Question

1. classify the reactions in the \test your knowledge\ section of the animation:

a. zn + cuso₄ → cu + znso₄
b. hbr + naoh → nabr + h₂o
c. c₃h₈ + 5o₂ → 3co₂ + 4h₂o
d. pbbr₂ → pb + br₂

1. are there any similarities between any of the reaction categories that would make it hard to tell whether a reaction belonged to one category or another? explain how you would differentiate between them.
2. these ones dont look exactly like the ones in the animation, but what category do you think makes the most sense for them? justify your classification.

a. c₂h₅oh + 3o₂ → 2co₂ + 3h₂o
combustion
b. p₄ + 5o₂ + 6h₂o → 4h₃po₄
c. 2nahco₃ → co₂ + na₂co₃ + h₂o
d. co₂ + h₂o → h₂co₃
association of chemistry teachers
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Explanation:

• a. \(C_{2}H_{5}OH + 3O_{2}\to2CO_{2}+3H_{2}O\)：Combustion reactions involve a substance reacting with oxygen (\(O_{2}\)) to produce oxides and usually release heat. Here, ethanol (\(C_{2}H_{5}OH\)) reacts with \(O_{2}\) to form carbon dioxide (\(CO_{2}\)) and water (\(H_{2}O\)), which is characteristic of a combustion reaction.
• b. \(P_{4}+5O_{2}+6H_{2}O\to4H_{3}PO_{4}\)：This is a combination reaction. In a combination reaction, two or more substances react to form a single product. Here, phosphorus (\(P_{4}\)), oxygen (\(O_{2}\)), and water (\(H_{2}O\)) combine to form phosphoric acid (\(H_{3}PO_{4}\)).
• c. \(2NaHCO_{3}\to CO_{2}+Na_{2}CO_{3}+H_{2}O\)：This is a decomposition reaction. Decomposition reactions involve a single reactant breaking down into two or more products. Sodium bicarbonate (\(NaHCO_{3}\)) decomposes into carbon dioxide (\(CO_{2}\)), sodium carbonate (\(Na_{2}CO_{3}\)), and water (\(H_{2}O\)).
• d. \(CO_{2}+H_{2}O\to H_{2}CO_{3}\)：This is a combination reaction. Carbon dioxide (\(CO_{2}\)) and water (\(H_{2}O\)) combine to form carbonic acid (\(H_{2}CO_{3}\)).

Answer:

a. Combustion reaction
b. Combination reaction
c. Decomposition reaction
d. Combination reaction