For each chemical reaction or physical change, record your observations (i.e. co

Question

For each chemical reaction or physical change, record your observations (i.e. color changes, a ppt or solid formation, gas bubbles/odors, heat production, etc.). Observations should be detailed descriptions of WHAT you see, hear, smell, and feel. Recording a (+/–) is NOT an observation!

Short Answers:

1. Zn/HCl (single displacement) OBSERVATIONS:

2. NaHCO3/HCl (double displacement) OBSERVATIONS:

3. Sugar (C12H22O11) (decomposition) OBSERVATIONS:

4.CuSO4•5H2O (decomposition) OBSERVATIONS:

5. Fe/CuSO4 (single displacement) OBSERVATIONS:

6. NH3/HCl (combination) OBSERVATIONS:

7. Cu/HCl and Al/HCl (single displacement) OBSERVATIONS (for BOTH):

8. K2SO4/Ba(NO3)2 (double displacement) OBSERVATIONS:

9. NaOH/HCl (double displacement) OBSERVATIONS:

QUESTIONS:

1. Which procedure(s) [#1 – #9] were NOT chemical reaction(s) as predicted above (there are two!)? How were you able to determine this (i.e. one is a physical change and one procedure did not react = no reaction)?

2. Which procedure(s) [#1 – #9] produced water(g) vapor (there are two possibilities!)? Which procedure resulted in a physical change?

3. Which procedure(s) [#1 – #9] produced a gas other than water(g) vapor (there are three!)?

4. Which procedure(s) [#1 – #9] produced a solid from two non-solids (there are two!)?

5. Which procedure(s) [#1 – #9] produced heat (there is one!)?

6. Which procedure(s) [#1 – #9] produced copper metal (there is one!)?

7. What is the difference between the denotations (aq) and (l)? Give a specific example of each one.

Explanation / Answer

1. Zn/HCl (single displacement) OBSERVATIONS: gas formation

2. NaHCO3/HCl (double displacement) OBSERVATIONS: bubble formation

3. Sugar (C12H22O11) (decomposition) OBSERVATIONS: solid formation, change color

4.CuSO4•5H2O (decomposition) OBSERVATIONS: Change color

5. Fe/CuSO4 (single displacement) OBSERVATIONS: Change color

6. NH3/HCl (combination) OBSERVATIONS: Solid formation

7. Cu/HCl and Al/HCl (single displacement) OBSERVATIONS (for BOTH): Cu/HCl – No reaction, Al/HCl – gas formation

8. K2SO4/Ba(NO3)2 (double displacement) OBSERVATIONS: solid formation

9. NaOH/HCl (double displacement) OBSERVATIONS: Change color

QUESTIONS:

1. Which procedure(s) [#1 – #9] were NOT chemical reaction(s) as predicted above (there are two!)? How were you able to determine this (i.e. one is a physical change and one procedure did not react = no reaction)?

Physical Change: Number 4 – After heating the water evaporates and the CuSO4•5H2O (blue) becomes only CuSO4 (white). No reaction: Number 7 – Cu/HCl

2. Which procedure(s) [#1 – #9] produced water(g) vapor (there are two possibilities!)? Which procedure resulted in a physical change?

Number 3 and Number 4 (Number 4 is a Physical Change)

3. Which procedure(s) [#1 – #9] produced a gas other than water(g) vapor (there are three!)?

Number 1 (H2), Number 2 (CO2) and Number 7 (Al/HCl produces H2)

4. Which procedure(s) [#1 – #9] produced a solid from two non-solids (there are two!)?

Number 8 (BaSO4)

5. Which procedure(s) [#1 – #9] produced heat (there is one!)?

Number 9

6. Which procedure(s) [#1 – #9] produced copper metal (there is one!)?

Number 5

7. What is the difference between the denotations (aq) and (l)? Give a specific example of each one.

A liquid is a pure substance so it does not change its molar concentration in a reaction. (Number 2 – It forms H2O that is liquid). An aqueous solution is a substance that has been dissolved in a liquid so it has been dissociated into its positive and negative ions (Number 9 – NaCl dissociates into Na+ and Cl-).

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