Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Activity 151-8 Mole Conversions
Document related concepts
Transcript
Activity 151-8 Mole Conversions Directions: This Guided Learning Activity (GLA) focuses on completing conversions between the mass, the moles and the particle number for a given chemical. Part A introduces the mole, Part B discusses basic mole conversions, and Part C discusses multistep mole conversions. These conversions are important for converting between the molecular world and every day quantities. This material is especially important for solving stoichiometry problems. The worksheet is accompanied by instructional videos. See http://www.canyons.edu/Departments/CHEM/GLA/ for additional materials. Part A β The Mole Avogadroβs number serves as a conversion factor to relate the molecular world to the macro world. ππ ππππππππ = ππ. ππππππ ππ ππππππππ ππππππππππππππππππ Avogadroβs number is defined so that the mass in grams of 1 mole of a substance is equal to the mass in atomic mass units of one formula unit of the substance. Therefore, both the formula mass (the mass of one particle) and the molar mass (the mass of one mole of particles) can be found by adding the numerical mass of each elemental component that is given on the periodic table. What is the atomic mass of an element? ________________________________________________ What unit is used to measure atomic mass? _____________________________________________ What is a formula unit? _____________________________________________________________ How are molar mass and formula mass different? ________________________________________ Example #1a. What is the formula mass of each of the following elements or compounds? Magnesium (Mg) __________________ Iron (III) ion (Fe3+) __________________ Water (H2O) __________________ Acetic acid (HC2H3O2) __________________ Example #1b. What is the molar mass for each substance in part a? Chemistry Guided Learning Activities Activity 151 β 8 College of the Canyons Page 1 of 3 Part B β Basic Mole Conversions Using the mole, scientists can convert easily between mass, moles and particle numbers for substances. Mass Moles Molar Mass (in grams/mole) Particles NA 23 (6.022 x 10 particles/mole) Example #2. Perform the following conversions. ππππππ. ππππ ππ ππππππππππ ππ. ππππ ππππππππ ππππππππππ οΏ½ οΏ½ = ππππππ. ππ ππππππππππ ππ ππππππππ ππππππππππ β ππππ. ππ ππ π΅π΅πΆπΆβ ππ = ____________ ππππππππ π΅π΅πΆπΆππ ππ. ππππ ππππππππ π΅π΅π΅π΅π΅π΅π΅π΅ = _____________ π΅π΅π΅π΅π΅π΅π΅π΅ ππππππππππππππ ππππππππππ ππ. ππππ ππ ππππππππ π©π©π©π© ππππππππππ = ____________ ππππππππππ π©π©π©π© Part C β More Mole Conversions Often in chemistry, students must interpret what information is being requested in a word problem. This section practices identifying the requested quantity and using mole conversions to determine the answer. Example #3. Use mole conversions to answer the following questions. a. What is the mass of 7.00 x 1028 water molecules (H2O)? ππ. ππππππππππππππ π―π―ππ πΆπΆ ππππππππππππππππππ ππ ππππππππ π―π―ππ πΆπΆ ππππ. ππππ ππ π―π―ππ πΆπΆ οΏ½ οΏ½ οΏ½ = ππ. ππππππππππππ ππ π―π―ππ πΆπΆ οΏ½ οΏ½οΏ½ ππ ππ. ππππππππππππππππ ππππππππππππππππππ ππ ππππππππ π―π―ππ πΆπΆ b. How many molecules are in 47.9 g of oxygen gas (O2)? c. How many sodium ions does 15.0 g of sodium oxide, Na2O, contain? Chemistry Guided Learning Activities Activity 151 β 8 College of the Canyons Page 2 of 3 Part D β Extra Practice 1. Fill in the table below. Which of the samples listed has the greatest mass? Which contains the largest number of carbon atoms? Substance Molar Mass (g/mol) Mass (g) Carbon (C ) Carbon Dioxide (CO2) Acetic Acid (HC2H3O2) Moles # Carbon atoms 0.0581 100.0 g 6.022x1023 3.5 x 1024 Carbonate ion (CO32-) Sucrose (C12H22O11) # Particles 100.0 g 2. How many moles of Ca2+ ions are present in 5.67 moles of calcium phosphate, Ca3(PO4)2? 3. Which contains more nitrogen, 50.0 g of ammonia (NH3) or 100.0 g of ammonium nitrate (NH4NO3)? 4. How many helium atoms are present in 65 kg sample of helium? 5. War nickels, produced from 1942-1945 are composed of 56% copper, 35% silver and 9% manganese. How many moles of each element are found in a 5.00 g nickel coin? (Hint: There are 56 g of copper in 100 g of nickel coins.) Chemistry Guided Learning Activities Activity 151 β 8 College of the Canyons Page 3 of 3
