Mr. Taglia Intro Unit

 The official definition of Chemistry is listed as: “The study of matter and the changes it undergoes…”

 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)

 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

 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

 Color change  Temperature  Presence of a new material  Bubbles/Fizz  Physical characteristics and changes  Odor

 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?

 The scientific method is a systematic approach used in scientific study (chemistry, physics, biology, etc…)

 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..)

 Create a Hypothesis  A Hypothesis is a tentative explanation for what has been observed.

 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…

 Draw a Conclusion  A conclusion is a judgment based on the information  Go back to your hypothesis and see if you were right.

 Theory  A theory is an explanation that has been supported by many, many experiments

 Scientific Law - a relationship in nature that is supported by many experiments.

 Fundamental units (also called base units)  Length = meter (m)  Mass = kilogram (kg)  Time = seconds (s)  Temperature = degrees Kelvin (K)  Number of particles = moles (mol)

 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)

 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 cm 3 = g/cm 3

 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

 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

 Numbers expressed as ? x 10 ?

 Express in scientific notation.  Express 2900 in scientific notation.  In your calculator, type in the number 4.567x10 8.

 Use your calculator to perform the following calculation (3.45x10 12 kg) x (4.3x10 -2 m/s 2 ) Express your answer with the correct units.

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