Chapter 1 Introduction to Chemistry

Scientific Method Experiment Hypothesis Observation Theory/Law

Scientific Method Experiment – Physical procedure used to test an idea Hypothesis – an educated guess Observation – something perceived that causes curiosity Theory/Law – witnessed over and over always same results

Scientific Method 1) Observation – something perceived that causes curiosity 2) Hypothesis – an educated guess 3) Experiment – Physical procedure used to test an idea 4) Theory/Law – witnessed over and over always same results

5 Branches of Chemistry Analytical Chemistry Biochemistry Inorganic Chemistry Organic Chemistry Physical Chemistry

5 Branches of Chemistry 1) Most carbon-containing chemicals 2) In general, matter that does not contain carbon 3) The behavior and changes of matter and the related energy changes 4) Components and composition of substances 5)Matter and processes of living organisms

5 Branches of Chemistry 1) Most carbon-containing chemicals Organic 2) In general, matter that does not contain carbon Inorganic 3) The behavior and changes of matter and the related energy changes Physical 4) Components and composition of substances Analytical 5)Matter and processes of living organisms Biochemistry

Branches of Chemistry BranchAreas of EmphasisExamples Organic Chemistry Most carbon-containing chemicals Pharmaceuticals, plastics Inorganic Chemistry In general, matter that does not contain carbon Minerals, metals and nonmetals, semi- conductors Physical Chemistry The behavior and changes of matter and the related energy changes Reaction rates, reaction mechanisms Analytical Chemistry Components and composition of substances Food nutrients, quality controls BiochemistryMatter and processes of living organisms Metabolism, fermentation

Chemistry and Matter Chemistry The study of matter and the changes that it undergoes Matter Anything that has mass and takes up space Mass A measurement of the amount of matter in an object However, everything is not made of matter Heat, light, radio waves, and magnetic fields are not made of matter

Chemistry and Matter (Continued) Why does scientists measure matter in terms of mass, and not in terms of weight? Your body is made of matter and you usually weigh yourself in pounds Weight is a measure of the amount of matter in your body Weight also includes the effect of Earth’s gravitational pull on your body This force is not the same everywhere on Earth Scientists use mass to measure matter instead of weight because they need to compare measurements taken in different locations

Chemistry and Matter (continued) Matter Made up of particles, called atoms, that are so small they cannot be seen with an ordinary light microscope The structure, composition, and behavior of all matter can be explained by atoms and the changes they undergo Because there are so many types of matter, there are many areas of study in the field of chemistry

Branches of Chemistry BranchAreas of EmphasisExamples Organic Chemistry Most carbon-containing chemicals Pharmaceuticals, plastics Inorganic Chemistry In general, matter that does not contain carbon Minerals, metals and nonmetals, semi- conductors Physical Chemistry The behavior and changes of matter and the related energy changes Reaction rates, reaction mechanisms Analytical Chemistry Components and composition of substances Food nutrients, quality controls BiochemistryMatter and processes of living organisms Metabolism, fermentation

Scientific Methods Scientific method A systematic approach used to answer a question or study a situation An organized way for scientists to do research A way for scientists to verify the work of other scientists Typically includes making observations, forming a hypothesis, performing an experiment, and arriving at a conclusion

Scientific Method (continued) Observations Scientific study usually begins with observations A scientists will begin with qualitative data Information that describes color, odor, shape, or some other physical characteristic that relates to the five senses Scientists also use quantitative data Data that is numerical It tells how much, how little, how big, or how fast

PRACTICE PROBLEMS 1. Identify each of the following as an example of qualitative data or quantitative data. a. Taste of an apple b. Mass of a brick c. Speed of a car d. Length of a rod e. Texture of a leaf f. Weight of an elephant

PRACTICE PROBLEMS 1. Identify each of the following as an example of qualitative data or quantitative data. a. Taste of an apple – Qualitative data b. Mass of a brick c. Speed of a car d. Length of a rod e. Texture of a leaf f. Weight of an elephant

