I this calculation of the enthalpy of a reaction as measured in a constant pressure telemetry container, I totally get everything except for the exothermic part. I understand that hcl at 25 C mixed with NaOH at 25 degrees gives off h20 and heat, thus exothermic. But what puzzles me is why the formula q = s m delta T yields a positive number indicating an endothermic process. ( final temp higher than initial) **Enthalpy and Calorimetry in Neutralization Reactions**In calorimetry, we observe the enthalpy change during chemical reactions under constant pressure, wherein the entire heat exchange occurs within the solution. Consider the reaction of 50.0 mL of 1.0 M NaOH with 50.0 mL of 1.0 M HCl, both at 25.0°C, resulting in a temperature increase to 31.9°C.**Chemical Reaction:**\[\text{H}^+ (\text{aq}) + \text{OH}^- (\text{aq}) \rightarrow \text{H}_2\text{O} (\text{l})\]**Assumptions:**1. The calorimeter does not absorb or leak heat, simulating pure water with a density of 1.0 g/mL.2. The specific heat capacity of water is 4.18 J/°C · g.**Calculation of Energy Released:**- **Formula:** \[ q = s \times m \times \Delta T \] where $ s $ is the specific heat capacity, $ m $ is the mass of the solution, and $ \Delta T $ is the temperature change.**Example Calculation:**- Mass of solution $ m = 100.0 \, \text{mL} \times 1.0 \, \text{g/mL} = 1.0 \times 10^2 \, g $- Temperature change $ \Delta T = 31.9°C - 25.0°C = 6.9°C $- Energy released $ q = 4.18 \, \text{J/°C} \cdot \text{g} \times 1.0 \times 10^2 \, g \times 6.9°C = 2.9 \times 10^3 \, \text{J} $**Extensive vs. Intensive Properties:**- Extensive properties like heat depend on the amount of substance.- Intensive properties like temperature do not depend on the amount of substance.**Enthalpy of Reaction per Mole of $ \text{H}^+ $:**- Moles of $ \text{H}^+ $ reacted: \[ 50. **Metabolic Activity and Plant Temperature Regulation**In the context of a competitive tropical climate where energy is precious, plants can exhibit significant metabolic activity, sometimes increasing their temperature by as much as 15°C above ambient conditions. This intense heat production can seem counterintuitive given the need for energy conservation. However, certain plants utilize this heat to attract specific pollinating insects. For instance, a plant may create a chemical mixture mimicking the scent of rotting meat, which is appealing to specific insects. The heat "cooks" these chemicals, dispersing them into the air, thereby attracting beetles and flies that feed on flesh. Once inside the plant's pollination chamber, the high temperature (up to 110°F) keeps these insects active for effective pollination.**Enthalpy Change in Acid-Base Reactions**When $ \text{H}^+ $ ions are neutralized, a certain amount of heat is released. The enthalpy change per mole for the reaction:\[ \text{H}^+ (aq) + \text{OH}^- (aq) \rightarrow \text{H}_2\text{O} (l) \]is $-58 \text{ kJ/mol}$, indicating that heat is evolved. In general, when an object undergoes a change in temperature, the heat can be calculated using the equation:\[ q = s \times m \times \Delta T \]where $ s $ is the specific heat capacity, $ m $ is the mass, and $ \Delta T $ is the change in temperature. If $ \Delta T $ is positive, it signifies that the object has absorbed heat, resulting in an increased temperature.**Constant-Pressure Calorimetry Experiment**In a calorimetry experiment, 1.00 L of 1.00 M $\text{Ba(NO}_3\text{)}_2$ solution at 25.0°C is mixed with 1.00 L of 1.00 M $\text{Na}_2\text{SO}_4$ solution at the same temperature. This results in the formation of $\text{BaSO}_4$ as a white solid, and the temperature of the mixture rises to 28.1°C. Assuming the calorimeter absorbs minimal heat, the specific heat capacity of the solution is 4.18 J/g°C, and its density

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Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

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I this calculation of the enthalpy of a reaction as measured in a constant pressure telemetry container, I totally get everything except for the exothermic part. I understand that hcl at 25 C mixed with NaOH at 25 degrees gives off h20 and heat, thus exothermic. But what puzzles me is why the formula q = s m delta T yields a positive number indicating an endothermic process. ( final temp higher than initial)

**Enthalpy and Calorimetry in Neutralization Reactions**

In calorimetry, we observe the enthalpy change during chemical reactions under constant pressure, wherein the entire heat exchange occurs within the solution. Consider the reaction of 50.0 mL of 1.0 M NaOH with 50.0 mL of 1.0 M HCl, both at 25.0°C, resulting in a temperature increase to 31.9°C.

