Moles and Stoichiometry 2016

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molecular formula N2O4? A) NO B) NO2 C) N2O D) N2O3 2.

NH3? A) 1 mole B) 2 moles C) 3 moles D) 4 moles 3.

What is the empirical formula of glucose?

What is the total number of moles of atoms represented by

What is the chemical formula for zinc carbonate?

A compound has the empirical formula CH2O and a

What is the molecular formula of this compound?

What is the gram formula mass of (NH4)2SO4? A) 66.

What is the total mass of 2.0 moles of H2(g)? A) 1.

The number of moles of molecules in a -gram sample of is

Which quantity is equivalent to 39 grams of LiF? A) 1.

5 moles A) SO B) SO2 C) SO3 D) S2O3 Date: Mrs. Mannion 11.

What is the empirical formula of this compound? 12.

80) is approximately A) 18% B) 23% C) 32% D) 35% 13.

14. Which compound has the highest percent composition by

What is the percent by mass of water present in 1.

What is the percent composition by mass of nitrogen in

1 Name: Moles and Stoichiometry What is the empirical formula of a compound with the molecular formula N2O4? A) NO B) NO2 C) N2O D) N2O3 2. What is the total number of atoms contained in 1 mole of NH3? A) 1 mole B) 2 moles C) 3 moles D) 4 moles 3. The molecular formula of glucose is C6H12O6. What is the empirical formula of glucose? A) CHO B) CH2O C) C6H12O6 D) C12H24O12 4. What is the total number of moles of atoms represented by the formula Al(C2H3O2)3? A) 22 B) 11 C) 8 D) 4 5. What is the chemical formula for zinc carbonate? A) ZnCO3 B) Zn(CO3)2 C) Zn2CO3 D) Zn2CO2 6. A compound has the empirical formula CH2O and a gram-formula mass of 60. grams per mole. What is the molecular formula of this compound? A) CH2O B) C2H4O2 C) C3H8O D) C4H8O4 7. What is the gram formula mass of (NH4)2SO4? A) 66.0 g B) 94.0 g C) 114 g D) 132 g 8. What is the total mass of 2.0 moles of H2(g)? A) 1.0 g B) 2.0 g C) 3.0 g D) 4.0 g 9. The number of moles of molecules in a -gram sample of is A) mole B) mole C) moles D) moles 10. Which quantity is equivalent to 39 grams of LiF? A) 1.0 mole B) 2.0 moles C) 0.50 mole D) 1.5 moles A) SO B) SO2 C) SO3 D) S2O3 Date: Mrs. Mannion 11. A compound contains 57% sulfur and 43% oxygen by mass. What is the empirical formula of this compound? 12. The percent by mass of nitrogen in NH4NO3 (formula mass = 80) is approximately A) 18% B) 23% C) 32% D) 35% 13. The percent by mass of oxygen in is equal to A) B) C) D) 14. Which compound has the highest percent composition by mass of strontium? A) B) C) D) 15. What is the percent by mass of water present in 1.0 mole of CaSO4 2H2O? A) 10.% B) 12% C) 21% D) 79% 16. What is the percent composition by mass of nitrogen in NH4NO3 (gram-formula mass = 80.0 grams/mole)? A) 17.5% B) 35.0% C) 52.5% D) 60.0% 17. Given the balanced equation representing a reaction: Which type of reaction is represented by this equation? A) decomposition B) double replacement C) single replacement D) synthesis 18. During all chemical reactions, mass, energy, and charge are A) absorbed B) conserved C) formed D) released

2 19. The coefficients in a balanced chemical equation represent A) the mass ratios of the substances in the reaction B) the mole ratios of the substances in the reaction C) the total number of electrons in the reaction D) the total number of elements in the reaction 20. When the equation is correctly balanced using the smallest whole number coefficients, the sum of the coefficients is A) 9 B) 8 C) 5 D) Given the balanced equation: CaCO3(s) + 2HCl(aq) (g) CaCl2(aq) + H2O( ) + CO2 What is the total number of moles of CO2 formed when 20. moles of HCl is completely consumed? A) 5.0 mol B) 10. mol C) 20. mol D) 40. mol 22. Given the reaction: Mg + 2 HCl MgCl2 + H2 What is the total number of grams of Mg consumed when 0.50 mole of H2 is produced? A) 6.0 g B) 12 g C) 3.0 g D) 24 g 23. Given the balanced equation representing a reaction: CaO(s) + CO2(g) CaCO3(s) + heat What is the total mass of CaO(s) that reacts completely with 88 grams of CO2(g) to produce 200. grams of CaCO3(s)? A) 56 g B) 88 g C) 112 g D) 288 g 24. What is the total number of neon atoms contained in 20.2 grams of neon gas? A) B) C) D)