PRACTICE PROBLEMS 1. Identify each of the following as an example of qualitative data or quantitative data. a. Taste of an apple – Qualitative data b. Mass of a brick – Quantitative data c. Speed of a car d. Length of a rod e. Texture of a leaf f. Weight of an elephant

PRACTICE PROBLEMS 1. Identify each of the following as an example of qualitative data or quantitative data. a. Taste of an apple – Qualitative data b. Mass of a brick – Quantitative data c. Speed of a car – Quantitative data d. Length of a rod e. Texture of a leaf f. Weight of an elephant

PRACTICE PROBLEMS 1. Identify each of the following as an example of qualitative data or quantitative data. a. Taste of an apple – Qualitative data b. Mass of a brick – Quantitative data c. Speed of a car – Quantitative data d. Length of a rod – Quantitative data e. Texture of a leaf f. Weight of an elephant

PRACTICE PROBLEMS 1. Identify each of the following as an example of qualitative data or quantitative data. a. Taste of an apple – Qualitative data b. Mass of a brick – Quantitative data c. Speed of a car – Quantitative data d. Length of a rod – Quantitative data e. Texture of a leaf – Qualitative data f. Weight of an elephant

PRACTICE PROBLEMS 1. Identify each of the following as an example of qualitative data or quantitative data. a. Taste of an apple – Qualitative data b. Mass of a brick – Quantitative data c. Speed of a car – Quantitative data d. Length of a rod – Quantitative data e. Texture of a leaf – Qualitative data f. Weight of an elephant – Quantitative data

Scientific Method (continued) Hypothesis A possible explanation for what has been observed Based on the observations of ozone thinning and CFC buildup in the atmosphere, the chemists Mario Molina and F. Sherwood Rowland hypothesized that CFCs break down in the atmosphere due to the Sun’s ultraviolet rays They further hypothesized that a chlorine particle produced by the breakdown of CFCs could break down ozone

Scientific Method (continued) Experiment A set of controlled observations that test a hypothesis In an experiment, a scientist will set up and change one variable at a time A variable is a quantity that can have more than one value Independent variable The variable changed in an experiment Dependent variable The variable that you watch to see how it changes as a result of your changes to the independent variable

Scientific Method (continued) Experiment (continued) Example: If you wanted to test the effect of fertilizer on plant growth, you would change the amount of fertilizer applied would be the independent variable and plant growth would be the dependent variable Many experiments also include a control A standard for comparison In the example above, plants to which no fertilizer is applied

Scientific Method (continued) Conclusion A judgment based on the data obtained in the experiment If data supports a hypothesis, the hypothesis is tentatively affirmed Hypotheses are never proven; they are always subject to additional research If additional data do not support a hypothesis, the hypothesis is discarded or modified Most hypotheses are not supported by data Whether the hypothesis is supported or not, the data collected may still be useful Data from many experiments can be used to form a visual, verbal, and/or mathematical explanation called a model of the phenomenon be studied

Scientific Method (continued) Theory An explanation that has been supported by many experiments State broad principles of nature Theories are the best explanations of phenomena that scientists have at any given time, they are always subject to new experimental data and are modified to include new data Scientific law Describes a relationship in nature that is supported by many experiments and for which no exception has been found Scientists may use models and theories to explain why this relationship exists

1.Draw a particle that consists of 1 triangle. 2.Draw a particle that consists of 1 triangle and 2 squares.

1.Draw a particle that consists of 1 triangle. 2.Draw a particle that consists of 1 triangle and 2 squares.

