Midterm Review 1 CR - Math and Matter

Transcription

1 Midterm Review 1 CR - Math and Matter Name Base your answers to questions 1 and 2 on the information below and on your knowledge of chemistry. A few pieces of dry ice,, at are placed in a flask that contains air at. The flask is sealed by placing an uninflated balloon over the mouth of the flask. As the balloon inflates, the dry ice disappears and no liquid is observed in the flask. 1. Write the name of the process that occurs as the dry ice undergoes a phase change in the flask. 2. State the direction of heat flow that occurs between the dry ice and the air in the flask. 3. Base your answer to the following question on the information below and on your knowledge of chemistry. Paintball is a popular recreational activity that uses a metal tank of compressed carbon dioxide or nitrogen to launch small capsules of paint. A typical tank has a volume of 508 cubic centimeters. A 340.-gram sample of carbon dioxide is added to the tank before it is used for paintball. At 20. C, this tank contains both CO2(g) and CO2( ). After a paintball game, the tank contains only CO2(g). In the box above, use the key to draw a particle diagram to represent the two phases of CO2 in a newly filled tank. Your response must include at least six molecules of CO2 in each phase.

2 Base your answers to questions 4 through 6 on the information below. A student prepared two mixtures, each in a labeled beaker. Enough water at 20. C was used to make 100 milliliters of each mixture. 4. Describe a procedure to physically remove the water from mixture Determine the volume of the Fe filings used to produce mixture Classify each mixture using the term homogeneous or the term heterogeneous. Base your answers to questions 7 and 8 on the information below. A method used by ancient Egyptians to obtain copper metal from copper(i) sulfide ore was heating the ore in the presence of air. Later, copper was mixed with tin to produce a useful alloy called bronze. 7. A gram sample of bronze was 10.3% tin by mass. Determine the total mass of tin in the sample. 8. Calculate the density of a -gram sample of bronze that has a volume of cubic centimeters. Your response must include a correct numerical setup and the calculated result.

3 9. Based on data collected during a laboratory investigation, a student determined an experimental value of 322 joules per gram for the heat of fusion of H2O. Calculate the student's percent error. Your response must include a correct numerical setup and the calculated result. 10. Describe one appropriate laboratory test that can be used to determine the malleability of a solid sample of an element at room temperature. 11. Base your answer to the following question on the information below. A lightbulb contains argon gas at a temperature of and at a pressure of kilopascals. The lightbulb is switched on, and after minutes its temperature is. What Celsius temperature is equal to 418 K?

4 Base your answers to questions 12 and 13 on the information below. Archimedes ( 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. 12. Determine the volume of a 75-gram sample of gold at STP. 13. Identify one physical property that Archimedes used in his comparison of the metal samples. 14. Base your answer to the following question on Using a triple beam balance and a graduated cylinder, a student collected data on a sample of an element: Mass of sample Volume of water Volume of water and sample 10.9 g 30.0 ml 34.0 ml a) Calculate the density of the sample. Show all work and use significant figures and units. b) Based on Reference Table S, what element might the sample be? Base your answers to questions 15 through 17 on the pictures below: 15. Contrast sample A and sample B, in terms of compounds and mixtures. Include both sample A and sample B in your answer.

5 16. Explain, in terms of the composition, why sample A represents a pure substance. 17. Explain how the average kinetic energy of sample B can be equal to the average kinetic energy of sample C. Base your answers to questions 18 through 20 on the diagram below concerning the classification of matter. 18. Explain, in terms of particle arrangement, why NaCl(aq) is a homogeneous mixture. 19. What type of substance is represented by Z? 20. What type of mixture is represented by X?