**Chemical Reaction:**
\[
\text{H}^+ (\text{aq}) + \text{OH}^- (\text{aq}) \rightarrow \text{H}_2\text{O} (\text{l})
\]

**Assumptions:**
1. The calorimeter does not absorb or leak heat, simulating pure water with a density of 1.0 g/mL.
2. The specific heat capacity of water is 4.18 J/°C · g.

**Calculation of Energy Released:**
- **Formula:**
\[
q = s \times m \times \Delta T
\]
where $ s $ is the specific heat capacity, $ m $ is the mass of the solution, and $ \Delta T $ is the temperature change.

**Example Calculation:**
- Mass of solution $ m = 100.0 \, \text{mL} \times 1.0 \, \text{g/mL} = 1.0 \times 10^2 \, g $
- Temperature change $ \Delta T = 31.9°C - 25.0°C = 6.9°C $
- Energy released $ q = 4.18 \, \text{J/°C} \cdot \text{g} \times 1.0 \times 10^2 \, g \times 6.9°C = 2.9 \times 10^3 \, \text{J} $

**Extensive vs. Intensive Properties:**
- Extensive properties like heat depend on the amount of substance.
- Intensive properties like temperature do not depend on the amount of substance.

**Enthalpy of Reaction per Mole of $ \text{H}^+ $:**
- Moles of $ \text{H}^+ $ reacted:
\[
50.

**Metabolic Activity and Plant Temperature Regulation**

In the context of a competitive tropical climate where energy is precious, plants can exhibit significant metabolic activity, sometimes increasing their temperature by as much as 15°C above ambient conditions. This intense heat production can seem counterintuitive given the need for energy conservation. However, certain plants utilize this heat to attract specific pollinating insects. For instance, a plant may create a chemical mixture mimicking the scent of rotting meat, which is appealing to specific insects. The heat "cooks" these chemicals, dispersing them into the air, thereby attracting beetles and flies that feed on flesh. Once inside the plant's pollination chamber, the high temperature (up to 110°F) keeps these insects active for effective pollination.

**Enthalpy Change in Acid-Base Reactions**

When $ \text{H}^+ $ ions are neutralized, a certain amount of heat is released. The enthalpy change per mole for the reaction:
\[ \text{H}^+ (aq) + \text{OH}^- (aq) \rightarrow \text{H}_2\text{O} (l) \]
is $-58 \text{ kJ/mol}$, indicating that heat is evolved. In general, when an object undergoes a change in temperature, the heat can be calculated using the equation:
\[ q = s \times m \times \Delta T \]
where $ s $ is the specific heat capacity, $ m $ is the mass, and $ \Delta T $ is the change in temperature. If $ \Delta T $ is positive, it signifies that the object has absorbed heat, resulting in an increased temperature.

**Constant-Pressure Calorimetry Experiment**

In a calorimetry experiment, 1.00 L of 1.00 M $\text{Ba(NO}_3\text{)}_2$ solution at 25.0°C is mixed with 1.00 L of 1.00 M $\text{Na}_2\text{SO}_4$ solution at the same temperature. This results in the formation of $\text{BaSO}_4$ as a white solid, and the temperature of the mixture rises to 28.1°C. Assuming the calorimeter absorbs minimal heat, the specific heat capacity of the solution is 4.18 J/g°C, and its density

Expert Solution

Step 1

Step 1) If q in this equation telling us about the difference of energy in the initial system and final system is exothermic or endothermic.

When q is negative, the energy is released from the system to the surroundings and if q is positive, the energy is being taken from surrounding to the system.

Let us take an example for better understanding:

let us take pot of water in when water is boiled, the energy has to go in some system in the form of heat. Due to which the average temperature of water is greater than earlier ( positive $∆ T$ ). But when pot of boiled water cools, energy will leave the system, so water will be cooled down than earlier ( negative $∆ T$ ).

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