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QR Challenge: Chemical Formulas and Reactions

Created using the ClassTools QR Treasure Hunt Generator

Teacher Notes

A. Prior to the lesson:

1. Arrange students into groups. Each group needs at least ONE person who has a mobile device.

2. If their phone camera doesn't automatically detect and decode QR codes, ask students to

3. Print out the QR codes.

4. Cut them out and place them around your class / school.


B. The lesson:

1. Give each group a clipboard and a piece of paper so they can write down the decoded questions and their answers to them.

2. Explain to the students that the codes are hidden around the school. Each team will get ONE point for each question they correctly decode and copy down onto their sheet, and a further TWO points if they can then provide the correct answer and write this down underneath the question.

3. Away they go! The winner is the first team to return with the most correct answers in the time available. This could be within a lesson, or during a lunchbreak, or even over several days!


C. TIPS / OTHER IDEAS

4. A detailed case study in how to set up a successful QR Scavenger Hunt using this tool can be found here.


Questions / Answers (teacher reference)

Question

Answer

1. 1. Why should a chemical equation be balanced?See answer key
2. 2. Why are decomposition reactions called the opposite of combination reactions?See answer key
3. 3. What do you think the subscripts in the chemical formulas represent?See answer key
4. 4. How many of a particular atom are present in a compound when there is no subscript written?See answer key
5. 5. What is added to the formula to indicate that more than one copy of a group of atoms is present in a compound?See answer key
6. 6. How is the number of atom groups indicated in the formula when parentheses are present?See answer key
7. 7. Compare the charges on the polyatomic ions. Are the majority of the charges positive or negative?See answer key
8. 8. Which polyatomic ion is positively charged? (Write the name and the formula)See answer key
9. 9. Where are the negatively charged polyatomic ions located in compound formulas – at the beginning or the end of the compound?See answer key
10. 10. Where are the positively charged polyatomic ions located in the compound formulas – at the beginning or the end of the compound?See answer key
11. 11. Do the names of the metal elements change when they are written in compound names? If yes, how do they change?See answer key
12. 12. Do the names of the nonmetal elements change when they are written in compound names? If yes, how do they change?See answer key
13. 13. Do the names of the polyatomic ions change when they are written in compound names? If yes, how do they change?See answer key
14. 14. What do you think the Roman Numerals in compound names represent?See answer key
15. 15. A substance that enters into a chemical reaction is called a:see answer key
16. 16. The word equation “magnesium reacts with chlorine to produce magnesium chloride” would be represented by which formula equation?answer key
17. 17. In a chemical equation, the number of molecules of a given substance is indicated by a:answer key
18. 18. Which of the following symbols means a substance is in a water solution – (s), (aq), (w), (l)?answer key
19. 19. What is the general form for a single-replacement reaction (i.e. A + B ---> C)answer key
20. 20. What is the general form for a double-replacement reaction (i.e. A + B ---> C)answer key
21. 21. A solid produced by a chemical reaction in solution that separates from the solution is called?answer key
22. 22. The reaction 2Mg(s) + O2(g) ---> 2MgO(s) is what type of reaction: synthesis, decomposition, single replacement, double replacement, neutralization?answer key
23. 23. The reaction Mg(s) + HCl(aq) ---> MgCl2(aq) + H2(g) is what type of reaction: synthesis, decomposition, single replacement, double replacement, neutralization?answer key
24. 24. The reaction CaCO3(s) ---> CaO(s) + CO2(g) is what type of reaction: synthesis, decomposition, single replacement, double replacement, neutralization?answer key
25. 25. The reaction Pb(NO3)2(aq) + 2KI(aq) ---> PbI2(s) + 2KNO3(aq) is what type of reaction: synthesis, decomposition, single replacement, double replacement, neutralization?answer key
26. 26. What type of ion gains electrons and has a negative charge?answer key
27. 27. What type of bond involves a sharing of valence electrons?answer key
28. 28. What is the correct chemical formula and name when a calcium ion transfers electrons with a nitrate polyatomic ion to form a compound?answer key
29. 29. Molar mass is measured using units of _________.answer key
30. 30. Susan collects an actual mass of 5.30 g of product, compared to 6.04 g that should have been collected. Based on her calculations, what is the percent error?answer key
31. 31. What percent of carbon monoxide is oxygen?answer key
32. 32. Some underwater welding is done via the thermite reaction, in which rust (Fe2O3) reacts with aluminum to produce iron and aluminum oxide (Al2O3). In one such reaction, 258 g of aluminum and excess rust produced 464 g of iron. What was the percent yield of this reaction?answer key
33. 33. In a reaction where potassium chlorate decomposes into potassium chloride and oxygen gas, how many grams of potassium chloride is produced if 2.50 g of potassium chlorate is decomposed?answer key
34. 34. In a reaction where potassium chlorate decomposes into potassium chloride and oxygen gas, how many liters of O2 is produced if 5.00 moles of potassium chlorate is used?answer key
35. 35. Given the balanced equation: 2N2H4(l) + N2O4(l)  3N2(g) + 4H2O(g), how many moles of dinitrogen tetrahydride are required to produce 57 moles of nitrogen? How many moles of dinitrogen tetroxide are required to produce 57 moles of nitrogen?answer key
36. 36. Camels store the fat tristearin (C57H110O6) in the hump. As well as being a source of energy, the fat is a source of water, because when it is used the (unbalanced) reaction: C57H110O6 (s) + O2(g) ---> CO2(g) + H2O(l) takes place. At STP, what volume of oxygen is required to consume 0.64 moles of tristearin? If 22.4 L of oxygen is consumed at STP, how many moles of water are produced? Find the mass of tristearin required to produce 55.56 moles of water?answer key
37. 37. How many moles are there in 458 grams of Na2SO4?answer key
38. 38. How many grams are there in 7.40 moles of silver nitrate?answer key
39. 39. How many molecules are there in 2.30 g of NH3 (ammonia)?answer key
40. 40. Chlorobenzene (C6H5Cl) is used in the production of various chemicals such as insecticides and dyes. One way that chlorobenzene is prepared is by reacting benzene (C6H6) with chlorine gas according to the following BALANCED equation: C6H6(l) + Cl2(g) ---> C6H5Cl(s) + HCl(g). What is the theoretical yield if 45.6 g of benzene react? If the actual yield is 63.7 g of chlorobenzene, calculate the percent yield.answer key

