Chem 1111 Chapter one: Matter-its properties and measurement 1.The scientific method 2.Properties of matter 3.Classification of matter 4.Measurement of matter: SI units 5.Density and Percent Composition: their uses in problem solving 6.Uncertainties in scientific measurements 7.Significant figures 1. THE SCIENTIFIC METHOD Natural laws: are concise s tatements, often in mathematical form, about natural phenomena, We should not think of a natural law as an absolute truth. Future experiments may require us to modify the law. Hypothesis: is a tentative explanation of natural law. Theory: is a model or way of looking at nature that can be used to explain natural laws and make further prediction about natural phenomena. Scientific method: is the combination of observation, experimentation, and the formulation oflaws, hypotheses, and theories. 2. PROPERTIES OF MATTER Matter: is anything that occupies space and displays the properties ofmass and inertia. Composition: refers to the part of components of a sample of matter and their relative proportions. Eg: What is made up of two simpler substances= hydrogen and oxygen, a chemist would say that the composition of water is 11.19% hydrogen and 88.81% oxygen. Properties: are those qualities or attributes that we can use to distinguish one sample of matter from others: two broad categories: physical and chemical. Physical properties and physical changes Physical property: is one that a sample of matter displays without changing its composition/ Physical change: some of the physical properties of the sample may change, but its composition remains unchanged. Eg. when liquid water freezes into solid water (ice).
