How can we predict the amounts of substances in a chemical reaction?

How can we predict the amounts of substances in a chemical reaction?
Unit 3: Holey Moley How does the mole concept illustrate constant composition and conservation of mass? How can we predict the amounts of substances in a chemical reaction?

Drill 1: 11/21 (A Day) 11/27 (B Day)
Prepare for dimensional analysis quiz. Outcome: I can convert between units of grams, liters, and number of particles using the mole.

CW 1: The Mole

CW 1: The Mole How many trunks are found in one dozen elephants?
1 elephant = 1 trunks, 12 elephants = 12 trunks How many legs are found in one dozen elephants? 1 elephant = 4 legs… So 12 elephants have 4 X 12 legs, 48 legs How many carbon atoms are found in one dozen methane (CH4) molecules? 1 methane = 1 C, 12 methanes = 12 C atoms How many hydrogen atoms are found in one dozen methane molecules? 1 methane = 4 H atoms … So 12 methanes have 12 × 4 hydrogens, 48 hydrogens

CW 1: The Mole How many trunks are found in one mole of elephants?
1 mole = 6.02x1023 elephants. Each have 1 trunk… 6.02x1023 trunks How many legs are found in one mole of elephants? 1 elephant = 4 legs. 4 legs × (6.02X1023) = 24.08x1023 legs How many carbon atoms are found in one mole of methane molecules? 1 methane = 1 C atom. 1 atom × (6.02x1023) = 6.02x1023 C atoms How many hydrogen atoms are found in one mole of methane molecules? 1 methane = 4 H atoms. 4 atoms × (6.02x1023)= x1023 H atoms

CW 1: The Mole How is “a mole” similar to “a dozen”?
A dozen is always 12, like a mole is always 6.02x1023. A mole is equal to 6.02x1023 items, which is a very large number. Why would chemists want to use moles as the unit to count atoms in? Atoms are very small, so we need a lot of them before they are measurable.

Particles = atoms, molecules, etc. Liters
At standard temperature and pressure (STP) X g = 1 mol

CW 1: The Mole Find the molar mass of the following compounds.
Sulfur Dioxide Lead (II) Nitrate Phosphoric Acid Ammonium Sulfate SO2 = 64.1 g/mol Pb(NO3)2 = g/mol H3PO4 = 97.9 g/mol (NH4)2SO4 = g/mol

CW 1: The Mole Explain in words or pictures how to convert from 1.56x1030 particles of sodium chloride to grams of sodium chloride. 1.56x1030 particles NaCl Avogadro’s Number moles NaCl Molar Mass grams NaCl

CW 1: The Mole Explain in words or pictures how to convert from 1.56x1030 particles of sodium chloride to grams of sodium chloride. Solve. The answer is given so you can check your work. particles moles grams 1.56× 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠 1 × 1 𝑚𝑜𝑙 6.02×10 23 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒𝑠 × 58.4 𝑔 1 𝑚𝑜𝑙 𝑁𝑎𝐶𝑙 = 𝑔

CW 1: The Mole Question 14 Perform the following conversions.
How many oxygen molecules are in 3.36 L of oxygen gas at STP? (Answer: 9.03x1021 molecules) Find the mass in grams of 2.00x1023 molecules of F2. (Answer:12.6 g) 3.36 𝐿 𝑔𝑎𝑠 1 × 1 𝑚𝑜𝑙 22.4 𝐿 × 6.02×10 23 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 1 𝑚𝑜𝑙 = 9.03×10 21 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 2.00× 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 𝐹 2 1 × 1 𝑚𝑜𝑙 6.02×10 23 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 × 38 𝑔 1 𝑚𝑜𝑙 𝐹 2 =12.6 𝑔

CW 1: The Mole Question 14 Perform the following conversions.
Determine the volume in liters occupied by 14 g of nitrogen gas at STP. (Answer: 11 L) Find the mass, in grams, of 1.00x1023 molecules of N2. (Answer: 4.65 g) 14 𝑔 𝑁 2 𝑔𝑎𝑠 1 × 1 𝑚𝑜𝑙 𝑁 𝑔 × 22.4 𝐿 1 𝑚𝑜𝑙 =11 𝐿 1.00× 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 𝑁 2 1 × 1 𝑚𝑜𝑙 6.02×10 23 𝑚𝑜𝑙𝑒𝑐𝑢𝑙𝑒𝑠 × 28 𝑔 1 𝑚𝑜𝑙 𝑁 2 =4.65 𝑔

Summary 1: 11/21 (A Day) 11/27 (B Day)
HW 1: Mole Calculations Practice Complete CW 1 8 Formal Report due on 11:45 on 12.12 Outcome: I can convert between units of grams, liters, and number of particles using the mole.

Drill 2: 11/28 (A Day) 11/29 (B Day)
Use the mole road map to set up (DO NOT SOLVE) the following: How many grams does 3 L of oxygen gas weigh? What is the mass of 2.5 moles of calcium chloride? Outcome: I can calculate the empirical formula from percent composition.

