34 Questions
What is Hess's Law related to?
The enthalpy change of a reaction
What is unique to every compound?
Its own heat of formation
What does the heat of formation of a compound represent?
The energy required to form a compound
What is the significance of Hess's Law?
It helps in calculating the enthalpy change of a reaction
What is the unit of heat of formation?
kJ/mol
What is the relationship between the enthalpy change of a reaction and the number of steps involved?
The enthalpy change is independent of the number of steps
What is the probable decay process of 234 into 230?
Alpha emission
What is the resulting element when Uranium (92) decays into?
Thorium
What type of reaction occurs in an electrolytic cell?
Redox reaction
What is true about light elements with even numbers of protons and neutrons?
They are always stable
What is the atomic number of Uranium?
92
What is the charge of the Zn ion in the reaction?
2+
What is the atomic number of Thorium?
90
What happens to the Zn atom during the reaction?
It gets smaller
What is the type of radiation emitted when a nucleus emits a positron?
Beta radiation
What is the role of atom C in the reaction?
It pulls electrons to itself
What is the symbol of the element with atomic number 4?
He
What is the result of the reaction on the Cu atom?
It gets bigger
What is the direction of electron flow in the reaction?
From C to D
What is the lecture topic of the given content?
Chemistry for Engineering
What is the purpose of a bomb calorimeter?
To measure the heat emitted by a sample under controlled conditions
What happens to energy during energy transfer or transformation?
Some energy is lost as heat
What is the result of energy loss as heat?
An increase in entropy
What is the context in which the heat emitted by a sample is measured?
Under controlled conditions
What is the study of the relationships between heat, work, and energy?
Thermodynamics
What is the lecture series about?
Chemistry for Engineering
What is the half-life of Iodine-131?
8 days
How many grams of Iodine-131 will remain after 16 days if you start with 200 grams?
100 grams
What type of decay is K-42 related to?
Beta decay
What is the result of 2 half-lives of Iodine-131 decay?
25 grams remaining
What is the purpose of a decay equation?
To make a radioactive isotope stable
How many half-lives are required for 200 grams of Iodine-131 to decay to 25 grams?
3 half-lives
What is the result of 4 half-lives of Iodine-131 decay?
3.125 grams remaining
How long will it take for 200 grams of Iodine-131 to decay to 12.5 grams?
32 days
Study Notes
Heat Formation and Bomb Calorimeter
- Every compound has its own heat of formation
- A bomb calorimeter is used to measure the heat emitted by a sample burned under controlled conditions
Hess's Law
- States that the enthalpy change of a reaction is the same, regardless of whether it occurs in one step or a series of steps
- Energy transfer or transformation leads to an overall increase in entropy, with some energy lost as heat
Redox Reaction and Electrolytic Cells
- Example of a redox reaction: Zn (2+) will be an ion, while Cu will be neutral
- Zn gradually deteriorates, while Cu grows larger during the reaction
Radioactive Decay
- 234U decays via alpha emission, then positron decay
- If the number of protons and neutrons in light elements are even, they are stable
- Heavy elements (83 and above) are unstable and undergo radioactive decay
- Intermediate elements (21-82) are also unstable
Half-Life of Iodine-131
- Iodine-131 has a half-life of 8 days
- If there are 200 grams of Iodine-131, after 32 days, 25 grams will remain
Solve problems related to stoichiometry, Hess's law, and chemical reactions. Practice calculating molar masses and quantities in chemical reactions.
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