Chapter 1 Chemistry: Matter Classification of Matter Physical & Chemical Changes/Properties Elements, Compounds, and Mixtures Separation Techniques Solid, Liquids, Gases
Branches of Chemistry organic chemistry—the study of carbon-containing compounds inorganic chemistry—the study of non-organic substances physical chemistry—the study of properties of matter, changes that occur in matter, and the relationships between matter and energy analytical chemistry—the identification of the composition of materials biochemistry—the study of the chemistry of living things theoretical chemistry—the use of mathematics and computers to design and predict the properties of new compounds
PHYSICAL PROPERTIES OF MATTER Can be broken into two types Extensive properties – are dependent on the amount of substance present. Intensive properties – are independent of the amount of substance
OF THE PHYSICAL PROPERTIES OF MY PEN, WHICH ARE EXTENSIVE AND WHICH ARE INTENSIVE?
CHEMICAL PROPERTIES OF MATTER Ability of a substance to combine with or change into one or more other substances
Properties of Matter Property – a characteristic Chemical properties: characteristics of a substance’s “ability” to change into a different substance. Brainstorm a list of chemical properties as a group. Physical properties: characteristics that can be observed or measured without changing the identity of the substance. Brainstorm a list of physical properties as a group. Hint: Think of gasoline!
DECIDE WHICH ARE CHEMICAL OR PHYSICAL PROPERTIES Physical Properties? Chemical Properties?
OBSERVING PROPERTIES OF MATTER Depends on conditions of matter. So, you should always state the conditions. Water observations at 23°C versus 120°C or -12°C
Density of Water: 1.00 g/mL Density of Ice: 0.92 g/mL Which one floats? Why?
Predict the correct “floating order” of the substances as they would appear in the “Density Column”. SubstanceDensity g/cm 3 Copper8.8 Corn oil0.925 Corn syrup1.38 Glycerin1.26 Mercury13.6 Plastic0.93 Rubber1.34 Tar1.02 Water1.00 Wood0.7
Is the bar really gold or fool’s gold? Find the density of the bar if the mass is 1891.4 g and the dimensions are 3.5 cm by 3.5 cm by 8.0 cm. Gold has a density of 19.3 g/cm 3 V = L x W x H D = m/v 1891.4 g / 98 cm 3 = 19.3 g/cm 3 Yes it’s gold! d m v
Is the “Silver Surfer” really made of silver? We obtained a sample with a mass of 262.5 g. Platinum 21.5 g/cm 3 Silver 10.5 g/cm 3 Tin 7.3 g/cm 3 Find the volume by water displacement. d m v d = m/v = 262.5 g / 25 cm 3 = 10.5 g/cm 3 It is Silver!
Boats are made so that they have a lower density than water.
Changes of Matter Chemical Changes: A change that does produce a new substance. Usually not reversible. Ex: Iron rusts forming iron oxide. Physical Changes: A change that does not produce a new substance. Usually reversible. Ex: Ice melts into water.
How do you know a chemical change has occurred? Evidence of a Chemical Change: 1. Energy (Heat): absorbed energy (endothermic) released energy (exothermic) 2. Gas is produced (bubbles) 3. Solid (precipitate) forms 4. Odor or color change occurs Physical change begins in the mouth
Identify the following as a physical property, a chemical property, a physical change, or a chemical change. Ice melting Tarnishing in moist air Silver in color Conducts electricity Ability to explode Recycled aluminum can Ability to react with acid Burned the popcorn Physical change Chemical change Physical property Chemical property Physical change Chemical property Chemical change