CW 2: Finding Empirical Formula
Find the % composition of oxygen in H2O. Molar Mass of Compound: H2O Molar Mass of Element: O 𝐻:1.01×2=2.02 𝑔/𝑚𝑜𝑙 O:16.00×1=16.00 𝑔/𝑚𝑜𝑙 O:16.00×1=16.00 𝑔/𝑚𝑜𝑙 =18.02 𝑔/𝑚𝑜𝑙 % 𝐶𝑜𝑚𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛 𝑂= ×100%=88.79% 𝑂

Verify that the % composition given for ethyne in Table 1 is correct. Molar mass of C2H2: 2(12.011) + 2(1.008) = Molar mass of C in C2H2: 2(12.01) = % Composition C: Molar Mass of H in C2H2: 2(1.01) = 2.016 % Composition H: ×100%= % ×100%=7.742 %

Fill in the missing info in Table 1. C6H6 92.26 7.74 85.63 14.37 C4H8 14.37 C8H16 85.63 14.37

Can you determine the % composition by mass of H for 2-butene without using the equation given in model 1? If so, how? The total will always be 100 %. Subtract the % C from 100, what is left is % H.

Compare the molecular formulas. Can you determine the molecular formula of a compound solely from its percent composition? Why or why not? No, cyclobutane, 2-butene, and 1-octene all have the same % composition, but they all have different molecular formulas.

Agree or disagree: compounds with the same percent composition have the same molecular formula. Provide an example to support your position. Disagree! The formula is different (ethyne and benzene), but they do have the same ratio of elements, 1C : 1 H ratio

Molecular Formula Simplest whole number ratio of elements CH3 Some multiple of the empirical formula C2H6; C3H9; etc.

What feature related to the composition of a compound can be determined solely by percent composition? The simplest ratio of elements: empirical formula Determine the empirical formula of each of the molecules in Table 1. Name Molecular Formula Empirical Formula Ethyne C2H2 CH Benzene C6H6 Cyclobutane C4H8 CH2 2-butene 1-octene C8H16

A molecule containing only nitrogen and oxygen contains (by mass) 36.8% N. How many grams of N would be found in a 100 g sample of the compound? How many grams of O would be found in the same sample? 36.8% of 100 g = 36.8 g N 100% % = 63.2% O 63.2% of 100 g = 63.2 g O

A molecule containing only nitrogen and oxygen contains (by mass) 36.8% N. How many moles of N would be found in a 100 g sample of the compound? How many moles of O would be found in the same sample? 36.8 𝑔 𝑁 1 × 1 𝑚𝑜𝑙 𝑁 𝑔 𝑁 =2.63 𝑚𝑜𝑙 𝑁 63.2 𝑔 𝑂 1 × 1 𝑚𝑜𝑙 𝑂 𝑔 𝑂 =3.95 𝑚𝑜𝑙 𝑂

A molecule containing only nitrogen and oxygen contains (by mass) 36.8% N. What is the ratio of the number of moles of O to the number of moles of N? What is the empirical formula of the compound? Need to make the 1.5 a whole # 2.63 𝑚𝑜𝑙 𝑁÷2.63 𝑚𝑜𝑙=1 ×2 =2 3.95 𝑚𝑜𝑙 𝑂÷2.63 𝑚𝑜𝑙=1.5 ×2 =3 𝑁 2 𝑂 3

The molecule 2-hexene has the molecular formula C6H12. Refer to Table 1 and determine the percent composition of H in this molecule. Determine the percent composition of carbon in acetic acid, HC2H3O2. Molecular Formula Empirical Formula % H C6H12 CH2 14.37 Molar Mass: g/mol C: 12.01×2 = g/mol (24.02/60.06)×100% = 39.99%

A compound used as a dry-cleaning fluid was analyzed and found to contain 18.00% C, 2.27% H, and 79.73% Cl. Determine the empirical formula of the fluid. C2H3Cl3 18.00 𝑔 𝐶 1 × 1 𝑚𝑜𝑙 𝐶 𝑔 =1.499 𝑚𝑜𝑙÷1.499=1×2=2 2.27 𝑔 𝐻 1 × 1 𝑚𝑜𝑙 𝐻 𝑔 =2.252 𝑚𝑜𝑙÷1.499=1.5×2=3 79.73 𝑔 𝐶𝑙 1 × 1 𝑚𝑜𝑙 𝐶𝑙 𝑔 =2.249 𝑚𝑜𝑙÷1.499=1.5×2=3

A compound was analyzed and found to contain 13.5 g Ca, 10.8 g O, and g H. 13.5 𝑔 𝐶𝑎 1 × 1 𝑚𝑜𝑙 𝐶𝑎 𝑔 =0.337 𝑚𝑜𝑙÷0.337=1 CaO2H2 or Ca(OH)2 10.8 𝑔 𝑂 1 × 1 𝑚𝑜𝑙 𝑂 𝑔 =0.675 𝑚𝑜𝑙÷0.337=2 0.675 𝑔 𝐻 1 × 1 𝑚𝑜𝑙 𝐻 𝑔 =0.670 𝑚𝑜𝑙÷0.337=2

