Question

classify the reactions as endothermic or exothermic.
the reaction between ammonium nitrate and water absorbs heat from the surrounding environment.
three drops of concentrated sulfuric acid added to 100 milliliters of water in a beaker makes the beaker hot.
ammonium chloride dissolved in a beaker of water makes the beaker cold.
uranium atoms are split to produce nuclear energy.
water separates into hydrogen and oxygen when an electric current is run through it.
methane and oxygen are combined to produce methanol and heat.

endothermic reaction \t exothermic reaction

Explanation:

To solve this, we recall:

• Endothermic Reaction: Absorbs heat (surroundings feel cold).
• Exothermic Reaction: Releases heat (surroundings feel hot).

Step 1: Identify Endothermic Reactions

• Reaction 1: “Ammonium nitrate + water absorbs heat” → Absorbs heat (endothermic).
• Reaction 3: “Ammonium chloride dissolved in water makes beaker cold” → Absorbs heat (endothermic).
• Reaction 5: “Water splits into H₂ and O₂ (electrolysis)” → Requires energy (absorbs heat, endothermic).

Step 2: Identify Exothermic Reactions

• Reaction 2: “Concentrated H₂SO₄ + water makes beaker hot” → Releases heat (exothermic).
• Reaction 4: “Uranium split (nuclear fission)” → Releases nuclear energy (exothermic).
• Reaction 6: “Methane + O₂ → methanol + heat” → Releases heat (exothermic).

Final Classification

Endothermic Reaction	Exothermic Reaction
2. Ammonium chloride dissolved in a beaker of water makes the beaker cold.	2. Uranium atoms are split to produce nuclear energy.
3. Water separates into hydrogen and oxygen when an electric current is run through it.	3. Methane and oxygen are combined to produce methanol and heat.

(Note: If you need a concise list without the table, the endothermic reactions are the ones that absorb heat (or make surroundings cold/require energy), and exothermic are those that release heat (or make surroundings hot/produce energy).)

Answer:

To solve this, we recall:

• Endothermic Reaction: Absorbs heat (surroundings feel cold).
• Exothermic Reaction: Releases heat (surroundings feel hot).

Step 1: Identify Endothermic Reactions

• Reaction 1: “Ammonium nitrate + water absorbs heat” → Absorbs heat (endothermic).
• Reaction 3: “Ammonium chloride dissolved in water makes beaker cold” → Absorbs heat (endothermic).
• Reaction 5: “Water splits into H₂ and O₂ (electrolysis)” → Requires energy (absorbs heat, endothermic).

Step 2: Identify Exothermic Reactions

• Reaction 2: “Concentrated H₂SO₄ + water makes beaker hot” → Releases heat (exothermic).
• Reaction 4: “Uranium split (nuclear fission)” → Releases nuclear energy (exothermic).
• Reaction 6: “Methane + O₂ → methanol + heat” → Releases heat (exothermic).

Final Classification

Endothermic Reaction	Exothermic Reaction
2. Ammonium chloride dissolved in a beaker of water makes the beaker cold.	2. Uranium atoms are split to produce nuclear energy.
3. Water separates into hydrogen and oxygen when an electric current is run through it.	3. Methane and oxygen are combined to produce methanol and heat.

(Note: If you need a concise list without the table, the endothermic reactions are the ones that absorb heat (or make surroundings cold/require energy), and exothermic are those that release heat (or make surroundings hot/produce energy).)