25. Base your answer to the following question on the information below.

Determine the percent composition by mass of oxygen in the compound C6H12O6 27. Show a numerical setup for calculating the percent composition by mass of silicon in. 28.

On impact, the NaN3(s) is ignited by an electrical spark, producing N2(g) and Na(s). The N2(g) inflates the airbag. What is the total number of moles present in a 52.

3 25. Base your answer to the following question on the information below. A scientist in a chemistry laboratory determined the molecular formulas for two compounds containing nitrogen and oxygen to be NO2 and N2O5 Write an IUPAC name for the compound N2O Determine the percent composition by mass of oxygen in the compound C6H12O6 27. Show a numerical setup for calculating the percent composition by mass of silicon in. 28. Base your answer to the following question on the information below. The decomposition of sodium azide, NaN3(s), is used to inflate airbags. On impact, the NaN3(s) is ignited by an electrical spark, producing N2(g) and Na(s). The N2(g) inflates the airbag. What is the total number of moles present in a 52.0-gram sample of NaN3(s) (gram- formula mass = 65.0 gram/mole)? 29. Base your answer to the following question on the information below. John Dalton, an early scientist, sketched the structure of compounds using his own symbols for the elements known at the time. Dalton's symbols for four elements and his drawing of potassium aluminum sulfate are represented by the diagram below. Today, it is known that the chemical formula for potassium aluminum sulfate is. It is a hydrated compound because water molecules are included within its crystal structure. There are 12 moles of H2O for every 1 mole of. The compound contains two different positive ions. The gram-formula mass of is 474 grams per mole. Show a numerical setup for calculating the percent composition by mass of water in.

30. Base your answer to the following question on the information below. In an experiment, 2.

Determine the total mass of sulfur consumed. 31. Base your answer to the following question on the information below.

Show a correct numerical setup for calculating the molarity of the solution. 32.

Round atomic masses from the Periodic Table to the nearest tenth. [Show all work.

Calculate the number of moles of KClO3(s) produced. [Show all work. Indicate the correct answer in proper significant figures.] 33.

Base your answers to the following questions on the information below.

50 ppm of chlorine is added to drinking water to make it safe. In 2.0 liters of drinking water (2000.

4 30. Base your answer to the following question on the information below. In an experiment, 2.54 grams of copper completely reacts with sulfur, producing 3.18 grams of copper(i) sulfide. Determine the total mass of sulfur consumed. 31. Base your answer to the following question on the information below. In a titration, milliliters of a solution exactly neutralized milliliters of a solution. Show a correct numerical setup for calculating the molarity of the solution. 32. In a laboratory experiment, a student determined the mass of the product, KClO3(s), to be 45.7 grams. a. Calculate the gram formula mass of KClO3(s). Round atomic masses from the Periodic Table to the nearest tenth. [Show all work. Indicate the correct answer in proper significant figures and include an appropriate unit.] b. Calculate the number of moles of KClO3(s) produced. [Show all work. Indicate the correct answer in proper significant figures.] 33. Determine the molecular formula for a compound that has the empirical formula and a molar mass of 120. grams per mole. 34. Base your answers to the following questions on the information below. For health reasons, the element chlorine is added to the drinking water because it will kill disease-causing organisms. Typically 0.50 ppm of chlorine is added to drinking water to make it safe. In 2.0 liters of drinking water (2000.g), how many grams of chlorine is present? [Show all work. Include in your answer proper units and significant figures.] 35. The decomposition of sodium azide, NaN3(s), is used to inflate airbags. On impact, the NaN3(s) is ignited by an electrical spark, producing N2(g) and Na(s). The N2(g) inflates the airbag. An inflated airbag has a volume of 5.00 x 10 4 cm 3 at STP. The density of N2(g) at STP is g/cm 3. What is the total number of grams of N2(g) in the airbag?

