1. Classify each of the following as a pure substance or a mixture; if a mixture, indicate whether it is homogeneous or heterogeneous.
- a) Diesel Gasoline (Answer: Mixture, homogeneous)
- b) Seawater (Answer: Mixture, homogeneous)
- c) Beer (Answer: Mixture, heterogeneous)
- d) Salad Dressing (Answer: mixture, heterogeneous)
2. Name the chemical elements represented by the following symbols.
- a) Ni (Answer: Nickel)
- b) Al (Answer: Aluminum)
- c) Sn (Answer: Tin)
- d) Mg (Answer: Magnesium)
- e) F (Answer: Fluorine)
- f) In (Answer: Indium)
- g) Li (Answer: Lithium)
- h) K (Answer: Potassium)
3. Name each of the following elements.
- a) Tl (Answer: Thallium)
- b) Ac (Answer: Actinium)
- c) Se (Answer: Selenium)
- d) Eu (Answer: Europium)
4. A solid white substance A is heated strongly in the absence of air. It decomposes to form a new white substance B and a gas C. The gas has exactly the same properties as the product obtained when carbon is burned in an excess of oxygen.
- What is solid A most likely to be? (Answer: compound)
- What is solid B most likely to be? (Answer: cannot be determined)
- What is gas C most likely to be? (Answer: compound)
5. Read the following description of the element zinc, and indicate which are physical properties and which are chemical properties.
- Zinc is a silver-gray colored metal. (Answer: physical)
- Zinc melts at 420° C. (Answer: physical)
- When zinc granules are added to dilute sulfuric acid, hydrogen is given off and the metal dissolves. (Answer: chemical)
- Zinc has a hardness on the Mohs scale of 2.5. (Answer: physical)
- Zinc has a density of 7.13 g/cm3 at 25°C. (Answer: physical)
- Zinc reacts slowly with oxygen gas at elevated temperatures to form zinc oxide, ZnO. (Answer: chemical)
6. Label each of the following as either a physical process or a chemical process.
- Pulverizing aspirin. (Answer: physical)
- Explosion of nitroglycerin. (Answer: chemical)
- Butter melting when placed in sunlight. (Answer: physical)
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