The empirical formula of a compound is NO2. Its molecular mass is 92 g/mol. What is its molecular formula? Determine the molar mass of NO2. Divide the molecular mass by the molar mass. You should get a whole number. Multiply the subscripts in NO2 by the whole number you got in the last step. 𝑁:1×14.007= 𝑔 = 𝑔/𝑚𝑜𝑙 O:2×15.999= 𝑔 92 𝑔/𝑚𝑜𝑙 𝑔/𝑚𝑜𝑙 =2 N2O4

The empirical formula of a compound is CH2. Its molecular mass is 70 g/mol. What is its molecular formula? 2. Divide molecular mass by molar mass 1. Find molar mass C:1×12.011= 𝑔 70 𝑔/𝑚𝑜𝑙 𝑔/𝑚𝑜𝑙 =5 H:2×1.008=2.016 𝑔 = 𝑔/𝑚𝑜𝑙 3. Multiply each subscript by the number found above. C5H10

A compound is found to be 40.0% carbon, 6.7% hydrogen and 53.5% oxygen. Its molecular mass is 60 g/mol. What is the empirical formula? What is the molecular formula? 40.0 𝑔 𝐶 1 × 1 𝑚𝑜𝑙 𝐶𝑎 𝑔 =3.33 𝑚𝑜𝑙÷3.33=1 6.75 𝑔 𝐻 1 × 1 𝑚𝑜𝑙 𝐻 𝑔 =6.69 𝑚𝑜𝑙÷3.33=2 CH2O 53.5 𝑔 𝑂 1 × 1 𝑚𝑜𝑙 𝑂 𝑔 =3.34 𝑚𝑜𝑙÷3.33=1 Molar Mass CH2O: g/mol 60 𝑔/𝑚𝑜𝑙 𝑔/𝑚𝑜𝑙 =2 C2H4O2

Complete CW 1 to 2 if not done Science Research: Final Report due 12/6 (A Day) and 12/7 (B Day) No online submission Formal report or display board Boards on sale: $3 Science Fair: 12/14 after school Extra credit for competing If you are competing, write your name on the back board HW 1: The Strange Case of Mole Airlines Outcome: I can calculate the empirical formula from percent composition.

Drill 3: 11/30 (A Day) 12/1 (B Day)
Ms. L’s silver wedding band has a mass of g. How many atoms of silver are present? If the ring was made of gold, would there be more atoms or less atoms? 11.3 𝑔 𝐴𝑔 1 × 1 𝑚𝑜𝑙 𝐴𝑔 𝑔 𝐴𝑔 × 6.02× 𝑎𝑡𝑜𝑚𝑠 𝐴𝑔 1 𝑚𝑜𝑙 𝐴𝑔 = 6.31× 𝑎𝑡𝑜𝑚𝑠 𝐴𝑔 Outcome: I can determine the formula of a hydrate by solving for the empirical formula. 11.3 𝑔 𝐴𝑔 1 × 1 𝑚𝑜𝑙 𝐴𝑔 𝑔 𝐴𝑔 × 6.02× 𝑎𝑡𝑜𝑚𝑠 𝐴𝑔 1 𝑚𝑜𝑙 𝐴𝑔 = This number would be bigger (molar mass Au = g/mol) So the answer would be a smaller number of atoms.

CW 3: Composition of Hydrates
A hydrate is an ionic compound (salt) with water molecules loosely bonded to its crystal structure. The water is in a specific ratio to each formula unit of the salt. For example, the formula MgSO4·7H2O indicates that there are seven water molecules for every one formula unit of MgSO4.

What percentage of water is found in Na2S·9H2O? 𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝐻 2 𝑂 𝑖𝑛 𝑐𝑜𝑚𝑝𝑜𝑢𝑛𝑑 𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑐𝑜𝑚𝑝𝑜𝑢𝑛𝑑 (𝑤𝑖𝑡ℎ 𝐻 2 𝑂) ×100% 𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 9 𝐻 2 𝑂 𝑚𝑜𝑙𝑎𝑟 𝑚𝑎𝑠𝑠 𝑁𝑎 2 𝑆∙9 𝐻 2 𝑂 ×100% 𝑔/𝑚𝑜𝑙 𝑔/𝑚𝑜𝑙 ×100%=67.51% 𝐻 2 𝑂

A 5.0 g sample of a hydrate of Cu(NO3)2 was heated, and only 3.9 g of the anhydrous salt remained. What percentage of water was in the hydrate? Determine how many moles of anhydrous Cu(NO3)2 are present. Determine how many moles of H2O were present before heating. Determine the formula of the hydrate (similar to finding the empirical formula, divide each of the answers in B and C by the smallest number of moles to get whole numbers). 1.1 𝑔 𝐻 2 𝑂 5.0 𝑔 𝑇𝑜𝑡𝑎𝑙 ×100%=22% 5.0 𝑔−3.9 𝑔=1.1 𝑔 𝐻 2 𝑂 3.9 𝑔 𝐶𝑢 𝑁𝑂 × 1 𝑚𝑜𝑙 𝐶𝑢 𝑁𝑂 𝑔 𝐶𝑢 𝑁𝑂 = 𝑚𝑜𝑙 𝐶𝑢 𝑁𝑂 3 2 ÷0.0208 =1 1.1 𝑔 𝐻 2 𝑂 1 × 1 𝑚𝑜𝑙 𝐻 2 𝑂 𝑔 𝐻 2 𝑂 = 𝑚𝑜𝑙 𝐻 2 𝑂 ÷0.0208 =3 𝐶𝑢 (𝑁𝑂 3 ) 2 ∙3 𝐻 2 𝑂

