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Unit One: Review. Chemistry II. What is Chemistry?. Chemistry: The study of matter, its structure, properties, and composition, and the changes that matter undergoes a. Matter – has mass and takes up space. II. Graph – a visual display of information. 3 types : line, bar, and pie graph
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Unit One: Review Chemistry II
What is Chemistry? • Chemistry: The study of matter, its structure, properties, and composition, and the changes that matter undergoes a. Matter – has mass and takes up space
II. Graph – a visual display of information 3 types : line, bar, and pie graph A. Line Graph – shows how information changes over time, or to show continuous data
Example: Day of the Week Temperature Sunday 81 Monday 86 Tuesday 82 Wednesday 79 Thursday 76 Friday 80 Saturday 74
B. Bar Graph – Compares collected information in columns (non-continuous data)
III. SI System – International System of Standards A. Base units: Mass – kg (only one with a prefix) Length – m Time – s B. Derived units – combinations of base units by multiplication or division ex: speed – m/s force = N = kg*m/s2
C. Prefixes – - used to express big or small extremes Micro µ (1x106µm/m) Milli m (1x103mm/m) Centi c (1x102cm/m) Deci d (1x101dm/m) ------ DekadK (1x10-1dKm/m) Hecto h (1x10-2hm/m) Kilo k (1x10-3km/m) Mega M (1x10-6Mm/m)
III. Density • Density – amount of matter present in a given volume of substance
Practice: Suppose a student finds that 23.50 mL of a certain liquid weighs 35.062g. What is the density of this liquid? Density = mass = 35.063g = 1.492 g/mL volume 23.50 mL
B. Density Determination 1. Submerge object in water and measure the volume of water it displaced Example: measuring a person’s % body fat
C. Uses 1. Identification of substances
2. Specific Gravity – the ratio of the density of a given liquid to the density of water at 4 degrees C - because it is a ratio of densities, it has no units