Key Concepts: CP Chemistry Study Guide Test 1 (Ch 1 and 2) What is alchemy and how did it influence chemistry? What are the steps to the scientific method? Why are communication and collaboration important in chemistry and other sciences? How can properties used to describe matter be classified? Why do all samples of the same substance have the same intensive properties? What are the three states of matter? How can physical changes be classified? How can mixtures be classified? (two types) How can mixtures be separated? Define density- what is the relationship between mass and volume? What is the density of water? Key Terms: Matter Chemistry Scientific method Observation Hypothesis Experiment Theory Scientific Law Mass Volume Density Extensive property Intensive property Substance Physical property Solid Liquid Gas Vapor Physical change Mixture Heterogeneous mixture Homogeneous mixture Solution Phase Filtration Distillation
Practice Problems: 1. The following is a list of observations from everyday experiences: - Hummingbirds have long beaks - Moisture forms on the outside of a cold glass - Ice cubes float - Oil and water don t mix - There are fewer fish in the creek this year a. Propose one hypothesis for each observation b. Select one hypothesis and describe an experiment that you could do to test it. Answers will vary- use steps to the scientific method 2. Discuss the statement No theory is written in stone. A theory can be disproven 3. Which of the following is not a physical change? a. Dissolving sugar in water b. Burning gasoline in an engine c. Evaporating sea water to obtain salt d. Slicing a piece of bread 4. Which of the following is not a property of a gas? a. Has a definite shape b. Has an indefinite volume c. Assumes the shape of the container d. Is easily compressed 5. Which of the following is in a different physical state at room temperature than the other three states? a. Salt b. Sugar c. Flour d. Water 6. Complete the following table. Physical state Definite shape? Definite volume? Easily compressed? Gas no No Yes Liquid No Yes No Solid yes yes no
7. How might you separate a mixture of water and salt? Let the water evaporate(or boil it away) and the salt will crystallize behind. 8. What is a homogenous mixture? Aka a solution; all one phase, the same throughout 9. Which of the following mixtures are homogenous? Which are heterogenous? a. Gasoline homogenous b. Chunky peanut butter heterogenous c. Oil and vinegar salad dressing heterogenous 10. Which of the following are substances? Which of the following are mixtures? a. Ethanol substance b. Motor oil mixture c. Vinegar substance or mixture d. Neon substance 11. What elements make up ammonia, chemical formula, NH3? Nitrogen and hydrogen 12. Name the elements represented by the following chemical symbols. a. Pb lead b. K potassium c. Au gold d. Fe iron 13. Classify the following as elements, compounds, or mixtures. a. Table salt compound b. Water compound c. Iron element d. Stainless steel mixture 14. Write the chemical symbol for each of the following elements. a. Tin Sn b. Sodium Na c. Silver Ag d. Carbon C 15. Which of the following is not an element? a. Copper b. Sulfur c. Sucrose d. Helium
16. Which of the following is a chemical change? a. Gasoline boils b. Oxygen is added to gasoline c. Gasoline burns d. Gasoline is poured into a tank 17. Classify each of the following as physical or chemical. a. A puddle is dried by the sun physical b. A dark cloth is faded by sunlight chemical c. Bread is toasted chemical d. Soap is mixed with water physical 18. Carbon dioxide plus water makes carbonic acid. a. Name the reactant(s) of this reaction carbon dioxide and water b. Name the product(s) of this reaction carbonic acid 19. If 44 grams of carbon dioxide react completely with 18 grams of water, what is the mass of carbonic acid formed? 44 g + 18g = 62g 20. In an engine, octane combines with oxygen to form carbon dioxide and water. If 22.8 grams of octane combine completely with 80 grams of oxygen to form 70.4 grams of carbon dioxide, what mass of water is formed? Octane + Oxygen Carbon dioxide + water 22.8g 80g 70.4g?g 102.8g 70.4 g +? 102.8g 70.4g = 32.4 g 21. What is the name of the chemical law that problems 19 and 20 are based? Law of conservation of mass 22. Pure gold has a density of 19.32 g/cm 3. How large would a piece of gold be if it had a mass of 318.97 g? D = 19.32g/cm 3 V = m/d = 318.97g 19.32g/cm 3 M = 318.97g v = 16.5cm 3 V =?cm 3
23. The density of lead is 11.342 g/ml. What would be the volume of a 200.0 g sample of this metal? D = 11.342g/mL V =? M = 200.0g V = m/d = 200.0g 11.342g/mL v = 17.6mL 24. The mass of a toy spoon is 7.5 grams, and its volume is 3.2 ml. What is the density of the toy spoon? M = 7.5g V = 3.2mL D =? d = m/v = 7.5g 3.2mL d = 2.3g/mL