1. Introduction to Chemistry Chapters 1&3

2. Pre-class Activity Chemistry is the study of matter and the changes that it undergoes. What is matter? Be prepared to give two examples of matter that can be found in the classroom

3. Chemistry and Matter Chemistry is the study of matter and the changes that it undergoes. Anything that has mass and takes up space A measurement that reflects the amount of matter

4. Questions What in the universe isn’t matter? Energy Why aren’t the terms mass and weight interchangeable? Weight is not only a measure of the amount of matter, but also a measure of the effect that gravity has on matter

5. Scientific Method – A Systematic Approach OBSERVATIONHYPOTHESISEXPERIMENTTHEORY Draw conclusions and revise hypothesis Theories are supported by many experiments SCIENTIFIC LAW

6. Theory vs. Law Arise following many, many experiments Provides an explanation of what occurs in nature Merely states what occurs in nature

7. Observations Hot 300 o Qualitative vs. Quantitative Temperature Height Mass Length

8. Experiments A set of controlled observations that test a hypothesis. Key Terms Variable: A quantity or condition that can have more than one value Independent Variable: A variable that is changed by the investigator in an experiment Dependent Variable: A variable the changes in response to the independent variable Control: A standard for comparison

9. Experimental Design Example The Effect of Temperature on the Respiration Rate of Fish Temp ( o C) Respiration Rate What is the dependent variable? What is the independent variable? What would be an appropriate control? What is the relationship between respiration rate and Temperature?

10. Pure vs. Applied Research Gaining knowledge for the sake of knowledge Vs. Gaining knowledge to solve a specific problem

11. Pre-class Activity A scientist owns fish that are very sensitive to changes in temperature. One morning, after a huge storm, he came into the lab only to find that all the fish in his tank were dead. He suspected that there might have been a power outage due to the storm, in which the power to the heater may have been interrupted. To test this, he measured the temperature of the tank, only to find that it is normal. Identify the observation, hypothesis and experiment in the paragraph above. Does the result of the experiment support the hypothesis? Homework: Continue with HW assignments 1,2,3. Homework Assessment #1 – Tuesday 9/13, Element Quiz – Monday 9/12

12. Mrs. Pav’s Milk Lab Write-Up Pupose: To determine if milk type affects the migration time of food coloring in the milk experiment Hypothesis: If whole milk is substituted for skim milk in the milk experiment, the food coloring will migrate slower. Materials: In addition to materials listed for the milk lab, whole milk was added Procedure: Refer to written procedure for the milk lab. The migration time of food coloring was measured by using a stop watch to record the time that it took for the food coloring to migrate to the edge of the petri dish. Results: The time for the control (skim milk) was 4.8 seconds.The time for the experimental group (whole milk) was 3.2 seconds. Conclusions: The hypothesis was confirmed by the data because the migration time of food coloring increased for whole milk as compared to skim milk

13. Pre-class Activity Physical properties of matter are those properties that can be observed or measured without changing the composition of the matter. The ability of a substance to combine with or change into one or more other substances is called a chemical property Does the photograph to the right depict a physical property of water or a chemical property of water? Homework (Due 9/22) Start/Continue Working on chapter(s) review assignment

14. States of Matter (Physical Forms) StateShapeVolumeCompressibility Solid Liquid Gas Definite Indefinite Definite Indefinite Incompressible Nearly Incompressible Compressible

15. Physical Properties of Matter Physical properties of matter are those properties that can be observed or measured without changing the composition of the matter.

16. Extensive vs. Intensive Properties Extensive properties are dependent on the amount of matter present Intensive properties are independent of the amount of matter present.

17. Classification of Matter Matter SubstancesMixtures Contains only one type of matter. AKA pure substances Contains more than one type of matter. Physical Change

18. A change which alters a substance without changing its composition

19. Mixtures Matter SubstancesMixtures Physical Change HomogeneousHeterogeneous Constant composition throughout. AKA solutions Not well blended. Individual components remain distinct

20. Chemical Properties The ability of a substance to combine with or change into one or more substances is called a chemical property A chemical property cannot be observed unless a substance undergoes a chemical change (changes into a new substance)

21. Substances Matter CompoundsElements SubstancesMixtures Physical Change HomogeneousHeterogeneous A chemical combination of two or more different elements Chemical Change A pure substance that can not be broken down in to simpler substances by physical or chemical means

22. Separation Techniques Chromatography: Separates the components of mixtures (mobile phase) on the basis of the tendency of each to travel or be drawn across the surface of another material.

23. Separation Techniques Distillation: Separates homogeneous mixtures based on differences in boiling points.

24. Separation Techniques Filtration: Uses a porous barrier to separate a solid from a liquid in a heterogeneous mixture.

25. Separation Techniques Crystallization: A technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance

26. Pre-Class Question Which of the following photographs represent physical change?

27. Review What is required to separate a mixture into individual substances? A Physical Change What is the key difference between a physical change and a chemical change? During a physical change the composition of matter stays the same. The composition of a substance is altered as a result of a chemical change. Homework Be prepared for homework quiz #2 on Wednesday 9/21

28. Evidence of a Chemical Reaction Change in color Change in temperature Endothermic vs. Exothermic Production of a gas Production of a precipitate Absorption of energyRelease of energy Two liquids are combined and a solid is formed

29. Subscript Coefficient Law of Conservation of Mass “Mass is neither created or destroyed in a chemical reaction, it is conserved” 47g + 32g 79g

30. Compounds Law of Definite Proportions: Elements combine in definite proportions by mass. The percent by mass of each element in a compound will be the same regardless of the quantity of the compound.

31. Compounds Law of Multiple Proportions: When different compounds are formed from the same elements, different masses of one element combine with the same relative mass of the other element in small whole numbers. FeBr 2 and FeBr 3