CHM 2040 IA Final Review Fall 2017

Transcription

1 CHM 2040 IA Final Review Fall Classify according to composition A). Oxygen gas -Element (Pure substance) B). Sand Heterogeneous mixture C). Bronze Homogenous mixture D). Calcium sulfate crystals -Compound (Pure substance) 2. The process of separating homogenous mixture of liquids A) Filtration B) Decanting C) Distillation 3. Classify based on physical change, Chemical change, physical property and chemical property. (PC, CC, PP and CP rrespectively) A) Smell of camphor - PP B) Burning magnesium ribbon in air -CC C) Sublimation dry ice - PC D) acidity of lemon - CP E) Stretching of copper wire - PC 4. At what temperature Celsius scale and Fahrenheit scale reads the same? A). 0 B). -40 C). 32 D) Round the answer to the correct significant figures and unit cm 8.0cm 7.045cm 7.12cm cm cm A). 7.5*10^2 cm^3 B) cm C). 75 cm^3 D). 7.48*10^2 cm^2

2 6. Which option has the highest number of significant figures? A) g B). 1.7 g C). 320.g D) g 7. Which will displace the largest volume of water when you place 20.0g of iron block with density 7.86g/cm^3 or an aluminum block of mass 20g with density 2.70g/cm^3? A). Iron block B). Aluminum block 8. Following are the mass of a 12.0g glass block weighed by four groups in consecutive trials. Which group has the precise and accurate measurement? A). 8.9g, 9.0g, 13.1g, and 12.9g Avg= 11.0g B). 10.9g, 11.6g, 14.7g and 10.5 g; Avg= 11.9g C). 9.6g, 9.8g, 9.3g and 9.4g; Avg; 9.5g D). 12.3g, 11.9g, 12.1g and 12.2; Avg=12.1g 9. How many protons, neutrons are electrons are there in a neutral Sr-88 atom? #p= 38 #e = 38 #n= The number of electrons present in V +5? #e= Carbon has two naturally occurring isotopes. C-12 has a mass of amu and abundance of 98.93%. C-13 has a mass of amu with 1.07% of abundance. Find the average atomic mass of Carbon.

3 12. The average atomic mass of Cu is 63.55amu. Cu-65 with a mass of amu has an abundance of 30.83%. What will be the mass of the other isotope Cu-63? 13. An imaginary element (Atomic mass ) has three naturally-occurring isotopes with isotopic masses of , and The abundance of the lightest isotope is %. What is the percentage abundance of the heaviest isotope?

4 14. Calculate the number of atoms in 526.0g of pure Iron block 15. Classify the following as ionic or molecular compounds a) CaCl2 b) H2S c) CaSO4 d) FeCl3 e) N2O5 f) NH4NO3 16. Write the Chemical formula

5 a) Iron (III) hydroxide b) Aluminum oxide c) Ammonium sulfate d) Potassium iodide e) Lead (II) sulfate f) Iron (III) oxide g) Potassium chlorate h) Diphosphorus pentoxide i) Dihydrogen dioxide j) Pentacarbon decoxide k) Silicon hexachloride l) Diphosphorus monobromide m) Selenium trioxide n) Tribismuth heptafluoride 17. Name the compounds: a) CuCl2 b) (NH4)2CO3 c) NaCl

6 d) FeBr3 e) H2O f) HCN g) H3PO4 h) H2SO3 i) H2Se j) H3P k) Ca(OH)2 l) Fe(OH)3

7 18. Balance the following equation C3H8O(s) + O2(g) > CO2(g) + H2O(g) 19. The burning of 18.0 g of carbon produces 55.0 g of carbon dioxide according to the reaction C(s) + O2(g) ----> CO2(g). What is the theoretical yield of CO2? Calculate the percent yield of CO2.

8 20. What is the percentage of yield if the reaction between 8.9g of nitrogen gas and 4.6 g of hydrogen gas produced 8.4g of ammonia? N2 (g) + H2 (g) 2 NH3 (g) 21. How much grams of lithium nitrate must be dissolved to get a 500.0mL 1.5M aqueous solution? 22. What will be the concentration of the aqueous solution prepared by dissolving 6.50g of calcium carbonate in water and made it up to 250mL.

9 23. What will be the final concentration if 45mL of 2.5M HCl is diluted up to 150mL mL of 0.25M PbNO3 reacted with 75.0mL of 0.1M HCl. The reaction is as follows; Pb(NO3)2(aq) + 2HCl(aq) PbCl2(S) + 2HNO3 (aq) A) Write the complete and net ionic equation. B) If the mass of PbCl2 formed were 0.86g. What is the percentage of yield of the reaction

10 25. Which of the following is insoluble? A). LiNO3 B). BaS C). PbSO4 D). (NH4)2CO3 26. What will be the change in internal energy if a system releases about 354 kj energy and the surrounding does about 120kJ of work on the system? 27. Find the work associated with the expansion of a system at 5.6L to 7.9L against an external pressure of 2.5atm in joules. 28. Consider 50.0g of iron Nickel block and 50.0mL of water, both initially at C. If we heat them separately by applying J of energy. [Specific heat capacities Ni= 0.44 J/g 0 C Water= J/g 0 C] A) Which one will have highest final temperature. B) Which one will have the lowest change in temperature. C) With the same amount of samples, for which sample we have to provide highest amount of energy for a temperature change.

11 29. The following reaction is occurring in a bomb colorimeter with heat capacity 1.56J/0C. What does the enthalpy change per mole of C6H12O6 if the temperature of the colorimeter changed by C when 12.06g reacted? C6H12O6(s) + 9O2(g) > 6CO2(g) + 12H2O(g) 30. Given the following thermochemical equations: I) N2 (g) + O2 (g) 2 NO (g) H = kj II) N2 (g) + 3 H2 (g) 2 NH3 (g) H = kj III) 2H2 (g) + O2 (g) 2 H2O (g) H = kj Calculate H for the following reaction: 4 NH3 (g) + 5 O2 (g) 4 NO (g) + 6 H2O (g)

12 31. A g sample of octane (C8H18) is burned in a bomb calorimeter containing 1200 grams of water at an initial temperature of 25.00ºC. After the reaction, the final temperature of the water is 33.20ºC. The heat capacity of the calorimeter (also known as the calorimeter constant ) is 837 J/ºC. The specific heat of water is J/g ºC. Calculate the heat of combustion of octane in kj/mole CHM 2040 IA

13 32. Two solutions initially at C are mixed in a coffee cup calorimeter that has a heat capacity of 15.5J/ 0 C. When a 100.0mL volume of 0.100M AgNO3 solution is mixed with a 100.0mL sample of 0.200M NaCl solution, the temperature in the calorimeter rises to C. determine the ΔHrxn for the reaction as written below. NaCl(aq) + AgNO3(aq) -----> AgCl(s) + NaNO3(aq) 33. Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: N2H4 (l) + CH4O(l) CH2O(g) + N2 (g) + 3H2 (g) I. 2NH3 (g) N2H4 (l) + H2 (g) ΔH = 22.5 kj II. 2NH3 (g) N2 (g) + 3H2(g) ΔH = 57.5 kj III. CH2O(g) + H2 (g) CH4O(l) ΔH = 81.2 kj

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