Tuesday, September 3, 2013

AP Chem Balanced Equations and Chemical Reactions

AP Chemistry

Equations and Balancing Equations

Homework and Discussions for the week of 3. 

1. Further Reading Into Chemical Equations   

2. Explanation by Kahn Academy, Balancing Equation 

3. Practice Game 

4.   Another Practice Game

Concepts to review and answer as you go through this material:

Reviewing Concepts

  1. Identify the reactants and products in each chemical reaction.
    1. In photosynthesis, carbon dioxide and water react to form glucose and oxygen.
    2. Magnesium oxide forms when magnesium is exposed to oxygen gas.
  2. What is the relationship between an equal sign and a yield sign?
  3. Write sentences that completely describe the chemical reactions shown in the skeleton equations below.
    1. \text{H}_2\text{O}_2(l) \overset{\text{MnO}_2}{\rightarrow} \text{H}_2\text{O}(l) + \text{O}_2(g)
    2. \text{CuCO}_3(s) \overset{\Delta}{\rightarrow} \text{CuO}(s) + \text{CO}_2(g)
    3. \text{Cs}(s) + \text{H}_2\text{O}(l) \rightarrow \text{CsOH}(aq) + \text{H}_2(g)
  4. How many atoms of each element are represented by the following combinations of coefficients and chemical formulas?
    1. 5Br2
    2. 2NH3
    3. 4(NH4)2SO4
    4. 2CH3COOH
    5. 3Fe(NO3)3
    6. 2K3PO4
  5. The skeleton equation for the reaction of nitrogen gas with oxygen gas to form dinitrogen monoxide is shown below. Explain why the equation below is not a correctly balanced equation for this reaction.

Problems

  1. Balance each of the following equations.
    1. KClO3 → KCl + O2
    2. Ca(OH)2 + HBr → CaBr2 + H2O
    3. C4H10 + O2 → CO2 + H2O
    4. NH3 + CuO → Cu + N2 + H2O
  2. Write and balance chemical equations for each of the following word equations.
    1. sodium carbonate → sodium oxide + carbon dioxide
    2. tetraphosphorus decoxide + water → phosphoric acid
    3. lead + nitrogen → lead(II) nitride
    4. ammonium carbonate → ammonia + water + carbon dioxide
  3. Write and balance chemical equations from the following descriptions. Include symbols for the physical states of each reaction component.
    1. Solid barium oxide is reacted with water and forms aqueous barium hydroxide.
    2. Aqueous lithium phosphate reacts with aqueous iron(III) nitrate to form aqueous lithium nitrate and solid iron(III) phosphate.
    3. Aluminum metal is reacted with an aqueous solution of zinc chloride to form aqueous aluminum chloride and solid zinc.
    4. Iron(III) oxide solid reacts with carbon monoxide gas to produce iron and carbon dioxide gas.
  4. The following equations are incorrect in some way. Identify and correct each error, and then balance the corrected equation.
    1. K + O2 → KO2
    2. Ag2O → Ag2 + O
    3. NaCl + F2 → NaF2 + Cl 


    Reviewing Concepts

  5. Write a general reaction for each reaction type below.
    1. double-replacement
    2. decomposition
    3. single-replacement
    4. combination
  6. Which type of reaction generally takes place only between substances in aqueous solution?
  7. What do all combustion reactions have in common?
  8. Where on an activity series are the most reactive elements located?
  9. Classify the following reactions according to the five basic reaction types.
    1. Cd(s) + H2SO4(aq) → CdSO4(aq) + H2(g)
    2. 2Fe(s) + 3Cl2(g) → 2FeCl3(s)
    3. C7H8(l) + 9O2(g) → 7CO2(g) + 4H2O(g)
    4. 2NH4NO3(s) → 2N2(g) + O2(g) + 4H2O(g)
    5. 2CoCl3(aq) + 3Pb(NO3)2(aq) → 2Co(NO3)3(aq) + 3PbCl2(s)

Problems

15. Write balanced chemical equations for the following combination reactions.
    1. Sr(s) + S(s) →
    2. Zn(s) + O2(g) →
    3. Li2O(s) + H2O(l) →
  1. Write balanced chemical equations for the following decomposition reactions.
    1. \text{Na}_3\text{N}(s) \overset{\Delta}{\rightarrow}
    2. \text{SnCO}_3(s) \overset{\Delta}{\rightarrow}
    3. \text{NCl}_3(l) \rightarrow
    4. \text{Mg(OH)}_2(s) \overset{\Delta}{\rightarrow}
  2. Use the activity series to write a balanced chemical equation for the following single-replacement reactions. Write NR if no reaction occurs.
    1. Cl2(g) + NaF(aq) →
    2. Ca(s) + H2O(l) →
    3. Pt(s) + H2SO4(aq) →
    4. Al(s) + NiBr2(aq) →
  3. Write balanced chemical equations for the following double-replacement reactions.
    1. Ca(NO3)2(aq) + K3PO4(aq) → (calcium phosphate precipitates)
    2. HI(aq) + Mg(OH)2(aq) →
    3. FeS(s) + HCl(aq) → (aqueous iron(II) chloride is one product)
    4. CuBr2(aq) + KOH(aq) → (copper(II) hydroxide precipitates)
    5. 20.Write balanced equations for the combustion of the following compounds.
    1. ethyne (C2H2)
    2. acetic acid (CH3COOH)
    3. hexane (C6H14)

Monday, April 29, 2013

What would an Ideal School Look Like?: 


Inspired by Rethinking High School – by Daniels, Bizar, & Zemelman 2000
 

From a kid’s-eye view, looked at as a place where a young person might grow and develop, they are usually boring, frequently a waste of time – and sometimes a danger. We are brought to the sad but inevitable conclusion: America’s high schools are failing all of our kids some of the time and some of our kids all of the time.”

The ideas in this book remind me of what Lorraine Monroe described in her book, Nothing’s Impossible, where she wrote about how her and a few other “crazy and creative” teachers would ponder what they would do if they got to start their own school or if they got to run one themselves. This is something that still drives me to this day, "what if?" I am still working on developing my own “Best Practice High School” that I want to take to the neighborhood where I started my teaching career and one that captured my heart – the Fountain Square Neighborhood.

Even in our better urban public schools, they are afflicted by the ails of violence, high mobility, low engagement, and a lack of success on standardized testing due to the lack of essential, basic skills of the students. What if we could be one of those insane educators-turned-entrepreneurs? What if we could take the chance to make a positive change in American education, especially for those who have been under served and under motivated? That is something I have been working toward doing and something that the authors of this book has done. In the process, they took a chance and come up with a school with a very (horrible) suitable name.

Formulating a Great Curriculum:
Part of what the school curriculum and purpose was based on was the call for a kind of learning depicted in the national curriculum standards: Student Centered; Experiential; Holistic; Authentic; Expressive; Reflective; Social; Collaborative; Democratic; Cognitive; Developmental; Constructivist; & Challenging. The application of these ideals is in the research and models that make up any great school. The founders of Best Practice looked for ways to implement these ideals and found some help in the guiding principles as laid out by the Coalition of Essential Schools and their view of the purpose of schools: Intellectual development; studying a few subjects deeply; high expectations; personalized learning environments; students involved in constructing meaning; Teachers acting as coaches and guides; students ability not test scores; families are essential to school life; teach kids not subjects; schools as model democracies; schools may need to omit some other functions to obtain these goals. 

We could all learn from these dreamers and think, "What if?"