Figure 2 H₂O2 (1) - ---> H₂O₂ (g) H₂O₂(aq) -- ---> H₂O (1) + O2 (g) Which of the following statements BEST explain which figure is a model of a chemical change? Figure 2, because there are 3 states of matter present. Figure 1, because H₂O2 changes state of matter. Figure 2, because new substances are produced. Figure 1, because H₂O2 created a product. Figure 1
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
![**Understanding Chemical and Physical Changes: Figures and Analysis**
**Figure 1:**
\[ \text{H}_2\text{O}_2 (\text{l}) \rightarrow \text{H}_2\text{O}_2 (\text{g}) \]
**Figure 2:**
\[ \text{H}_2\text{O}_2(\text{aq}) \rightarrow \text{H}_2\text{O} (\text{l}) + \text{O}_2 (\text{g}) \]
**Question:**
Which of the following statements BEST explains which figure is a model of a chemical change?
1. ( ) Figure 2, because there are 3 states of matter present.
2. ( ) Figure 1, because H₂O₂ changes state of matter.
3. ( ) Figure 2, because new substances are produced.
4. ( ) Figure 1, because H₂O₂ created a product.
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**Explanation:**
- **Figure 1 Explanation:**
- This figure illustrates a physical change where hydrogen peroxide (\[ \text{H}_2\text{O}_2 \]) transitions from liquid (\[ \text{l} \]) to gas (\[ \text{g} \]). The chemical composition of \[ \text{H}_2\text{O}_2 \] remains the same.
- **Figure 2 Explanation:**
- This figure represents a chemical change. Hydrogen peroxide (\[ \text{H}_2\text{O}_2 \]) in aqueous solution (\[ \text{aq} \]) decomposes into water (\[ \text{H}_2\text{O} \]) and oxygen gas (\[ \text{O}_2 \]). New substances are produced in this reaction, indicating a chemical change.
**Best Explanation:**
The third statement, "Figure 2, because new substances are produced," correctly identifies Figure 2 as a model of a chemical change because it involves the creation of new substances (\[ \text{H}_2\text{O} \] and \[ \text{O}_2 \]).](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F57ec2d4b-c990-4be5-9768-0876f517c2e3%2Fa1516fe8-ab64-4e7b-bb23-888e0c9feb97%2F7yexpvg_processed.jpeg&w=3840&q=75)
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