1. Mr. Ramos

2.  Chemistry is the study of matter, and matter is the stuff things are made of.  Matter is anything that takes up space and has mass.  All matter is composed of small particles known as atoms.  Chemistry is known as the central science

3.  Chemistry has been divided into 5 branches ◦ Organic Chemistry is the study of all substances that contain carbon. ◦ Inorganic Chemistry is the study of substances that do not contain carbon. ◦ Analytical Chemistry is concerned with error and precision, separation, identification, and quantification of substances. ◦ Physical Chemistry is concerned with theories & experiments that describe the behavior of chemicals. In other words, it is the physics of chemicals and reactions. ◦ Biochemistry is the study of the chemistry of living organisms.

4.  SI Units, also known as System of International Units, are used by scientists all over the words to make conversions easier.  In chemistry we use grams for mass instead of kilograms since we deal with very small quantities.

5.  There is error associated with every measurement.  Accuracy is a measure of how close a measurement comes to the actual or true value. Keep in mind there is no way to measure the “true” value of anything.  Precision is a measure of how close a series of measurements are to one another; you may be precise but not accurate.

6.  Suppose you want to measure the boiling point of water with a thermometer and the thermometer reads 99.1°C, but you know that water’s boiling point is actually 100°C.  100°C, is the accepted value. An accepted value is the correct value based on reliable references. This is also known as the theoretical value.  99.1°C is the experimental value. This is the value measured in the lab.  Error = experimental value – accepted value

8.  Suppose you estimate a temperature that lies between 23°C and 24°C to be 24.3°C. This estimated number has 3 digits.  The first two digits (2 & 4) are known with certainty, but the rightmost digit has been estimated and involves some uncertainty.  Significant figures in a measurement include all of the digits that are known, plus a last digit that is estimated.

9.  1. Every nonzero digit is significant ◦ 24.7, 0.743, and 714 each have 3 sig figs  2. Zeros between nonzero digits are significant ◦ 7003, 40.79, and 1.503 each have 4 sig figs  3. Leftmost zeros appearing in front of nonzero digits are not significant ◦ 0.0071, 0.42, and 0.000099 all have 2 sig figs

10.  4. Zeros at the end of a number and to the right of a decimal are always significant ◦ 43.00, 1.010, and 9.000 each have 4 sig figs  5. Zeros at the rightmost end of a measurement that does not bare a decimal point are not significant; however they are ambiguous. ◦ 300, 7000, and 10,000 all have 1 sig fig ◦ If written in scientific notation, more than 1 sig fig may apply. These numbers are ambiguous  6. Unlimited sig figs exist in two situations: ◦ Counting: 23 people in the class (this is an exact measurement) ◦ Exactly defined quantities: 1hour = 60 minutes

11.  5.12500  0.0204  5.20x10 13  5.0x10 -3  1 ft = 12 inches  300  0.600  0.3056  0.002

12.  Scientific notation is a way of writing numbers that are too big or too small to be conveniently written in decimal form.  Imagine having to write and read a number this this big: 60221.000  To write a number in scientific notation, place a decimal between the first two digits of that number. The first digit cannot be a zero. Then, place a x 10 n.  60221.000 becomes 6.0221 x 10 4

13.  89600000  0.0056  90.80  70000  0.6080  5.26  23.5  34.65 x 10 2  0.065 x 10 3