Quarter 1 Unit 2 Review Sheets Elements, Compounds, & Mixtures 1. Describe each substance below as either a pure substance or a mixture

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1 Name_ Quarter 1 Unit 2 Review Sheets Elements, Compounds, & Mixtures 1. Describe each substance below as either a pure substance or a mixture H 2 O Pure (compound) Na Pure (element) C 6 H 12 O 6 Pure (compound) NaCl and H 2 O (salt water) Mixture ir (N 2 and O 2 ) Mixture 2. Match each definition below with the correct term: Element Compound Homogenous Mixture Heterogeneous Mixture Element substance made of only one kind of atom Homog. Mixture substance with 2 or more elements and/or compounds that are in the same place and the same throughout Heterog. Mixture substance with 2 or more elements and/or compounds that are in the same place but are different throughout Compound substance with 2 or more different atoms chemically combined 3. Circle all that apply for each of the following statements: E C M Impossible to separate E C M Usually easy to separate E C M Usually difficult to separate E C M Can only be separated by chemical means E C M Can be separated by physical means E C M Pure substances

2 Name_ 4. What does each diagram below represent?. Element. Compound C. Mixture of elements D. Mixture of compounds E. Mixture of elements and compounds E C Physical & Chemical Properties and Changes 5. Match each separation technique listed below with the correct circumstance: ) Use a chemical reaction ) Filtering C) Use a magnet D) oiling/evaporating C Iron from a mixture of iron and sand Iron from the compound iron sulfide (FeS) D Salt from salt water Sand from a mixture of sand and water 6. Describe each below as either ) physical change ) chemical change Splitting wood Cooking an egg Rusting a nail Digesting food Ripping paper oiling water Freezing water Exploding dynamite cid eating away at a piece of metal

3 Name_ Thermodynamics 7. What is the difference between heat and temperature? Heat = Heat is a measure of the total energy (depends on temperature, mass, and specific heat capacity) Temperature = Temperature is a measure of the average kinetic energy of the atoms in a sample (how fast the particles move. 8. How does a mercury thermometer work at a molecular level? Thermometer is stuck in a sample. The atoms of the sample collide with the atoms of mercury in the thermometer tube and causes them to vibrate more or less depending on the temperature (KE) of the sample. If the temp is hot, the atoms vibrate more, causing the mercury to expand up the tube. If the temp is cold, the atoms vibrate less, causing the mercury to shrink down the tube. 9. Examine the two beakers below: 75 o C eaker oth beakers are filled with water. eaker a. Which beaker has a higher temperature? EXPLIN WHY! oth are at the same temp. oth at 75 o C b. Which beaker has more heat? EXPLIN WHY! eaker has more heat. oth at same temperature, both same stuff (water) but has more mass so it has more heat. 10. What is a calorie? Energy needed to raise 1 g of water by 1 o C

4 Name_ 11. Examine the two beakers below: 80 o C 60 o C 20 o C 20 o C 50 g H 2 O 250 g H 2 O eaker eaker was filled with 50 grams of water at 20 o C and heated until it reached 80 o C. eaker was filled with 250 grams of water at 20 o C and heated until it reached 60 o C. a. Which beaker reached a higher temperature? eaker b. How much heat did it require to heat: eaker eaker : eaker? : Q = mc (T f - T i ) = (50 g)(1 cal/g o C)(80-20 o C) = 3000 cal : Q = mc (T f - T i ) = (250 g)(1 cal/g o C)(60-20 o C) = 10,000 cal 12. What is specific heat capacity? What is the specific heat capacity of water? How much energy is needed to raise 1 g of a substance 1 o C 1 cal/g o C 13. What three things does the total heat of a system depend on? Mass, specific heat capacity, temperature For questions 14-18, use the equation Q = mc(t f T i ) OR Q = mc T 14. How much heat does it take to raise the temperature of a 250 gram bar of iron (C iron = cal/g o C) from 20 o C to 1000 o C? Q = mc (T f - T i ) = (250 g)(0.108 cal/g o C)( o C) = 26,460 cal 15. What is the final temperature when 2500 calories is applied to a 400 gram block of aluminum (C l = cal/g o C) at 25 o C? Q = mc (T f - T i ) 2500 cal =(400 g)(0.215 cal/g o C)(T f -25 o C) T f = 54 o C

5 Name_ 16. How much water could be heated from 22 o C to 60 o C if 10,000 calories are applied (c water = 1 cal/g o C)? Q = mc (T f - T i ) 10,000 cal = (m)(1 cal/g o C)(60-22 o C) m = 263 g 17. What is the temperature change if 2500 calories is applied to a 250 gram block of copper? c Cu = cal/g o C Q = mc (T f - T i ) 2500 cal = (250 g)(0.092 cal/g o C)(T f - T i ) (T f - T i ) = 109 o C 18. What is the specific heat of a substance if 600 calories makes the temperature of 30 grams of the substance change from 20 o C to 27 o C? Q = mc (T f - T i ) 600 cal = (30 g)(c)(27 20 o C) c = 2.86 cal/g o C For questions use the equation: mc(t f T i ) = - mc(t f T i ) 19. What is the final temperature when a 250 gram lump of aluminum (C l = cal/g o C) at 75 o C is dropped into a beaker of 50 grams of water (c wateer = 1 cal/g o C) at 22 o C? mc(t f T i ) = - mc(t f T i ) (250 g)(0.215 cal/g o C)(T f 75) = - (50 g)(1 cal/g o C)(T f 22) T f = 49.5 o C 20. What is the specific heat of a substance if 75 grams of it at 100 o C is dropped into 25 grams of water (c wateer = 1 cal/g o C) at 20 o C and the final temperature of the system is 28 o C? (75 g)(c)( o C ) = - (25 g)(1 cal/g o C)(28 20) c = cal/g o C ased upon the following graph, answer the following questions: a. Which substance, or, has the higher boiling point? b. Which substance, or, has the lower freezing point? c. Circle the point on the graph where one substance is boiling while the other substance is heating up as a liquid T

6 Name_ For question 22, use the equation: Q = ml 22. The heat of fusion of a substance is 40 cal/gram. How much energy is needed to melt 50 grams of the substance? Q = ml Q = (50g)(40 cal/g) = 2000 cal 23. Match each definition to the correct term: = Conduction = Convection C= Radiation C Heat transfer through pure energy Heat transfer through a movement of a fluid such as air or water Heat transfer through direct contact List each below as either = Conduction = Convection C= Radiation You cool off at the beach with a fan C You get a sunburn The sand at the beach feels really hot on your feet 24. For the three states of matter, match each phase with the correct description: = solid = liquid C = gas C definite volume but no definite shape definite volume and definite shape no definite volume or shape 25. Describe each of the below as either endothermic or exothermic: Exo Heat leaves system Exo urning gasoline Endo Heat enters system Endo Melting ice Endo Heat leaves surroundings Endo Microwaving popcorn Exo Heat enters surroundings Exo Freezing a popsicle Endo System gets hotter Exo Surroundings get hot Exo System gets colder Endo Surroundings get cold

7 Name_ 26. The following information is listed for two different substances: Water: boiling point 100 o C melting point: 0 o C cetone: boiling point 56 o C melting point: -25 o C If samples of each of the materials were distilled at 125 o C and then cooled regularly until they reached -50 o C, draw the expected results on the graph below. Label each line! 150 o C 100 o C 50 o C 0 o C acetone water -50 o C time