CH 1 Mixed Questions Worksheet

Chemistry CH 1 Mixed Questions Worksheet Name ______Period ______Date ______

1. Which of the following are solutions? A) our atmosphere B) Gold powder and silver powder ground together C) piece of 18-karat jewelry made from melting gold and silver metals together D. oil droplets suspended in water 2. Fog is a suspension of tiny droplets of water in air. Is fog a heterogeneous or homogeneous mixture? Explain 3. Which of the following are compounds A) Fe2O3 B) O3 C) Fe D) CO E) C3H8 4. T/F? A compound is a pure substance, but a pure substance need not be a compound. Give examples to prove your answer 5. Molten iron cooling to solid iron is an example of A) sublimation B) condensation C) freezing D) melting 6. T/F? After being heated to above its boiling point, ethanol is no longer ethanol but something else. Explain 7. You are presented with a block made of some pure metal and told the metal is gold, but you have your doubts. Using a thermometer, how can you determine whether the metal is gold? 8. Which of the following represents a chemical transformation? A) 4P + 5O2 = 2P2O5 B) H20(g) = H2O(l) C) 3O2 = 2O3 9. What is anything, is wrong with the chemical reaction Cl2 + Br2 = 2HCl + 2HBr. Explain 10. What is good evidence that a theory is correct? 11. What is the relationship between a theory and a law? 12. Is it possible to have a mixture of a compound? Explain 13. The air you breathe is properly called a solution. Explain 14. What does a chemical formula tell you about a pure substance? 15. What is the name of the process by which matter changes directly from the solid state to the gas state? 16. At normal atmospheric pressure, the freezing point of ethanol is -117.3 C and its boiling point is 78.5 C. What is the melting point of ethanol and what state would it be in at room temperature (20.0C) 17. What is the normal melting and boiling point of water in Celsius and Fahrenheit? 18. Water, H2O is a harmless liquid, but hydrogen peroxide H2O2 is a poison. Explain how this is possible given both compounds are made up of the same elements. 19. Sugar dissolves in water, has the sugar undergone a physical or chemical change? Explain 20. When ethanol burns, it is converted to carbon dioxide and water. Has ethanol undergone a physical or chemical change? 21. Which of the following is a compound: ozone O3, stainless steel, a combination of iron and other metals, sulfuric acid H2SO4, brewed coffee. 22. Which of the following can form a homogeneous mixture (solution) when mixed thoroughly with water: table salt, sand, table sugar, gold? 23. Mixtures can always be separated by physical means. Describe how you would separate the components in a mixture of sand and iron filings, salt water, lemonade made from real lemons. 24. Below are a listed many properties of octane (C8H18). Identify them as chemical or physical properties. A). Is a liquid at room temperature B) Is a volatile liquid (evaporates easily at room temperature) C) Burns to form CO2 and H2O D) Is a colorless liquid E) Is less dense than water F) Is insoluble in water G) Is a poison H) Dissolves grease well I) Has a bad taste and a slight odor J) Freezes below 57 C 25. Which of the following is a homogeneous mixture? A) milk shake B) 14-karat gold (melting gold w/ other metals) C) fog D) blood