Chemical Reactions Review :

1. Chemical Reactions Review: Jeopardy Game

2. Team Scores Team MVP Participant Scores Conserv. Of Mass Chemical Formulas Pictures Indicators Reactions Balanced? $100 $100 $100 $100 $100 $100 $200 $200 $200 $200 $200 $200 $300 $300 $300 $300 $300 $300 $400 $400 $400 $400 $400 $400 $500 $500 $500 $500 $500 $500

3. Chemical Formulas $100 Which information could a student determine from only the chemical formula of a protein? • The color of the protein • The number of molecules in each sequence that makes up the protein • The physical arrangement of atoms in the structure of the protein • The number of atoms of each element in the protein

4. Chemical Formulas $200 P4 + 3O2 2 P2O3In the equation above, how many atoms of phosphorus are there in the product? • 2 • 4 • 5 • 6

5. Chemical Formulas $300 A subscript in a chemical formula tells you _____ • How many total atoms of all kinds are in the compound • How many different elements there are in the compound • How many atoms of a certain kind are in the compound • What the symbol is for a particular element

6. Chemical Formulas $400 How many total atoms are there in the compound C8H9NO2 • 4 • 5 • 19 • 20

7. Chemical Formulas $500 Which of the following compounds has the greatest number of elements? • C2H6 • CH4 • NaBr • HNO2

8. Indicators $100 Your grandmother’s silver necklace turned black over the years. Soap and water will not clean it, but you can rub off the blackened material on the necklace. What is the explanation for the blackened material on the necklace? • Soil and oil from the wearer’s neck darkened the necklace • A physical change, called rusting, occurred between the silver and air • A chemical reaction, called tarnishing, occurred between the silver and air • Storing the necklace in a dark jewelry box changed the necklace

9. Indicators $200 Mike did a science experiment for a class project. He placed a white egg into a tall glass vase full of red wine vinegar. Mike described his observations to the class during the experiment. Which of these observations most clearly tells Mike that a chemical change occurred? • When the egg was added to the vinegar, the egg’s shell turned light red • During the experiment, the egg slowly rose to the surface of the vase • The vinegar smelled strong when the top was taken off the bottle • Lots of little bubbles appeared on the egg and fizzed to the surface of the vinegar

10. Indicators $300 A student observes some sugar as it is heated and burns. Which observation about the burning sugar provides evidence that a chemical reaction has occurred? • The sugar turns black and a gas is produced • The sugar melts and becomes a liquid • The temperature of the sugar increases • The sugar is white and smells sweet

11. Indicators $400 The pictures below show a blue liquid being added to a clear liquid. Which is the best evidence that a chemical reaction may have occurred. • The solution turned light blue • A precipitate has formed • The temperature remained the same • The volume increased

12. Indicators $500 Scientists spilled a solution on a lab table. They sprinkled baking soda on the spill to clean it up. Which observation would provide the best evidence that a chemical reaction occurred? • The hydrochloric acid evaporated, leaving only the baking soda • Some of the baking soda dissolved in the hydrochloric acid • The baking soda and hydrochloric acid combined and bubbles formed • The baking soda absorbed the hydrochloric acid

13. Reactions $100 According to this equation, what happened to the carbon and oxygen? • They combined chemically to form carbon and oxygen • They combined chemically to form a new compound • They combined physically to form a new mixture • They combined physically to form a new element

14. Reactions $2000 What does the number 3 in 3H2Otell you?WO3 + 3H2 → W + 3H2O • The reaction produces 3 water molecules • The reaction produces 3 atoms of water • The reaction produces 3 atoms of hydrogen • The reaction produces 6 water molecules

15. Reactions $300 It is important to write chemical formulas properly to show what is happening in a reaction. Which of the following is true of the equation below?CaCO3 + 2HCl  CaCl2 + H2CO3 • The 2 after the CaCl indicates 2 molecules of CaCl • The 2 before the HCl indicates 2 molecules of HCl • The 3 after the CaCO indicates 3 atoms of CO • The 3 after the H2CO indicates 3 molecules of CO