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q1/40:

1. Why should a chemical equation be balanced?&choe=UTF-8

Question 1 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q2/40:

2. Why are decomposition reactions called the opposite of combination reactions?&choe=UTF-8

Question 2 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q3/40:

3. What do you think the subscripts in the chemical formulas represent?&choe=UTF-8

Question 3 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q4/40:

4. How many of a particular atom are present in a compound when there is no subscript written?&choe=UTF-8

Question 4 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q5/40:

5. What is added to the formula to indicate that more than one copy of a group of atoms is present in a compound?&choe=UTF-8

Question 5 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q6/40:

6. How is the number of atom groups indicated in the formula when parentheses are present?&choe=UTF-8

Question 6 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q7/40:

7. Compare the charges on the polyatomic ions. Are the majority of the charges positive or negative?&choe=UTF-8

Question 7 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q8/40:

8. Which polyatomic ion is positively charged? (Write the name and the formula)&choe=UTF-8

Question 8 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q9/40:

9. Where are the negatively charged polyatomic ions located in compound formulas – at the beginning or the end of the compound?&choe=UTF-8

Question 9 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q10/40:

10. Where are the positively charged polyatomic ions located in the compound formulas – at the beginning or the end of the compound?&choe=UTF-8

Question 10 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q11/40:

11. Do the names of the metal elements change when they are written in compound names? If yes, how do they change?&choe=UTF-8

Question 11 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q12/40:

12. Do the names of the nonmetal elements change when they are written in compound names? If yes, how do they change?&choe=UTF-8

Question 12 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q13/40:

13. Do the names of the polyatomic ions change when they are written in compound names? If yes, how do they change?&choe=UTF-8

Question 13 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q14/40:

14. What do you think the Roman Numerals in compound names represent?&choe=UTF-8

Question 14 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q15/40:

15. A substance that enters into a chemical reaction is called a:&choe=UTF-8

Question 15 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q16/40:

16. The word equation “magnesium reacts with chlorine to produce magnesium chloride” would be represented by which formula equation?&choe=UTF-8

Question 16 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q17/40:

17. In a chemical equation, the number of molecules of a given substance is indicated by a:&choe=UTF-8

Question 17 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q18/40:

18. Which of the following symbols means a substance is in a water solution – (s), (aq), (w), (l)?&choe=UTF-8

Question 18 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q19/40:

19. What is the general form for a single-replacement reaction (i.e. A + B ---> C)&choe=UTF-8

Question 19 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q20/40:

20. What is the general form for a double-replacement reaction (i.e. A + B ---> C)&choe=UTF-8

Question 20 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q21/40:

