2. Chemistry: Ch 1 Matter and Change

3. Golden Rod Demo Notes Welcome to Chemistry!!!!!

4. What is Chemistry? Activity: Insta-Snow Observing Asking Questions Looking for Answers Asking More Questions Experimenting More Observing What we’re doing-playing with stuff like 8-year- olds...is the root of modern science. Observing the world and trying to figure out what it means is the core of science. We invent theories to explain what we see, hear, and smell. Chemistry (Science) is a process of observing, educated guessing, and testing.

5. Chemistry is Everywhere Everything you hear, see, smell, taste, and touch involves chemistry and chemicals. Chemistry is the study of matter and the changes it can undergo. Chemistry is about composition, structure, function, and interaction of matter. Everything has composition, structure, function, and interaction Matter is anything that has mass and occupies space. All matter is composed of various combinations of elements. The wonder of chemistry is that when these basic particles are combined, they make something new and unique. Chemistry helps us understand the world around us. Understanding the basic properties of matter and learning how to predict and explain how they change when they react to form new substances is what chemistry and chemists are all about. Chemistry is not limited to beakers and laboratories. It is all around us, and the better we know chemistry, the better we know our world. All other sciences (biology, physics, geology, etc) have their basis in chemistry.

6. Chemicals (Substances) Matter with definite composition Either Elements or Compounds Elements: One type of atom Oxygen (O 2 ) Ozone (O 3 ) Copper Compounds: Two or more types of atoms Sodium chloride (table salt) NaCl Ethyl alcohol H 2 O

7. Topics in Chemistry: ABC Chart

8. How does this photo illustrate what chemistry is all about? Chemical reactions of rusting/weathering/maybe a fire in the fireplace Physical states of water Different types of materials: glass, wood, living material, brick, snow

9. The Study of Matter and Change What is Matter? Anything that has mass and takes up space (volume) Stuff Not Matter Light Energy Emotions or Feelings Thoughts Electricity Sound

10. Submicroscopic and Macroscopic Submicroscopic Atomic Level What happens here determines the macroscopic Macroscopic What we observe Determined by the submicroscopic (atomic) Chemist are interested in how the atomic level determines the macroscopic

11. Observation of a Burning Candle

12. Mystery Light Block

13. The Scientific Method The scientific method is a systematic approach used in scientific study, whether it is chemistry, physics, biology, or another science.scientific method To solve problems Not a set of rigid steps It is an organized process used by scientists to do research, and provides methods for scientists to verify the work of others.

14. Observations Gathering Information (Data) using the five senses No trivial or unimportant observations Don’t make inferences or assumptions when you observe –Qualitative data is obtained through observations that describe color, smell, shape, or some other physical characteristic that is related to the five senses.Qualitative data –Quantitative data is obtained from numerical observations that describe how much, how little, how big or how fast.Quantitative data

15. Controlled Experiment A test of a hypothesis Making observations under controlled conditions Where only one variable at a time is changed Systematic approach to test a hypothesis Parts of An Experiment Variables: A condition changed in an experiment Independent Dependent Constants: any factor not changed in an experiment Control: Group/set up that has no changes made to it Conclusion: A judgment based on the observations made in a controlled experiment

16. Independent Variable Changed by the experimenter Allowed to change The Cause in Cause and Effect Manipulated Variable Happens First The water’s temperature increased as more heat was applied. The temperature of the solid caused the density of the solid to change An increase in phosphorous helped the plants to grow taller.

17. Dependent Variable Changes in response to the change in the independent variable Responding Variable Happens second The boiling point increased as salt was added to the water The hamster grew two inches with an increase in the hormone.

18. Control A point of comparison in an experiment The group that does NOT receive the treatment

19. Constants Specifics that remain the same between the control group and the experimental group Only the independent variable should be changed by the experimenter Examples of Constants:

20. Conclusion A conclusion is a judgment based on the information obtained from the experimentconclusion

21. Identify the following Independent Variable Dependent Variable Control Constants Possible conclusion Another hypothesis

22. Experiment Kate noticed that she could dissolve more sugar in the tea when it was warm than when it was ice cold. She wondered if this was true for all solids. She decided to design an experiment to see if water temperature effects how much salt can be dissolved. She chose table salt as her solid to test. She used water as her solvent. Hypothesis: An increase in the temperature of the water will allow more salt to dissolve, She placed 100 mL of water in each of 10 250 mL beakers. She cooled the water in beaker # 1 to 10 degrees C. The water in beaker #2 was 25 degrees C. Beaker # 3 water was heated to 35 degrees C. Beaker # 4 water was heated to 45 degrees C. Beaker # 5 was heated to 55 degrees C.

23. Beaker # 6 65 degrees C Beaker # 7 75 degrees C Beaker # 8 85 degrees C Beaker # 9 95 degrees C Beaker # 10 100 degrees C

24. She added salt to each beaker while using a magnetic stirrer which provided constant and uniform stirring until no more salt would dissolve. She measured and recorded the amount of salt that dissolved in each beaker. Her data is shown below.