1.Atom or molecule? 2.Chemical formula? 1.Atom or molecule? 2.Chemical formula? T and Sq

1.Atom or molecule? element 2.Chemical formula? T 1.Atom or molecule? compound 2.Chemical formula? TSq 2

1.Write the chemical formula for a beaker containing the 4 particles below

1.Write the chemical formula for a beaker containing the 2 particles below Mixture T & TSq 2 No chemical bond

Identify the following as element, compound or mixture (Hint: 3 of each) 1. Sand 2. Carbon Dioxide 3. Tea 4. Co 5. CO 6. Gatorade 7. Gold 8. Water 9. Nitrogen

Identify the following as element, compound or mixture (Hint: 3 of each) 1. Sand 2. Carbon Dioxide 3. Tea 4. Co 5. CO 6. Gatorade 7. Gold 8. Water 9. Nitrogen

Give an example of 2 each: element, compound and mixture

Chocolate chip cookies = heterogeneous mixture Chocolate milk = homogeneous mixture 1. Pizza = 2. Brass = 3. Explain the difference

Chocolate chip cookies = heterogeneous mixture Chocolate milk = homogeneous mixture 1. Pizza = Hetero 2. Brass = Homo 3. Explain the difference Homo = same (Mixture is same – you can’t see different parts) Hetero = different - you can see different parts (look for 2 states of matter – solid and liquid)

Identify the following as properties of solids, liquids or gases (may be more than one) Has definite volume Flows and takes the shape of its container Compressible Occupies its entire container

Identify the following as properties of solids, liquids or gases (may be more than one) Has definite volume Flows and takes the shape of its container Compressible Occupies its entire container

Identify the following as chemical or physical properties A sheet of aluminum can be formed into a bowl The melting point of ice is 0 degrees Celcius Sodium is highly reactive with water

Identify the following as chemical or physical properties A sheet of aluminum can be formed into a bowl The melting point of ice is 0 degrees Celcius Sodium is highly reactive with water

Identify the following as chemical or physical properties A sheet of aluminum can be formed into a bowl The melting point of ice is 0 degrees Celcius Sodium is highly reactive with water

Identify the following as extensive or intensive properties (Hint: 2 Extensive) 1. Boiling point 2. Length 3. Density 4. Color 5. Melting point 6. Mass

Identify the following as extensive or intensive properties (Hint: 3 of each) 1. Boiling point 2. Length 3. Density 4. Color 5. Melting point 6. Mass

The 4 signs of a chemical change are: 1. Color change 2. Temperature change 3. Gas released 4. Precipitate formed

Give an example of when color change is a physical property not a chemical property.

Painting a wall – no change in composition

Give an example of when temperature change is a physical property not a chemical property.

Heating water up – still H 2 O just hotter.

Give an example of when gas being released is a physical property not a chemical property.

Give an example of when gas being released is a physical property not a chemical property. Evaporation – still same composition just different state of matter

Identify the following as chemical or physical changes Dissolving of salt in water Cutting an apple Digesting an apple Photosynthesis Fading of Dye

Identify the following as chemical or physical changes Dissolving of salt in water Cutting an apple Digesting an apple Photosynthesis Fading of Dye

Identify the following as extensive or intensive properties 1. Color 2. Boiling Point 3. Luster Identify the following as heterogeneous or homogeneous mixtures 1. Gasoline 2. Dissolved Sugar Water 3. Alloy

State the law of conservation of mass in your own words g of Sodium react completely with 80 grams of Chlorine to form how many grams of table salt? grams of Hydrogen and 13 grams of Oxygen react to form 30 grams of Water. Some Oxygen was not reacted how many grams of Oxygen were left over?

Problem Solving Solving Numeric Problems (3 Steps) Analyze Calculate Evaluate Solving Nonnumeric Problems (2 Steps) Analyze Solve

Problem Solving Example Numeric Problem You want to buy a new cell phone that cost $200. You make $10/hr at your job. How many hours do you have to work in order to buy the phone?

Problem Solving Example Numeric Problem You want to buy a new cell phone that cost $200. You make $10/hr at your job. How many hours do you have to work in order to buy the phone? Analyze Known Wage = $10 / 1 hour Money needed = $200 Unknown Time (amount of hours to work)

Problem Solving Example Numeric Problem You want to buy a new cell phone that cost $200. You make $10/hr at your job. How many hours do you have to work in order to buy the phone? Calculate 200 dollars X __1 hour = 20 hours 1 10 dollars