CREATING COMPOUNDS: INVESTIGATING CHEMICAL CHANGES
Chlorophyll a is one of the green pigments found in plants. Chlorophyll a has the molecular formula C 55 H 72 MgN 4 O 5 . How many atoms are in this molecule?
137
Which of the following is not a phase change?
Hydrogen and Oxygen gas combining to form water vapor
Phase Change
A change from one state of matter to another
Physical Change
A change in shape, size, or physical characteristics but remaining same substance
Law of Constant Composition
A pure compound consists of exactly the same elements in the exact same ratios by mass
Fill in the physical properties of oxygen cited in the text:
Color: Colorless Solubility in Water: Slight Freezing Point: -128 Boiling Point: -183
The process of passing electricity through water to chemically separate it into hydrogen and oxygen is called what?
Electrolysis
Classify each of the following as a physical change or a chemical change.
Grinding Glass: Physical Rusting of Iron: Chemical Burning a Candle: Chemical Sanding Wood: Physical
The molecular formula for caffeine is C 8 H 10 N 4 O 2 . Which of the following elements is not found in caffeine?
Helium
Plants make glucose by a chemical process called:
Photosynthesis
Molecule
The smallest unit of a compound
Chemical Change
The starting materials completely lose their properties to form new substances
Iron filings can be separated from a mixture with sulfur by using a magnet.
True
The various components of a mixture do not combine chemically.
True
Unknown compounds can usually be identified based solely on their physical properties.
True
Classify each of the following as a physical change or a chemical change.
Melting Ice: Physical Souring of Milk: Chemical Digesting Food: Chemical Evaporating Water: Physical