25. Data Amount of water 100 mL Temp of Water (degrees C) Grams of salt dissolved 11037 22537 33538 44538 55538 66538 77539 88540 99540 1010040

26. Hypothesis and Experiment Hypothesis: A tentative explanation of observations A tentative answer A statement to be tested by an experiment Example: If I give the fish more hormone then they will grow longer. Experiment: The test of a hypothesis A controlled set of steps to test a hypothesis

27. Theory Vs Hypothesis A theory is a hypothesis that has stood the test of repeated experiments An explanation of results Never proven Can be disproven All theories are hypotheses. (True) All hypotheses can become theories. (True) All hypotheses are theories. (False)

28. Scientific Law Vs Theory Observable Fact True: Always observed No known exceptions No explanation Explanation Tentative Can be disproven

29. Development of a Theory Start with an observation that evokes a question: Broth spoils when I leave it out for a couple of days. Why? Using logic and previous knowledge, state a possible answer, called a Hypothesis: Tiny organisms floating in the air must fall into the broth and start reproducing. Perform an experiment or Test: After boiling some broth, I divide it into two containers, one covered and one not covered. I place them on the table for two days and see if one spoils. Only the uncovered broth spoiled. Then publish your findings in a peer-reviewed journal. Publication: "Only broth that is exposed to the air after two days tended to spoil. The covered specimen did not." Other scientists read about your experiment and try to duplicate it. Verification: Every scientist who tries your experiment comes up with the same results. So they try other methods to make sure your experiment was measuring what it was supposed to. Again, they get the same results every time. In time, and if experiments continue to support your hypothesis, it becomes a Theory: Microorganisms from the air cause broth to spoil. Useful Prediction: If I leave food items open to the air, they will spoil. If I want to keep them from spoiling, I will keep them covered.

30. Notes for Demo Penny in Nitric Acid copper solutions/compounds are blue colored gases are poisonous strong acids are corrosive Copper reacts with nitric acid HNO 3 Indicators of a Chemical Change 1.Production of a gas 2.Production of a solid 3.Temperature change 4.Color change

31. Chemistry is traditionally broken into branches that focus on specific areas such as –Organic chemistry –Inorganic chemistry –Physical chemistry –Analytical chemistry –Biochemistry –Environmental chemistry –Industrial chemistry –Polymer chemistry –Theoretical chemistry –Thermochemistry :

32. This Class HS General Chemistry is Inorganic Inorganic Chemistry:Inorganic Chemistry: the study of non-carbon based compounds Organic Chemistry:Organic Chemistry: Study of matter that contains carbon

33. Technology Application of Science for human benefit Good and Bad Nuclear Technology Good: EnergyBad: Waste Computer Technology Good: CommunicationBad: Wasted Time

34. Pure Science Vs Applied Science Pure Science: For the sake of the knowledge Studying butterflies just to know more Researcher lives on a remote island to daily study the jungle trees Studying ape behavior Applied Science: Using science to solve a particular problem Scientist studying corn in fields to increase the yield for farmers Scientist searching for a cancer cure

35. Why is Pure Research Important? A Base of knowledge when needed Keeps us current General not specific and possible commercial Accidental Discoveries

36. Mass Vs Weight Mass Not influenced by gravity Changes only when amount of matter changes Kilograms or grams Weight Affected by gravity W = mg g= 9.8 m/s 2

37. Your Mass Earth M ass = 60 kg Moon Gravity = 1/6 th the gravity on Earth Mass = 60 kg Not affected by gravity

38. Weight Earth m = 60 kg W = mg W = (6o kg)(9.8m/s 2 ) W = 588 Newtons Moon m = 60 kg W = mg g = 9.8m/s 2 /6 = 1.63 m/s 2 W = (60 kg)(1.63m/s 2 ) W = 98 Newtons

39. Environment with No Gravity Weight only would change You would weigh less Amount of Matter is not affected Mass stays the same

40. Chance Discoveries Discoveries made by accident Not trying to find an answer Examples Velcro Penicillin Teflon Chocolate Chip Cookies The Microwave Oven Artificial Sweeteners Curiosity Drives Discovery

41. Tuesday and Wednesday Pre-Assessment: Password is Lab: Dissolving Salt Electronic Balance Graduated Cylinder Post Lab Q’s: Add One: Do you think particle size affects the rate of a chemical reaction? Why? Lab Equipment Review Using The Presentation: Lab Equipment from my website This Electronic Quiz: http://www.sciencegeek.net/Chemistry/taters/labequipment.htm http://www.sciencegeek.net/Chemistry/taters/labequipment.htm Vocabulary Review/Practice Using Online Resources HW) Equipment Test 25, 27, 31, 33-38, 39-45, 48-51