A group of students wanted to determine the formula of a hydrate of MgCO3. How much of the hydrate did they add to the crucible? How much water did they remove from the hydrate? What is the mass of the anhydrous compound? Mass empty crucible 50.43 g Mass of crucible with sample 66.10 g Mass of crucible with sample after heating 58.01 g 66.10 𝑔 −50.43 𝑔=15.67 𝑔 ℎ𝑦𝑑𝑟𝑎𝑡𝑒 66.10 𝑔 −58.01 𝑔=8.09 𝑔 𝐻 2 𝑂 15.67 𝑔 −8.09 𝑔=7.58 𝑔 𝑀𝑔𝐶𝑂 3

A group of students wanted to determine the formula of a hydrate of MgCO3. What is the formula of the hydrate? Mass empty crucible 50.43 g Mass of crucible with sample 66.10 g Mass of crucible with sample after heating 58.01 g 𝑀𝑔𝐶𝑂 3 ∙5 𝐻 2 𝑂 7.58 𝑔 𝑀𝑔𝐶𝑂 3 1 × 1 𝑚𝑜𝑙 𝑀𝑔𝐶𝑂 𝑔 𝑀𝑔𝐶𝑂 3 = 𝑚𝑜𝑙 𝑀𝑔𝐶𝑂 3 ÷0.0899=1 8.09 𝑔 𝐻 2 𝑂 1 × 1 𝑚𝑜𝑙 𝐻 2 𝑂 𝑔 𝐻 2 𝑂 =0.449 𝑚𝑜𝑙 𝐻2𝑂÷0.0899=5

You will be given an unknown hydrate of copper (II) sulfate. Explain the experimental steps and calculations. Look at question 3 – consider what information you needed to solve the problem. Materials: Striker A hydrate of copper (II) sulfate Crucible Bunsen burner to drive off water Clay triangle Ring stand Procedure: Wash and dry a porcelain crucible. Use a sharpie marker to write the initials of one group member on the crucible for later retrieval. Determine the mass of the empty crucible. Add small amount (spatula tip full) of copper sulfate hydrate to crucible. Remass the crucible to determine the exact mass of copper sulfate hydrate added. Place crucible into oven (overnight) to drive off water. Remove crucible, allow to cool, and remass. Determine the exact mass of water that was driven off. Other Notes: Samples we are using are leftovers from another lab, likely to be impure. This may throw off calculations. Ring Tongs Scale

Complete the following, showing all work. Neatly write up the answers, and submit them to your teacher. Perform the following calculations NEATLY SHOWING ALL WORK: Calculate the exact mass of the hydrate that was added to the evaporating dish. Calculate the mass of the final residue (after heating) Calculate the mass of the water that was driven off Find the percentage of water that was driven off Determine the formula of the hydrate based on your data The actual formula of the hydrate is CuSO4 · 5H2O. Based on this formula, calculate the actual percentage of water. Calculate the percent error, using the experimental value you found in question 1d and the actual value your found in question 2. Discuss possible sources of error and how they affected your data. NOTE: “plugging in numbers wrong” or miscalculations are NOT sources of error, as you can easily go back and fix these. Think about the data you collected and what could have gone wrong with those measurements.

Complete Lab Write Up (NOT a full write up). Complete CW 1 to 3 if not done Science Research: Final Report due 12/6 (A Day) and 12/7 (B Day) No online submission Formal report or display board Boards on sale: $3 Science Fair: 12/14 after school Extra credit for competing If you are competing, write your name on the back board Polyatomic ion quiz is soon… Outcome: I can determine the formula of a hydrate by solving for the empirical formula.

Drill 4: 12/4 (A Day) 12/5 (B Day)
A compound is found to be 7.2% P and 92.8% Br. What is the empirical formula? If the molecular mass is 862 g/mol, what is the molecular formula. 𝑃𝐵𝑟 5 7.2 𝑔 𝑃 1 × 1 𝑚𝑜𝑙 𝑃 𝑔 𝑃 =0.232 𝑚𝑜𝑙 𝑃 Outcome: I can explain the effect of phosphate pollution on the Chesapeake Bay. =1 ÷0.232 92.8 𝑔 𝐵𝑟 1 × 1 𝑚𝑜𝑙 𝐵𝑟 𝑔 𝐵𝑟 =1.161 𝑚𝑜𝑙 𝐵𝑟 =5 ÷0.232 Molar Mass PBr5 862 𝑔/𝑚𝑜𝑙 𝑔/𝑚𝑜𝑙 =2 P: x 1 = Br: x 5 = 𝑃 2 𝐵𝑟 10 g/mol

Phosphates in the Bay Project
According to the Environmental Protection Agency, “nutrient pollution is one of the most widespread, costly, and challenging” environmental issues that faces America. Nutrient pollution impacts all bodies of water, often entering through creeks and streams, flowing downstream into lakes, rivers, and bays. These excess nutrients can soak into ground water, affecting the drinking water source of millions of Americans. They can even impact air quality. One of the major bodies of water affected by nutrient pollution is the Chesapeake Bay. As Marylanders, our lives are connected to the Bay – it sustains our economy through tourism, fishing, and boating. We eat food that comes from the Bay. We spend time during the summer at its beaches. We drive over its bridges and enjoy its views. It is considered a national treasure. The issue of nutrient pollution rests at the intersection of social, political, and environmental concerns. We have a responsibility to understand these concerns and their causes and solutions through evidence based science. We cannot believe that this is a problem for someone else to solve, or that we lack the ability to impact this issue. We will explore our role in solving this problem through this project, which will culminate in a community outreach program.

