr. Taglia
Welcome to Chemistry

2. What is Chemistry? The official definition of Chemistry is listed as:
“The study of matter and the changes it undergoes…”

3. What is matter? Matter is anything that has mass and takes up space.
Mass is a measurement that reflects the amount of matter. (usually measured in grams)
Volume is the amount of space matter takes up. (usually measured in Liters or milliliters)

4. Properties of Matter
All different forms of matter possess a set of chemical and physical properties
Physical- what we can observe with our senses alone…
Chemical- how a type of matter might chemically interact with other types

5. What changes can matter undergo?
Matter can change its structure and its composition
Changes in the structure and composition of matter lead to changes in the properties of the matter.
Two types of changes are:
Chemical Changes – changes in composition
Physical Changes – changes in form
Highlight property changes of the burned match. It’s now brittle, color is different, etc… STOP
Even the oxygen that was in the air has changed its structure, composition, and therefore its properties.

6. What observations can we make?
Color change
Temperature
Presence of a new material
Bubbles/Fizz
Physical characteristics and changes
Odor

7. Conservation of matter
Mass is neither created nor destroyed during a chemical reaction….
***~Law of Conservation of Mass~***
So where does it go if the starting and ending masses are different?

8. Scientific Method
The scientific method is a systematic approach used in scientific study (chemistry, physics, biology, etc…)

9. Steps of the Scientific Method
Observation
Scientific study begins with an observation.
It is simply the act of gathering information
Qualitative information - color, odor, shape, and other physical characteristics
Quantitative data - numerical information (temperature, pressure, volume, quantity, etc..)

10. Steps of the Scientific Method
Create a Hypothesis
A Hypothesis is a tentative explanation for what has been observed.

11. Steps of the Scientific Method
Conduct an experiment to test the hypothesis…
Independent variable - the variable that you plan to change and control
Dependent variable - the variable whose value changes in response to a change in the independent variable (Usually a measurement)
Record Data & Observations…

12. Steps of the Scientific Method
Draw a Conclusion
A conclusion is a judgment based on the information
Go back to your hypothesis and see if you were right.

13. Building a Theory Theory
A theory is an explanation that has been supported by many, many experiments

14. An Undisputed Law…
Scientific Law - a relationship in nature that is supported by many experiments.

15. SI (System International) Base Units
Fundamental units (also called base units)
Length = meter (m)
Mass = kilogram (kg)
Time = seconds (s)
Temperature = degrees Kelvin (K)
Number of particles = moles (mol)
Other fundamental units include Temperature (K), Electric current (A), Luminous Intensity (candela (cd)), Number of particles (mole)
These are the seven fundamental properties upon which all measurements are based.

16. Derived Units Derived units - are combinations of fundamental units
Density - a ratio that compares the mass of an object to its volume. Units are often grams per milliliter (g/mL)

17. Let’s Practice Density
Reference Tables Table T (first equation)
If a sample of wood has a mass of 125 g and a volume of 132 mL, what is its density?
Solution
Density = mass / volume
=125 g / 132 cm3
= g/cm3

18. Accuracy Reference Tables Table T
Accuracy is the extent to which a measured value agrees with the standard or accepted value.
Accuracy is measured using percent error
% error = [(measured value - accepted value) / accepted value] x 100
Reference Tables Table T

19. Precision
Precision is the degree of exactness (if that’s a word) to which the measurement of a quantity can be reproduced
Precision is linked to significant figures
Significant figures includes all known digits

20. Scientific Notation Numbers expressed as ? x 10? Where:
M is the “mantissa”, a number between 1 and 10. The mantissa must contain the correct number of sig figs.
n is the exponent, an integer

21. Let’s Practice Express 0.0000578 in scientific notation.
In your calculator, type in the number 4.567x108.

22. One more thing…
Use your calculator to perform the following calculation
(3.45x1012 kg) x (4.3x10-2 m/s2)
Express your answer with the correct units.

23. Temperature

24. Temperature Conversion…
Going from degrees Celsius to Kelvin.
Use the formula on Table T :
K = °C + 273
Try These Conversions:
a) 30°C to Kelvin…
b) 180 K to Celsisus…