Chapter 1: Introduction to Chemistry

What is chemistry?

Study of stuffStudy of the composition of substances and the changes they undergo

Chemists:

Solve problems dealing w/ the ingredients the world is made of Looks at how it behaves and how it is put together

Research Types:

Pure Research- seeks to gain knowledge for the sake of knowledge itselfApplied Research- research undertaken to solve a specific problem

Scientific Method

Logical approach to solving problems dealing with the “stuff” the world is made ofUses evidence

Steps to the Scientific Method

1. Ask a question/ ID the problem

2. Observe and infer3. Hypothesis- proposition based

on certain assumptions (can be evaluated scientifically), educated guess

4. Experiment

Control/constants/variable-Independent Variable-variable

that you change

-Dependent variable- variable that changes due to the independent variable changing

4. (cont)

Ex. Pressure on a balloon-Increase pressure decreases volume-Independent-pressure, dependent- volume

4. (cont)

Collect data-Qualitative Data- describes a property w/out measurements, uses senses (ex. Color)-Quantitative data – data collected using measurements (ex. Volume)

5. Conclusion

Refers to hypothesisSupport with evidence found in experimentUse Models (develop in mind or physically to help deal with abstract ideas or objects that are too big, too small or too complicated)

Ingredients of Chemistry:

1. Matter

Stuff, everythingHas the property of inertiaTakes up space, has mass

a. Inertia

Resistance to change in motion or resistance to change in direction or rate

b. Mass

Amount of matter in an objectMeasure of the inertiaDoes NOT change from place to placeMeasure with a balance

c. Weight

Measure of the force of gravity between 2 objectsWeight= mass X gravityChanges with locationMeasure with scale

2. Energy

Property possessed by matter, ability to do workWe are interested in the energy changes that take place

Types of Energy

Potential- energy due to the objects position, also stored energy (ex. Battery- chemical potential energy)Kinetic- energy of motionRadiant- energy that goes in all directions (light, x-rays, UV), transferred by electromagnetic wavesOther- heat, sound, nuclear, electric

Rules Chemists Follow:

Theory

-statement that gives a tentative explanation based on supported hypotheses

Ex. Atomic Theory

Law

-describes something that is known to happen without error, but doesn’t explain how it happens

Ex. Laws of Gravity, Laws of Motion

Law of Conservation of Mass

Total amount of matter in the universe remains constantMatter can’t be created nor destroyedTotal amount b/4 reaction= total amount after reaction

Law of Conservation of Energy

Energy can’t be created nor destroyedTotal amount remains constantCan transform into different types of energy

Ex. Match: potential chemical energy into heat, light, sound, kinetic

Chapter Practice

http://www2.waterforduhs.k12.wi.us/staffweb/smith/Nancy/chemistry/chemistry%20homework.htm