Each of these sections will be organized and documented through a webpage that you will create. Your teacher will generate a grade for each part using the rubrics in the project packet through this webpage. You will be paired up with a group who you will peer evaluate using the provided rubrics. You will need to download a copy of these from SRHSchem and send it to the group you are evaluating. Another group will do the same for you. You must post the rubric on your website. Understanding the Problem Create a product using a web 2.0 tool of your choice that include the following key concepts: A visual explanation of how phosphate pollution enters the Chesapeake Bay (using pictures and words). The effects of phosphate pollution on the Chesapeake Bay ecosystem in concrete terms such as ecosystem failure and economic costs. Include the final product on your website or wiki with the heading “Understanding the Problem.” Peer evaluate another group’s work using the rubric. Send them a digital copy to post on their website.

Framing the Problem Use the internet to locate one recent (within the last 10 years) news article, report, or government document that describes the issue of nutrient pollution from each of the following perspectives: Environmental, Political, Economic Summarize each of the articles/ reports/ documents and explain how it relates to each perspective. Organize this information into a four-column table (name and link to source, citation, summary, and how it relates to the perspective) and include it on your website or wiki with the heading “Framing the Problem.” Peer evaluate another group’s work using the rubric. Send them a digital copy to post on their website. Solving the Problem Describe a chemistry laboratory procedure to remove phosphates from a sample of water. Describe another means to remove or prevent phosphates from entering the Bay. Compare these two methods in terms of feasibility and effectiveness. Which method is better for improving water quality? Include this information on your website or wiki with the heading “Solving the Problem.”

Outreach Program Plan and execute an outreach program to communicate what you have learned with the community using the Outreach Program Proposal. Peer evaluate another group’s proposal using the Peer Outreach Evaluation Rubric. Send them a digital copy to post on their website. Provide evidence that your outreach program was successful.

Helpful Items Useful Websites about Nutrient Pollution Finding the Perspective of a Source Suggested Websites and Tools Suggested Outreach Programs Checklist for Good Websites/ Wikis

A Day B Day Items to Complete 12/4 12/5 Complete and sign the group agreement, hand in one copy per group Review the group evaluation form Create website, share login credentials or make multiple accounts so all members can access and edit the website Choose web 2.0 tool (“Understanding the Problem,”) begin work Research for sources (“Framing the Problem”) Due by 12/15: Complete web 2.0 product (“Understanding the Problem”) and post Organize sources (“Framing the Problem”) into three column table (Title hyperlinked to source, Summary, and Perspective) and post

Hydrate Lab Write Up due next class (NOT a full write up). Science Research: Final Report due 12/11 (A Day) and 12/12 (B Day) No online submission Formal report or display board Boards on sale: $3 Science Fair: 12/14 after school, extra credit, write your name on the board Due by 12/15: Complete web 2.0 product (“Understanding the Problem”) and post Organize sources (“Framing the Problem”) into three column table (Title hyperlinked to source, Summary, and Perspective) and post Outcome: I can explain the effect of phosphate pollution on the Chesapeake Bay.

Drill 5: 12/6 (A Day) 12/7 (B Day)
Hand in the Hydrate Lab Write Up to the bin Write down your outcome and start CW 4 immediately. Outcome: I can write and balance chemical reactions.

CW 4: Balancing Chemical Equations
Indicate the reactants and products for each reaction in the table below: What does the arrow represent in a chemical reaction? “Yields” or “forms” Reaction Reactant(s) Product(s) (1) (2) I2(g) and H2(g) 2HI(g) 2CO(g) and O2(g) 2CO2(g)

For reaction (1), how many H atoms and I atoms are represented on: The reactant side? The product side? For reaction (2), how many C atoms and O atoms are represented on: What general statement can be made about the number of atoms of each type on the two sides of a chemical equation? The number of atoms on both sides of the arrow is the same. H: 2 H: 2 I: 2 I: 2 C: 2 C: 2 O: 4 O: 4

A balanced chemical reaction: Describes how many reactant molecules are consumed to produce a certain number product molecules. Describes how many moles of reactants are consumed to produce a certain number of moles of products. How many moles HI molecules are produced for every H2 molecule that is consumed in reaction (1)? 2 HI for 1 H2

For reaction (2): How many CO2 molecules are produced for every O2 molecule consumed? How many CO2 molecules are produced for every CO molecule consumed? How many moles of CO2 are produced when 2 moles of O2 are consumed? How many moles of CO2 are produced when 5 moles of O2 are consumed? 2 CO2 for 1 O2 2 molecules CO2 2 CO2 for 2 CO 1 molecules CO2 2 moles CO2 = 1 mole O2 4 moles CO2 2 moles CO2 = 1 mole O2 10 moles CO2