21. A solid produced by a chemical reaction in solution that separates from the solution is called?&choe=UTF-8

Question 21 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q22/40:

22. The reaction 2Mg(s) + O2(g) ---> 2MgO(s) is what type of reaction: synthesis, decomposition, single replacement, double replacement, neutralization?&choe=UTF-8

Question 22 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q23/40:

23. The reaction Mg(s) + HCl(aq) ---> MgCl2(aq) + H2(g) is what type of reaction: synthesis, decomposition, single replacement, double replacement, neutralization?&choe=UTF-8

Question 23 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q24/40:

24. The reaction CaCO3(s) ---> CaO(s) + CO2(g) is what type of reaction: synthesis, decomposition, single replacement, double replacement, neutralization?&choe=UTF-8

Question 24 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q25/40:

25. The reaction Pb(NO3)2(aq) + 2KI(aq) ---> PbI2(s) + 2KNO3(aq) is what type of reaction: synthesis, decomposition, single replacement, double replacement, neutralization?&choe=UTF-8

Question 25 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q26/40:

26. What type of ion gains electrons and has a negative charge?&choe=UTF-8

Question 26 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q27/40:

27. What type of bond involves a sharing of valence electrons?&choe=UTF-8

Question 27 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q28/40:

28. What is the correct chemical formula and name when a calcium ion transfers electrons with a nitrate polyatomic ion to form a compound?&choe=UTF-8

Question 28 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q29/40:

29. Molar mass is measured using units of _________.&choe=UTF-8

Question 29 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q30/40:

30. Susan collects an actual mass of 5.30 g of product, compared to 6.04 g that should have been collected. Based on her calculations, what is the percent error?&choe=UTF-8

Question 30 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q31/40:

31. What percent of carbon monoxide is oxygen?&choe=UTF-8

Question 31 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q32/40:

32. Some underwater welding is done via the thermite reaction, in which rust (Fe2O3) reacts with aluminum to produce iron and aluminum oxide (Al2O3). In one such reaction, 258 g of aluminum and excess rust produced 464 g of iron. What was the percent yield of this reaction?&choe=UTF-8

Question 32 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q33/40:

33. In a reaction where potassium chlorate decomposes into potassium chloride and oxygen gas, how many grams of potassium chloride is produced if 2.50 g of potassium chlorate is decomposed?&choe=UTF-8

Question 33 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q34/40:

34. In a reaction where potassium chlorate decomposes into potassium chloride and oxygen gas, how many liters of O2 is produced if 5.00 moles of potassium chlorate is used?&choe=UTF-8

Question 34 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q35/40:

35. Given the balanced equation: 2N2H4(l) + N2O4(l)  3N2(g) + 4H2O(g), how many moles of dinitrogen tetrahydride are required to produce 57 moles of nitrogen? How many moles of dinitrogen tetroxide are required to produce 57 moles of nitrogen?&choe=UTF-8

Question 35 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q36/40:

36. Camels store the fat tristearin (C57H110O6) in the hump. As well as being a source of energy, the fat is a source of water, because when it is used the (unbalanced) reaction: C57H110O6 (s) + O2(g) ---> CO2(g) + H2O(l) takes place. At STP, what volume of oxygen is required to consume 0.64 moles of tristearin? If 22.4 L of oxygen is consumed at STP, how many moles of water are produced? Find the mass of tristearin required to produce 55.56 moles of water?&choe=UTF-8

Question 36 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q37/40:

37. How many moles are there in 458 grams of Na2SO4?&choe=UTF-8

Question 37 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q38/40:

38. How many grams are there in 7.40 moles of silver nitrate?&choe=UTF-8

Question 38 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q39/40:

39. How many molecules are there in 2.30 g of NH3 (ammonia)?&choe=UTF-8

Question 39 (of 40)

 



Chemical Formulas and Reactions: QR Challenge

https://www.classtools.net/QR/decode.php?text=Chemical Formulas and Reactions
Q40/40:

40. Chlorobenzene (C6H5Cl) is used in the production of various chemicals such as insecticides and dyes. One way that chlorobenzene is prepared is by reacting benzene (C6H6) with chlorine gas according to the following BALANCED equation: C6H6(l) + Cl2(g) ---> C6H5Cl(s) + HCl(g). What is the theoretical yield if 45.6 g of benzene react? If the actual yield is 63.7 g of chlorobenzene, calculate the percent yield.&choe=UTF-8

Question 40 (of 40)