Warm-Up List and Describe 5 Safety Rules that you think should always be followed in the Chemistry lab.

Scientific Inquiry is Complex Designing and Conducting Scientific Investigations Designing and Conducting Scientific Investigations Collecting and Interpreting Data Collecting and Interpreting Data Formulating and Revising Conclusions Using Evidence from Data Formulating and Revising Conclusions Using Evidence from Data Communicating and Defending Scientific Arguments Communicating and Defending Scientific Arguments

What’s the deal with Chemistry? The science of the composition, structure, properties, and reactions of matter, especially of atomic and molecular systems The science of the composition, structure, properties, and reactions of matter, especially of atomic and molecular systems In other words: The study of Matter and the changes that it undergoes In other words: The study of Matter and the changes that it undergoes

Matter & Change Matter is anything that has mass and occupies space. Matter is anything that has mass and occupies space. Solid, Liquid and Gas Solid, Liquid and Gas Therefore everything is matter Therefore everything is matter Chemistry is the study of everything around us and how it changes. Chemistry is therefore the central science. Chemistry is the study of everything around us and how it changes. Chemistry is therefore the central science.

Chapters 1 and 3 Chemistry: The Study Of Matter Part 1

Chemistry is the science that investigates and explains the structure and properties of matter (how matter behaves). Matter and Its Characteristics Matter is the stuff that’s all around you: the metal and plastic of a telephone, the paper and ink of a book, the glass and liquid of a bottle of soda, the air you breathe, and the materials that make up your body. A more formal definition of matter is anything that takes up space and has mass.

Mass is the measure of the amount of matter that an object contains. A balance is used to measure mass. When the amount of matter (mass) is the same on both sides, it balances. Weight is the pull of Earth’s gravity on matter. A scale is used to measure weight. Scales have springs that measure the pull of gravity (weight).

Matter that is large enough to be seen is called macroscopic. All your observations using your five senses are “macroscopic”. Views of Matter The observation “aspirin and sugar are both white solids”, is a macroscopic observation. Atoms are SUB-microscopic! (too small to be seen, even with a microscope!)

Atoms are too small to be seen with visible light. To see with light, (which is a wave), the object must be bigger than the light wave. This “bounces”, or reflects, the light back to your eyes. This is why we can only “see” atoms with electron microscopes. We cannot see atoms with an ordinary microscope using visible light. Visible light wave atom (no reflection) Beam of electrons (reflected)

So, why is this submicroscopic view of matter so important?

aspirinSucrose (sugar) The submicroscopic arrangements of the atoms causes the macroscopic behavior we observe! They contain the same elements!

Classifying Matter One of the goals of science is to “classify” things… to place things that are similar into groups. In Biology, life was classified in Kingdoms as “Animalia”, “Plantae”, “Fungi”, etc… …animals were further classified as “mammals”, “reptiles”, “amphibians”, etc. In chemistry, we need to classify different types of matter in much the same way…

Matter SUBSTANCES always homogeneous, always pure! Heterogeneous Matter: different portions have a different compositions, or makeups. MIXTURES can be heterogeneous or homogeneous, but are NEVER pure! ElementsCompounds gold water Homogeneous Matter: all portions have the same composition, or makeup. Homogeneous mixtures (solutions) Heterogeneous mixtures

The States of Matter Solid Liquid Gas (water vapor) The Earth is the only planet in our solar system where water is found simultaneously in all three phases!

Gases have no definite volume or shape Liquids have a definite volume, but no definite shape Solids have both definite volume and shape!

solid liquid gas melting freezing Boiling, or evaporation condensation sublimation deposition “Phase Change” = a change in the state of matter

Each set of phase changes between the same states of matter OCCUR AT THE SAME TEMPERATURE! For example, water freezes and melts at 0  C! While the melting or freezing is occurring, the temperature stays constant at 0  C The only difference is whether heat is being added or removed! 0ºC meltingfreezing ice water

Scientific models are mental images that help us explain what we see, and are built on experimentation. Experiments require “observations”… …“Qualitative” and/or “Quantitative” observations (A mental “picture”, or “model” of aspirin… the atoms don’t really have these colors, and the atoms aren’t really solid “balls” of matter)

A qualitative observation is made without measurement. An example: “aspirin is a white solid”. Qualitative data— is information that describes “what”… often using the five senses.

For example, analysis would show that aspirin is 60% carbon. Quantitative data contain numbers. They are most often the goal of scientific research. Quantitative observations describe “how much”. A quantitative observation uses measurement. (think “quantity”…amount)

Scientific Methods A typical scientific method includes: making observations, forming a hypothesis, performing an experiment, and arriving at a conclusion. A scientific method is a systematic approach to answer a question or study a situation. asking a question, O.K. let’s check some definitions:

A hypothesis is a possible explanation for what has been observed. (Not a “guess”!) An experiment is a set of controlled observations that test a hypothesis. A theory is an explanation that is used to predict behavior. A theory has been supported by many experiments. A conclusion is a decision based on the results of the experiment. (Hypotheses are never proven, only “supported” by data and experiments!)

A surfer observes the ocean waves breaking… He makes a hypothesis that the waves will begin to break at a new location. He experiments by paddling out to that location His conclusion is based upon his rides -

A scientific law describes a relationship in nature. No explanation is offered – just a description. “All objects in the universe attract each other. The attraction is greater as distance decreases, and as mass increases.” (The Law of Gravitation)

Scientific Research Pure research is done to gain knowledge for the sake of knowledge itself. Applied research is undertaken to solve a specific problem. Technology is the practical use for scientific knowledge.