How many moles of I2 react in order to produce 12 moles of HI in reaction (1)? Explain your findings in the previous question with the idea that atoms are neither created nor destroyed when chemical reactions take place (Law of Conservation of Mass). Atoms react in certain ratios The number of atoms on each side is the same, if you double the reactant side, the product side is also doubled 2 HI for 1 I2 12 HI for 6 I2

Balance the following chemical equations. ___ SiC + ___ Cl2 → ___ SiCl4 + ___ C

Balance the following chemical equations. ___ KOH + ___ H2SO4 → ___ K2SO4 + ___ H2O

Balance the following chemical equations. ___ N2 + ___ O2 → ___ N2O

Balance the following chemical equations. ___ Li + ___Cl2 → ___LiCl

Balance the following chemical equations. ___ CaSO4 + ___ AlCl3  ___ Al2(SO4)3 + ___ CaCl2

CW 5: Writing Chemical Equations
Each reaction will be demonstrated to you; make note of the state of matter for all reactants and products. You need a table of elements; we will be writing formulas from names.

reactants products C8H18(l) + O2(g)  CO2(g) + H2O(g) + heat Indicates the state of matter: l – liquid g – gas s – solid aq – aqueous (dissolved in water) Energy can be a product OR reactant

Have No Fear Of Ice Cold Beer H2 N2 F2 O2 I2 Cl2 Br2 Hydrogen = H2, never H Nitrogen = N2, never N When by itself

Write the formula for each of the following, then use the solubility guidelines to determine if each compound would be aqueous or solid in solution. Sodium nitrate Silver chloride Barium sulfate Ammonium Carbonate aq s s aq

Magnesium burns in the presence of oxygen to form magnesium oxide. +2 -2 2 Mg + O2  2 Mg O (s) (g) (s)

An electric current is run along a wire submerged in water. Oxygen gas and hydrogen gas are formed. 2 H2O + energy  O2 + 2 H2 (l) (g) (g)

Hydrochloric acid reacts with magnesium metal, forming magnesium chloride and hydrogen gas. +1 -1 +2 -1 2 H Cl + Mg  Mg Cl + H2 (aq) (s) (aq) 2 (g) + heat

Hydrogen gas reacts explosively with oxygen gas to form water vapor. 2 H2 + O2  2 H2O + energy (g) (g) (g)

Copper (II) sulfate solution reacts with sodium hydroxide solution to form copper (II) hydroxide and sodium sulfate. +2 -2 +1 -1 Cu SO4 + 2 Na OH  (aq) (aq) +2 -1 +1 -2 Cu (OH) + Na SO4 2 (s) 2 (aq)

Acetic acid reacts with sodium hydrogen carbonate to form sodium acetate and carbonic acid. In a separate reaction the carbonic acid breaks down into carbon dioxide and water. +1 -1 +1 -1 H C2H3O2 + Na HCO3  (aq) (s) +1 -1 +1 -2 Na C2H3O2 + H CO3 (aq) 2 (aq) H2CO3  CO2 + H2O (aq) (g) (l)

HW 2: Chemical Equations I Unit 2 Test Redo Reteach 12/13 both blocks Retest 12/15 and 12/18 both blocks Science Research: Final Report due 12/11 (A Day) and 12/12 (B Day) No online submission Science Fair: 12/14 after school, extra credit, write your name, boards $3 Due by 12/15: Complete web 2.0 product (“Understanding the Problem”) and post Organize sources (“Framing the Problem”) into three column table (Title hyperlinked to source, Summary, and Perspective) and post Outcome: I can write and balance chemical reactions.

Drill 6: 12/11 (A Day) 12/12 (B Day)
Hand in Science Research Part 9 Write the equation and balance: Solid calcium carbonate breaks down when heated to form solid calcium oxide and carbon dioxide gas. Outcome: I can determine the type of reaction and predict if a single replacement reaction will occur.

CW 6: Types of Chemical Reactions
Combination General Equation R + S  RS Example 2Na + Cl2  2NaCl Reactants 2 elements, or 2 compounds Products A single compound

Decomposition General Equation RS  R + S Example 2HgO  2Hg + O2 Reactants A single compound Products 2 or more simpler products

Always reacts with O2 Combustion General Equation CxHyOz + O2  CO2 + H2O Example CH4 + 2O2  CO2 + 2H2O Reactants Hydrocarbon and oxygen Products Carbon dioxide and water

Only works if T is more reactive than R. Single Replacement General Equation T + RS  TS + R Example 2K + 2HOH  2KOH + H2 Reactants Lone element and an ionic compound Products New lone element and a new ionic compound

Double Replacement General Equation R+S- + T+U-  R+U- + T+S- Example 2KI + Pb(NO3)2  PbI2 + 2KNO3 Reactants 2 ionic compounds that switch cations. Products 2 new ionic compounds; driven by formation of a s, g, or H2O

CW 7: Single Replacement: Metal Activity Series
Sign on to laptops: groups of 2 Work on CW 7 questions 1 to 8 while the laptop loads Go to SRHSchem > Unit 3 and download the virtual lab under “other documents” Complete the chart and questions 9 to 11

What happens during a single replacement reaction and how can you identify one? A lone element “kicks out” an element from a compound. Both the reactants and products are a lone element and a compound 2K + 2HOH 2KOH + H2 Only works because K is more reactive than H! If this was not the case, no reaction would occur.

