A reaction has a rate constant of 0.36×10-2s-1 at 22°C, and a rate constant of 0.36 x 10+2 s-1 at 210°C. What is the activation energy? 13) A) 114kJ/mol B) 32.5kJ/mol C) 56.6 kJ/mol D) 1.83 kJ/mol E) 18.1 kJ/mol
Long-term memory occurs
when exceptionally strong action potentials occur
when neurons are permanently changed
in the limbic system
in the cerebellum
The correct answer and explanation is :
Activation Energy Calculation
To determine the activation energy ((E_a)) of the reaction, we use the Arrhenius equation in its logarithmic form:
[
\ln \left( \frac{k_2}{k_1} \right) = \frac{E_a}{R} \left( \frac{1}{T_1} – \frac{1}{T_2} \right)
]
where:
- ( k_1 = 0.36 \times 10^{-2} \, s^{-1} ) at ( T_1 = 22^\circ C = 295K )
- ( k_2 = 0.36 \times 10^{2} \, s^{-1} ) at ( T_2 = 210^\circ C = 483K )
- ( R = 8.314 \, J/(mol \cdot K) )
Substituting the values:
[
\ln \left( \frac{0.36 \times 10^2}{0.36 \times 10^{-2}} \right) = \frac{E_a}{8.314} \left( \frac{1}{295} – \frac{1}{483} \right)
]
[
\ln (10^4) = \frac{E_a}{8.314} \left( \frac{1}{295} – \frac{1}{483} \right)
]
[
9.21 = \frac{E_a}{8.314} \times (0.00339 – 0.00207)
]
[
9.21 = \frac{E_a}{8.314} \times 0.00132
]
Solving for ( E_a ):
[
E_a = \frac{9.21 \times 8.314}{0.00132} = 114,000 \, J/mol = 114 \, kJ/mol
]
So, the correct answer is:
A) 114 kJ/mol
Long-Term Memory Formation
Correct answer: “when neurons are permanently changed.”
Long-term memory (LTM) occurs when neurons undergo lasting structural and functional changes that enable the retention of information over long periods. This process involves synaptic plasticity, where synapses strengthen or weaken in response to activity.
Mechanisms of Long-Term Memory Formation:
- Synaptic Changes – Long-term potentiation (LTP) strengthens synaptic connections between neurons, making future transmission easier.
- Protein Synthesis – New proteins are required to stabilize synaptic changes, supporting lasting memories.
- Neurogenesis & Dendritic Growth – Structural changes occur in neurons, including the growth of new dendritic spines.
- Hippocampus & Cortex – Memory formation involves the hippocampus initially, but over time, memories are stored in the cerebral cortex.
This process differs from short-term memory, which relies on temporary electrical activity rather than lasting neural changes.
