Double-displacement Reaction

Observations | Reaction Type | Complete and Balance | 1. When heated in oxygen, magnesium gives off a bright white flame. | combination reaction | 2Mg + O2-----> 2MgO | 2. Bubbling and fizzing occurs; the zinc appears to “dissolve” and what appears to be “steam” comes off out of container. | single-displacement reaction | Zn + 2 HCl (aq) --> ZnCl2(aq) + H2(g) | 3. Black smoke occurs | decomposition reactions | 2 (H2O2)(aq) MnO2 2 (H2O) + (O2) | 4. reddish-brown deposit on the surface of iron; surface of the iron is found corroded; the blue solution turns light green | single-displacement reaction | Fe + CuSO4(aq) --> FeSO4 + Cu | 5. PbSO4 (milk white) | double-displacement reaction | Pb(NO3 )2(aq) + H2SO4(aq) --> PbSO4 + 2HNO3 | 6. CaCO3 (s) appears to dissolve and lot of bubbles comes off out of container. | double-displacement reaction | CaCO3 (s) + 2 HCl(aq) --> CaCl2(aq) + CO2(g) + H2O(l) | 7. When copper sulfate hydrate was heated, we can see some white precipitate. | decomposition reactions | CuSO4·5H2O(s) → CuSO4(s) + 5H2O(g) | 8. Red litmus paper changes to blue color; white precipitate. | double-displacement reaction | 2 Na2O2(s) + 2 H2O(l) = 4 NaOH(aq) + O2(g)↑ | 9. purple KMnO4 changes to yellow brown | double-displacement reaction | FeSo4(aq) + KMnO4 (aq) = KMnSo4 + FeO4 ( 8 H2SO4 + 2 KMnO4 + 10 FeSO4 = 5 Fe2(SO4 )3 + 2 MnSO4 + K2SO4 + 8H2O) | 10. Blue litmus changes to red; base becomes acid. | acid-base reactions | Na2CO3 +2HCl -> 2NaCl + H2O + CO2 |
TYPES OF CHEMICAL REACTIONS

POST-LAB QUESTIONS 1. Manganese dioxide (MnO2) was added to the test tube containing hydrogen peroxide (H2O2).
Why was this added? The MnO2 acts like a Catalyst in H2O2 speeding up the breakdown.

What can be the manganese dioxide be called when it is used for this purpose?
Catalyst
2. What color did the litmus paper turn to when you tested tap water? Red
Make a