16. Reactions $400 What are the reactants in the formula that produces rust?4 Fe + 3O2→ 2Fe2O3 • Fe2O3 • Fe • Fe, O2 • Fe, 3O2, Fe2O3

17. Reactions $500 Which of the following distinguishes a chemical reaction from a physical change? • The chemical reaction is reversible • The properties of the reactants are the same as the products • The mass of the reactants is different from the mass of the products • A new substance must be created in a chemical reaction

18. Balanced? $100 Which of the following chemical equations is balanced? • 2HCl + NaOH → H2O + NaCl • P4O10 + H2O → 3H3PO4 • CH4 + 2O2 → 2H2O + CO2 • Fe2O3 + 2C → 2Fe + CO2

19. Balanced? $200 Why isn’t the following chemical equation balanced?C3H8 + 02→ 3CO2 + 4H2O • H2O is not on both sides of the equation • The number of oxygen atoms is not equal on both sides of the equation • The number of hydrogen atoms is not equal on both sides of the equation • The number of carbon atoms is not equal on both sides of the equation

20. Balanced? $300 A student passes an electric current through melted calcium chloride (CaCl2) producing pure calcium metal (Ca) and chlorine gas (Cl2). What is the balanced equation for this reaction? • 2CaCl2→ Ca + 2Cl2 • Ca + Cl2→ CaCl2 + Cl • Ca + CaCl2→ 2Ca + 2Cl2 • CaCl2→ Ca + Cl2

21. Balanced? $400 All of the following chemical equations are balanced except _____ • C3H8 + 502→ 3CO2 + 4H2O • Ca + CaCl2→ 2Ca + 2Cl2 • CH4 + 2O2 → 2H2O + CO2 • Cl2 + 2NaBr → 2NaCl + Br2

22. Balanced? $500 Is the equation below balanced? • Yes, because there are two reactants and two products • No, there are too many carbon atoms on the reactant side • Yes, because there are three elements on both sides of the equation • No, there are not enough carbon atoms on the reactant side

23. Conservation of Mass $100 Which of the following is a balanced equation? • Cl2 + NaBr 2NaCl + Br2 • Cl2 + 2NaBr 2NaCl + Br2 • Cl2+ 2NaBr 2NaCl + 2Br2 • 2Cl2+ NaBr 2NaCl + 2Br2

24. Conservation of Mass $200 Which equation shows that the total mass during a chemical reaction stays the same? • 1 • 2 • 3 • 4

25. Conservation of Mass $300 The table below shows a chemical equation. What is the mass of the water produced? • 112.5 g • 50 g • 200 g • 250.5 g

26. Conservation of Mass $400 What does it mean for a chemical equation to be balanced? • There are the same number of atoms of each element on both sides of the equation • The reactants and the products are written with the same coefficients • The number of reactants is equal to the number of products • The solid products weigh the same as the reactants

27. Conservation of Mass $500 Chemical equations must be balanced. This diagram shows that ___ • The atoms on the reactants side are changed into different atoms on the products side • The number of molecules on the reactants side is the same as the number of molecules on the products side • The number of atoms in the reactants is equal to the number of atoms in the product • The reactants are the same substances as the products

28. Pictures $100 What is the best chemical formula for the substance below? • Fe2 + O4 • 2FeO • 3FeO4 • Fe3O4

29. Pictures $200 The methane molecule below contains _____ • One atom • Two elements • Two compounds • Five elements

30. Pictures $300 Which chemical formula matches the molecule below? • CH5N • 2CH3N • CH5N2 • CH6N

31. Pictures $400 Is the following equation balanced? • Yes • No • Almost

32. Pictures $500 What is the indicator that shows milk has gone through a chemical change • Light produced • Gas produced • Precipitate produced • Temperature change