How does the activity series of metals relate to if a single replacement reaction will occur or not occur? T + RS  TS + R T can only replace R if T is higher (more reactive) on the activity series

Rank the halogens in order from most reactive to least reactive. Explain your ranking. F most reactive Nonmetals react by gaining electrons Cl Br Fewer layers of electrons = easier to gain electrons = more reactive I least reactive

Which is the most reactive metal? Magnesium – it replaces zinc, iron, and copper (most reactions) Which is the least reactive metal? Copper – cannot replace any metals (no reactions)

Put the four metals in order by reactivity. Compare the activity series you made in question 3 to the more complete activity series on the next page. Does it match up? Magnesium Zinc Iron Copper

Magnesium metal can be used to remove tarnish from silver items. Silver tarnish (Ag2S) is the corrosion that occurs when silver metal reacts with substances in the environment, especially those containing sulfur. Why would magnesium remove tarnish from silver? Mg is more reactive, so the tarnish forms on the Mg instead of the Ag. Use the activity series for metals to explain why copper metal is used in plumbing where the water might contain compounds of many different metals. Copper is low on the activity series, so it won’t react with most compounds dissolved in the water – copper pipes will stay intact.

Reactants Metal or Halogen? Does reaction occur? Mg(s) + LiNO3(aq) Metal NR: Mg is below Li on activity series, so it cannot replace Li. Cl2(g) + 2NaBr(aq) Halogen Reaction: Cl is more reactive than Br, meaning Cl will replace Br. Fe(s) + CuSO4(aq) Mg(s) + HCl(aq) Br2(g) + CaI2(aq) Ag(s) + CuCl2(aq) Metal Reaction: Fe is more reactive than Cu. Reaction: Mg is more reactive than H. Metal Halogen Reaction: Br is more reactive than I. Metal NR: Ag is less reactive than Cu.

Complete the virtual lab by accessing SRHSchem > unit 3 When done, check your answers with Ms. Leffel.

HW 3: Chemical Equations II Complete CW 6 and CW 7 if not done Unit 2 Test Redo Reteach 12/13 both blocks Retest 12/15 and 12/18 both blocks Science Research: Final Report due 12/11 (A Day) and 12/12 (B Day) No online submission Science Fair: 12/14 after school, extra credit, write your name, boards $3 Due by 12/15: Complete web 2.0 product (“Understanding the Problem”) and post Organize sources (“Framing the Problem”) into three column table (Title hyperlinked to source, Summary, and Perspective) and post Outcome: I can determine the type of reaction and predict if a single replacement reaction will occur.

Drill 7: 12/15 (A Day) 12/18 (B Day)
Based on the type of reaction, predict the products. Sulfuric acid reacts with sodium hydroxide. Outcome: I can write net ionic equations for chemical reactions.

CW 8: Keep Your Eye on the Ions
Draw a diagram of each of the following: The “compounds” Silver Nitrate (s) Sodium Chloride (s)

Draw a diagram of each of the following: The two beakers, after the compounds had been added and the solution formed Silver Nitrate (aq) Sodium Chloride (aq)

Draw a diagram of each of the following: After the solutions were combined Floating around in solution (aq) Silver Nitrate (s) Sodium Chloride (s) Sunk to the bottom (s)

Explain the chemical analogy behind what happens when the compounds are first added to water (picture 1b). The ions dissolving in the water When the solutions are combined, which of the colored ball(s) represents the precipitate? The ones which sunk to the bottom are solids – the yellow and orange compound

Aqueous Silver nitrate reacts with aqueous sodium chloride to form silver chloride and sodium nitrate. Write a balanced chemical equation for this reaction. Use your diagrams from above to determine which colored ball represented each of the following ions.

CW 9: Double Replacement Net Ionic Equations
AgNO3(aq) + NaCl(aq)  AgCl(s) + NaNO3(aq) This equation fails to show how this reaction occurs in aqueous solution – the ionic compounds dissociate into their cations and anions. Ag+(aq) + NO3-(aq) + Na+(aq) + Cl-(aq)  AgCl(s) + Na+(aq) + NO3-(aq) This is the complete ionic equation, with all ions written out. Ag+(aq) + Cl-(aq)  AgCl(s) The net ionic equation is created by simplifying the complete ionic equation, by removing the spectator ions (ions that are unchanged on both sides of the arrow)

For the following, cross out the spectator ions, then write the net ionic equation. Ni2+(aq) + 2NO3-(aq) + 2Na+(aq) + 2OH-(aq)  Ni(OH)2(s) + 2Na+(aq) + 2NO3-(aq) Fe(s) + Cu2+(aq) + 2NO3-(aq)  Fe2+(aq) + 2NO3-(aq) + Cu(s) Na+(aq) + NO3-(aq) + K+(aq) + Cl-(aq)  K+(aq) + NO3-(aq) + Na+(aq)+ Cl-(aq) Ni2+(aq) + 2OH-(aq)  Ni(OH)2(s) Fe(s) + Cu2+(aq)  Fe2+(aq) + Cu(s) All ions cancel = no reaction!

