Name: Unit 1-Additional Practice Period: 1. Powdered iron is magnetic, but powdered sulfur is not. What occurs when they form a mixture in a beaker at room temperature? A) The iron retains its magnetic properties. B) The iron loses its metallic properties. C) The sulfur gains magnetic properties. D) The sulfur gains metallic properties. 5. Which diagram represents a physical change, only? A) 2. Which substance can not be broken down by a chemical change? A) ammonia B) arsenic C) ethane D) propanal B) 3. Compared to the physical and of the compound, the compound has A) different physical properties and different B) different physical properties and the same C) the same physical properties and different D) the same physical properties and the same C) D) 4. Which species represents a chemical compound? A) N2 B) NH4 + C) Na D) NaHCO3 6. Which type of matter is composed of two or more elements that are chemically combined in a fixed proportion? A) solution B) compound C) homogeneous mixture D) heterogeneous mixture 7. Which compounds are electrolytes? A) C2H5OH and H2SO4 B) C2H5OH and CH4 C) KOH and H2SO4 D) KOH and CH4
8. Which diagram represents a mixture of two different molecular forms of the same element? A) B) 11. A student intended to make a salt solution with a concentration of 10.0 grams of solute per liter of solution. When the student s solution was analyzed, it was found to contain 8.90 grams of solute per liter of solution. What was the percent error in the concentration of the solution? A) 1.10% B) 8.90% C) 11.0% D) 18.9% C) D) 12. A student measures the mass and volume of a piece of aluminum. The measurements are 25.6 grams and 9.1 cubic centimeters. The. student calculates the density of the aluminum. What is the percent error of the student s calculated density of aluminum? A) 1% B) 2% C) 3% D) 4% 9. Which particle model diagram represents only one compound composed of elements X and Z? 13. The diagram below represents a Celsius thermometer recording a certain temperature. A) B) C) D) 10. A student determined in the laboratory that the percent by mass of water in CuSO 5H2O is 40.0%. If the accepted value is 36%, what is the percent of error? A) 0.11% B) 1.1% C) 11% D) 4.0% What is the correct reading of the thermometer? A) 5 C B) 4.3 C C) 0.3 C D) 4 C
14. Which measurement contains a total of three significant figures? A) 0.12 B) 012 C) 120 D) 120. 15. Which element has the greatest density at STP? A) scandium B) selenium C) silicon D) sodium 16. Which substance can be decomposed by a chemical change? A) sodium B) argon C) sulfur D) ammonia 21. Bronze contains 90 to 95 percent copper and 5 to 10 percent tin. Because these percentages can vary, bronze is classified as A) a compound B) an element C) a mixture D) a substance 22. A mixture of sand and table salt can be separated by filtration because the substances in the mixture differ in A) boiling point B) density at STP C) freezing point D) solubility in water 17. Which balanced equation represents a chemical change? A) H2O( ) + energy H2O(g) B) 2H2O( ) + energy 2H2(g) + O2(g) C) H2O( ) H2O(s) + energy D) H2O(g) H2O( ) + energy 23. Which sample of matter can be separated into different substances by physical means? A) LiCl(aq) B) LiCl(s) C) NH3(g) D) NH3( ) 18. Which equation illustrates conservation of mass? A) H2 + Cl2 HCl B) H2 + Cl2 2 HCl C) H2 + O2 H2O D) H2 + O2 2 H2O 19. Two grams of potassium chloride are completely dissolved in a sample of water in a beaker. This solution is classified as A) an element B) a compound C) a homogeneous mixture D) a heterogeneous mixture 20. Which formula represents a mixture? A) C6H12O6( ) B) C6H12O6(s) C) LiCl(aq) D) LiCl(s)
24. Base your answer to the following question on the information below. The active ingredient in the pain reliever aspirin is acetylsalicylic acid. This compound can be produced by reacting salicylic acid with acetic acid. The label of one aspirin bottle indicates that the accepted mass of acetylsalicylic acid in each tablet is 325 milligrams. In a laboratory, an aspirin tablet is crushed and mixed with water to dissolve all of the acetylsalicylic acid. The measured ph of the resulting solution is 3.0. The mass of acetylsalicylic acid in one aspirin tablet is determined to be 320. milligrams. Show a numerical setup for calculating the percent error for the mass of acetylsalicylic acid in this aspirin tablet. Base your answers to questions 25 and 26 on the information below. Archimedes (287 212 BC), a Greek inventor and mathematician, made several discoveries important to science today. According to legend, Hiero, the king of Syracuse, commanded Archimedes to find out if the royal crown was made of gold, only. The king suspected that the crown consisted of a mixture of gold, tin and copper. Archimedes measured the mass of the crown and the total amount of water displaced by the crown when it was completely submerged. He repeated the procedure using individual samples, one of gold, one of tin, and one of copper. Archimedes was able to determine that the crown was not made entirely of gold without damaging it. 25. Determine the volume of a 75-gram sample of gold at STP. 26. Identify one physical property that Archimedes used in his comparison of the metal samples. 27. A student used a balance and a graduated cylinder to collect the following data: a Calculate the density of the element. Show your work. Include the appropriate number of significant figures and proper units. b If the accepted value is 6.93 grams per milliliter, calculate the percent error. c What error is introduced if the volume of the sample is determined first?
28. Base your answer to the following question on Heat is added to a sample of liquid water, starting at 80.ºC, until the entire sample is a gas at 120.ºC. This process, occurring at standard pressure, is represented by the balanced equation below. H2O( ) + heat H2O(g) In the box below, using the key, draw a particle diagram to represent at least five molecules of the product of this physical change at 120. C.
Answer Key Unit 1-Additional Practice 1. A 2. B 3. A 4. D 5. A 6. B 7. C 8. A 9. C 10. C 11. C 12. D 13. B 14. D 15. B 16. D 17. B 18. B 19. C 20. C 21. C 22. D 23. A 24. 27. a) Examples: or, or, and accept only to the nearest tenth with a range from 6.7-6.9 Proper Units: g/ml or grams per milliliter b) Range of 1.8-2.0% c) The density would increase because the sample was wet when weighed 28. Five water molecules are drawn and all of the particles drawn represent the gas phase. 25. 3.9 cm 3 26. Examples: density mass volume