1 2 Introduction to Chemistry Notes Chemistry and

1. 2 – Introduction to Chemistry Notes

Chemistry and Matter • A. Chemistry – the Central Science • Definition of chemistry: study of matter and the changes it undergoes; • Define matter: Matter is anything that takes up space and has mass; most things are a form of matter; • What is a chemical? any substance that has a definite composition

Chemistry and Matter • 1. Mass vs. weight • - mass is a measure of the amount of matter an object has; doesn’t change; measured with a balance which has 2 pans; weights put on one pan and object put on the other; pivot point in the middle; 2 pans serve to counteract the effect of gravity b/c gravity pulls equally on both pans;

Chemistry and Matter • - weight is a measure of the amount of matter and the effect of gravity; does change depending on the gravitational pull; measured with a scale which has only one pan; gravity acts on the one pan and it alone; Moon’s gravity is 1/6 of the Earth – a 120 lb person on Earth would only weigh 20 lbs on the Moon, but his/her mass would remain the same;

Chemistry and Matter • 2. Macroscopic, microscopic and submicroscopic • macroscopic is what we see with the naked eye; • microscopic is what cannot be seen with the naked eye; fortunately, chemical reactions can be observed at the macroscopic level; • submicroscopic is too small to be seen with an ordinary light microscope

C. Five traditional branches of chemistry • • • organic – study of carbon; inorganic – study of elements other than carbon physical – behavior and changes of matter related to energy changes analytical – composition of substances biochemistry – processes of living things;

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