Chapter 15 Holt

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Chapter 15 Holt

• Chemical Reactions

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Using Vocabulary

• 1. Adding a(n) inhibitor will slow down a
  chemical reactions.
• 2. A chemical reaction that gives off light is
  called exothermic.

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• 3. A chemical reaction that forms one compound
  from two or more substances is called a synthesis
  reaction.

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• 4. The 2 in the formula Ag2S is a subscript.
• 5. The staring materials in a chemical reaction
  are reactants.

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Understanding Concepts

• 6. Balancing a chemical equation so that the same
  number of atoms of each element is found in both
  the reactants and the products is an illustration
  of
• C) the law of conservations of mass.

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• 7. What is the correct chemical formula for
  calcium chloride?
• B) CaCl2
• Ca has a valence of 2, so 2 charge
• Cl has a valence of 7, so -1 charge
• So 2 Cl- with Ca makes CaCl2

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• 8. In which type of reaction do ions in two
  compounds switch places?
• D) double-replacement
• Ex NaOH HCl --gt NaCl H2O

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• 9. Which is an example of the use of activation
  energy?
• C) holding a match to paper

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• 10. Enzymes in your body act as catalysts. The
  role of enzymes is to
• A) Increase the rate of chemical reactions (make
  the reactions happen faster)

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Short Answers

• 11. Classify each of the following reactions
• A) Fe O2 --gt Fe2O3 synthesis
• Balanced this would be
• 4Fe 3O2 --gt 2Fe2O3
• Iron oxygen --gt rust

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• B) Al CuSO4 --gt Al2(SO4)3 Cu
• single replacement
• Balanced this is
• 2Al 3CuSO4 --gt Al2(SO4)3 3Cu
• Aluminum cupric sulfide --gt aluminum sulfide
  plus copper

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• C) Ba(CN)2 H2SO4 --gt BaSO4 HCN
• Double replacement
• Balanced this is
• Ba(CN)2 H2SO4 --gt BaSO4 2HCN

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• 12. Name two ways that you could increase the
  rate of a chemical reaction.
• 1) raise the temperature
• ( this increases the concentration and/or the
  surface area)
• 2) add a catalyst

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• 13. The reactants are acetic acid (vinegar) and
  baking soda (sodium bicarbonate).
• The products are carbon dioxide CO2 , water H2O,
  and sodium acetate.

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• 14. Concept map is on the white board.
• Terms are
• Chemical reaction
• Chemical equation
• Chemical formulas
• Reactants, products,
• Coefficients, subscripts

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Critical Thinking Problem Solving

• 15. Your friend is very worried by rumors he has
  heard about a substance called dihydrogen
  monoxide. What could you say to your friend to
  calm his fears?
• Dihydrogen H2
• Monoxide O
• So H2O - not to worry - its water !

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• 16. As long as proper safety precautions have
  been taken, why can explosives be transported
  long distances without exploding?
• Explosives need to absorb energy to being the
  reaction. Without this absorption, they can be
  transported safely.

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Math in Science

• 17. Calculate the number of atoms of each
  element shown in each of the following
• A) CaSO4
• Ca - Calcium - 1 atom
• S - Sulfur - 1 atom
• O - Oxygen - 4 atoms

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• B) 4NaOCl
• Na - sodium - 4 atoms
• O - oxygen - 4 atoms
• Cl - chlorine - 4 atoms

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• C) Fe(NO3)2
• Fe - iron - 1 atom
• N - nitrogen - 2 atoms
• O - oxygen - 6 atoms

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• D) 2Al2(CO3)3
• Al - Aluminum - 4 atoms
• C - carbon - 6 atoms
• O - oxygen - 18 atoms

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• 18. Write balanced equations for the following
• A) Fe O2 --gt Fe2O3

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• 18. Write balanced equations for the following
• A) Fe O2 --gt Fe2O3
• Answer
• 4Fe 3O2 --gt 2 Fe2O3

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• B) Al CuSO4 --gt Al2(SO4)3 Cu
• Answer

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• B) Al CuSO4 --gt Al2(SO4)3 Cu
• Answer
• 2Al 3CuSO4 --gt Al2(SO4)3 3Cu

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• C)
• Ba(CN)2 H2SO4 --gt BaSO4 HCN

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• C)
• Ba(CN)2 H2SO4 --gt BaSO4 HCN
• Answer
• Ba(CN)2 H2SO4 --gt BaSO4 2HCN

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• 19) Balanced chemical equations
• A) bromine reacts with sodium iodide to form
  iodine and sodium bromide
• Br2 2NaI --gt I2 2NaBr

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• B) Phosphorus reacts with oxygen gas to form
  diphosphorus pentoxide
• 4P 5O2 --gt 2P2O5

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• C) Lithium oxide decomposes to form lithium and
  oxygen
• 2Li2O --gt 4Li O2

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Interpreting Graphics

• 20. In the photo on page 393, what evidence
  supports that this is a chemical reaction?
• Answer
• - Bubbles of gas are produced
• - Light is given off

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• 21. Using the energy diagram on page 393, answer
  qs a,b,c
• A) C represents the energy of the products (far
  right section of graph)
• B) B represents the activation energy of the
  reaction (increases then peaks)
• C) Energy is given off by this reaction.
• Thats the decline of energy below starting
  energy mark - D on the chart)