What unusual condition did you encounter in question 1c? All are spectator ions – all cancel out This is an example of a reaction that does not occur – the ions simply float around together in solution. Based on the reaction types shown in questions A to C, which type of reaction will you be required to write net ionic equations for? Single replacement Double replacement

Determine whether the following compounds are soluble (S) or insoluble (In) using the solubility rules. Calcium Carbonate Strontium hydroxide Calcium sulfate Potassium nitrate Iron (II) nitrate Lead (IV) carbonate In S In S S In

For each of the following double replacement reactions: Predict the products by swapping cations and balancing charges Determine if the products are soluble or insoluble Balance and include all state symbols Write the net ionic equation If there is no reaction (see question 2), write NR

+2 -1 +1 -2 ___Pb(NO3)2 (aq) + ___Na2SO4 (aq)  Net ionic equation: +1 -1 +2 -2 ___ 2 Na NO3 (aq) + ___ Pb SO4 (s) Pb+2(aq) + SO4-2(aq)  PbSO4(s)

+1 -1 +1 -1 ___NaClO3 (aq) + ___KCl (aq)  Net ionic equation: +1 -1 +1 -1 ___ Na Cl (aq) + ___ K ClO3 (aq) No reaction, all products are aqueous!

3 2 ___Ca(OH)2(aq) + ___H3PO4(aq)  ___H2O(l) + ___Ca3(PO4)2(s) Net ionic equation: HOH 6 3Ca+2(aq) + 6OH-1(aq) + 6H+1(aq) + 2PO4-3(aq)  6HOH(l) + Ca3(PO4)2(s) Nothing cancels out!

2 ___HCl(aq) + ___Na2S(aq)  ___H2S(g) + ___NaCl(aq) Net ionic equation: 2 2 H+1(aq) + S-2(aq)  H2S(g)

___HCl(aq) + ___NaHCO3(aq)  ___NaCl(aq) + ___H2O(l) + ___CO2(g) Net ionic equation: H+1(aq) + HCO3-2(aq)  H2O (l) + CO2(g)

HW 4: Chemical Equations III Complete CW 8 and CW 9 if not done Unit 2 Test Redo Reteach 12/13 both blocks Retest 12/15 and 12/18 both blocks Due by 12/15: Complete web 2.0 product (“Understanding the Problem”) and post Organize sources (“Framing the Problem”) into three column table (Title hyperlinked to source, Summary, and Perspective) and post Due by 12/18: Complete peer review of understanding the problem and framing the problem and send to peer group Outreach Program Proposal Outcome: I can write net ionic equations for chemical reactions.

Drill 8: 12/19 (A Day) 12/20 (B Day)
2A, B Day: Take out HW Prepare for quiz 3A, 4A: Take out CW 8 2A, 3A: Pick up the permission slips by the door and bring them in next time. Everyone: Have you completed and sent your peer reviews? Have you posted them? Outcome: I can identify 6 unknown solutions by testing their reactions.

CW 10: Chemystery Objective: Materials:
To identify six unknown solutions, each containing one substance dissolved in water. Materials: Transparency sheet with 6x6 matrix Unknown solutions Solubility chart/rules

CW 10: Chemystery Procedure:
Each group will receive six coded dropper bottles, each containing several milliliters of an aqueous solution of a single unknown substance. Each bottle will contain a different solution. The team will make observations on the individual solutions, and on drops mixed in pairs, in order to identify the substances. No substances other than the solutions in the bottles may be used. The possible substances are: HCl, NaOH, and soluble salts containing the ions Ba2+, CO32-, Cu2+, and Pb2+. A transparent plastic sheet matrix will be provided. For each solution, place a drop, mixing the solutions in pairs. The group must carry out all tests on the plastic sheet provided. Testing the solutions by touching is not allowed.

CW 10: Chemystery Cu(NO3)2 Conclusion
Identify each solution: Note: Each time you try to identify the solutions, you will receive points according to the following scheme: First try: 16 % for each correct identification Second try: 8 % for each correct identification Third try: 4 % for each correct identification Cu(NO3)2 NaOH Pb(NO3)2 HCl Na2CO3 Ba(NO3)2

CW 10: Chemystery Scaffold sheet Some hints:
Use the provided sheet (page 36) to predict the products and use the solubility rules to determine if the products are aqueous or solid Some hints: HCl and Na2CO3 make H2CO3, which produces bubbles – look for these two first Determine which is which by looking at each reaction and the predicted products Cu(NO3)2 NaOH Pb(NO3)2 HCl Na2CO3 Ba(NO3)2 NR

3A, 4A: HW 4: Chemical Equations III What should be done with the project: Understanding the problem + peer review posted Framing the problem + peer review posted Outreach program proposal posted Coming up: Peer review of out reach program, posted 12/20 Begin working on your outreach program Outcome: I can identify 6 unknown solutions by testing their reactions.

How can we predict the amounts of substances in a chemical reaction?

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