36. Base your answer to the following question on the information below and on your knowledge of chemistry. Many breads are made by adding yeast to dough, causing the dough to rise.

Determine the total mass of ethanol produced when 270. grams of glucose reacts completely to form ethanol and 132 grams of carbon dioxide. 37.

5 36. Base your answer to the following question on the information below and on your knowledge of chemistry. Many breads are made by adding yeast to dough, causing the dough to rise. Yeast is a type of microorganism that produces the catalyst zymase, which converts glucose,, to ethanol and carbon dioxide gas. The balanced equation for this reaction is shown below. Determine the total mass of ethanol produced when 270. grams of glucose reacts completely to form ethanol and 132 grams of carbon dioxide. 37. Base your answer to the following question on the passage below. Acid rain is a problem in industrialized countries around the world. Oxides of sulfur and nitrogen are formed when various fuels are burned. These oxides dissolve in atmospheric water droplets that fall to earth as acid rain or acid snow. While normal rain has a ph between 5.0 and 6.0 due to the presence of dissolved carbon dioxide, acid rain often has a ph of 4.0 or lower. This level of acidity can damage trees and plants, leach minerals from the soil, and cause the death of aquatic animals and plants. If the ph of the soil is too low, then quicklime, CaO, can be added to the soil to increase the ph. Quicklime produces calcium hydroxide when it dissolves in water. Acid rain is a problem in industrialized countries around the world. Oxides of sulfur and nitrogen are formed when various fuels are burned. These oxides dissolve in atmospheric water droplets that fall to earth as acid rain or acid snow. While normal rain has a ph between 5.0 and 6.0 due to the presence of dissolved carbon dioxide, acid rain often has a ph of 4.0 or lower. This level of acidity can damage trees and plants, leach minerals from the soil, and cause the death of aquatic animals and plants. If the ph of the soil is too low, then quicklime, CaO, can be added to the soil to increase the ph. Quicklime produces calcium hydroxide when it dissolves in water. Balance the neutralization equation below, using the smallest whole number coefficients. 38. Base your answer to the following question on the information below. The reaction between aluminum and an aqueous solution of copper(ii) sulfate is represented by the unbalanced equation below. Identify the type of chemical reaction represented by the equation.

Answer Key Moles and Stoichiometry 2016 1. B 2. D 3. B 4. A 5. A 6. B 7. D 8. D 9. B 10. D 11. D 12. D 13. B 14.

Responses include, but are not limited to, these examples: dinitrogen pentoxide nitrogen(v) oxide 26. 53.3% 27. 28.

0.64 g 31. 32. a) 39.1 + 35.5 + 3(16.0) = 122.6 g b) 45.7g x 1.00 mole/122.6g =.373 mole 33.

6 Answer Key Moles and Stoichiometry B 2. D 3. B 4. A 5. A 6. B 7. D 8. D 9. B 10. D 11. D 12. D 13. B 14. C 15. C 16. B 17. C 18. B 19. B 20. A 21. B 22. B 23. C 24. D 25. Responses include, but are not limited to, these examples: dinitrogen pentoxide nitrogen(v) oxide % Significant figures do not need to be shown. Acceptable responses include, but are not limited to: mol g a) (16.0) = g b) 45.7g x 1.00 mole/122.6g =.373 mole 33.. The order of the elements can vary g g g or for any value from g to g, inclusive HNO3 + 1 Ca(OH) 2 1 Ca(NO3)2 + 2 H2O 38. single replacement redox

Practice Test. Moles & Stoich. Page What is the total number of nitrogen atoms in 0.25 mole of NO2 gas? (1)

Practice Test. Moles & Stoich. Page What is the total number of nitrogen atoms in 0.25 mole of NO2 gas? (1) 1. What is the total number of nitrogen atoms in 0.25 mole of NO2 gas? (1) 1.5 10 23 (3) 3.0 10 23 (2) 6.0 10 23 (4) 1.2 10 24 2. Which quantity of O2 contains exactly 3.01 10 23 molecules? (1) 0.250 mole