Introduction to Chemistry SNC1DE Introduction to Chemistry

What is Chemistry? Chemistry is the study of matter and its composition Discovery of interactions between different types of matter (reactions) Properties of matter can be manipulated for use by man

Properties of Matter Properties of matter are characteristics that help you describe and identify matter Properties can be described or measured Subcategorized into physical and chemical properties

Physical Properties Physical property is a property that you can observe without changing one kind of matter into something new Qualitative observations are based on qualities of the matter Quantitative observations can be measured with a number and unit

Physical Properties Qualitative includes: Physical state Colour Odour Crystal shape Malleability Ductility Hardness Brittleness Quantitative includes: Melting point Boiling point Density Solubility Electrical conductivity Thermal conductivity

Chemical Properties A chemical property is a property that you can observe when one kind of matter is converted into a different kind of matter Example: A chemical property of iron is that is reacts with oxygen to form rust

Chemical Properties Qualitative includes: Reactivity with water Reactivity with air Reactivity with pure oxygen Reactivity with acids Reactivity with pure substances Combustibility Quantitative includes: Toxicity Decomposition

Using Measurements QuantitySI Definition SI Units Equipment used Mass The amount of matter in an object Grams kg, g, mg, ug Balance Length The distance between two points Metres m, cm, mm Ruler Temperature The hotness or coldness of a substance Kelvin (K) Degrees Celsius (oC) Thermometer Volume The amount of space an object occupies Cubic metre (m3) Litre (L) Millilitre (ml) Beaker, graduated cylinder, pipette, calculated Mole The amount of a substance Mole (mol) Calculated Density Mass per unit of volume Kg/m3 Calculated or measured Energy The capacity to do work (to move matter) Joule (J)

Measuring and Calculating Values Significant digits are used for accuracy and precision Accuracy refers to how close a given quantity is to an accepted or expected value Precision refers to the exactness of a measurement

Physical Changes Matter can be classified as either a gas, liquid, or solid Generally, as you add energy, particles move faster and farther apart As you remove energy, particles move closer and become attracted to each other

Chemical Changes Chemical changes are changes that alter the composition of matter Clues include: Change in colour Temperature change Gas forms Precipitate forms Irreversible

Classifying Matter Matter is either a pure substance or mixture Pure substances have a definite composition, has the same response to physical changes Mixtures are a physical combination of two or more kinds of matter

Pure Substances Elements are pure substances that cannot be separated chemically into any simpler substances Compounds are pure substances that result when two or more elements combine chemically into a new substance

Mixtures Heterogeneous mixtures are mixtures that are visibly separate Homogenous mixtures are mixtures that are cannot be separated by eye