Chemistry 12 Final Revision: Chemical Quantities and Nuclear Processes

Practice flashcards covering solution concentrations (molarity, dilution, mass/volume percent) and nuclear processes (radioactive decay, fission, fusion, and stellar nucleosynthesis) according to the provided lecture notes.

What is the definition of a solution?

A mixture made of a solute dissolved in a solvent.

Distinguish between a solute and a solvent.

A solute is the substance being dissolved, while a solvent is the substance that dissolves the solute.

What is the difference between a dilute solution and a concentrated solution?

A dilute solution has a small amount of solute, whereas a concentrated solution has a large amount of solute.

Define molarity ($M$).

The number of moles of solute per liter of solution.

What is the specific formula for calculating molarity?

$$M = \frac{\text{moles of solute}}{\text{liters of solution}}$$

What is a volumetric flask used for?

To prepare precise volumes of solutions.

Define the process of dilution.

The process of lowering concentration by adding more solvent.

What is the dilution formula?

$$M_1V_1 = M_2V_2$$

What quantity remains constant during the dilution of a solution?

The number of moles of solute.

What is a stock solution?

A concentrated solution used to prepare dilute solutions.

How is percent by volume ($\% v/v$) calculated?

$$\text{\% v/v} = \frac{\text{volume of solute}}{\text{volume of solution}} \times 100$$

How is percent by mass ($\% m/m$) calculated?

$$\text{\% m/m} = \frac{\text{mass of solute}}{\text{mass of solution}} \times 100$$

What is radioactivity?

The process by which unstable nuclei emit particles and rays.

Define transmutation.

The conversion of one element into another element.

What is an isotope?

Atoms of the same element with different numbers of neutrons.

According to the Standard Model, what fundamental particle makes up protons and neutrons?

Quark.

What is a lepton?

A small fundamental particle such as an electron.

Which force is responsible for holding protons and neutrons together in the nucleus?

Strong nuclear force.

Which force is responsible for beta decay?

Weak nuclear force.

Describe alpha ($\alpha$) decay.

A decay process where an alpha particle (a helium nucleus) is emitted.

What occurs during beta minus ($\beta^-$) decay?

A neutron changes into a proton and releases an electron.

What occurs during beta plus ($\beta^+$) decay?

A proton changes into a neutron and releases a positron.

What is electron capture?

A process where the nucleus absorbs an inner electron.

Define half-life.

The time required for half of a radioactive sample to decay.

What are the terms for the original unstable isotope and the isotope formed after decay?

The original is the parent isotope, and the resulting one is the daughter isotope.

What is the purpose of radiometric dating?

Determining the age of materials using radioactive isotopes.

Define mass defect.

The difference between the actual atomic mass and the total mass of its individual particles.

What is nuclear binding energy?

The energy required to separate a nucleus into protons and neutrons.

State the equation that relates mass and energy.

$$E = mc^2$$

What is nuclear fission?

The splitting of a large nucleus into smaller nuclei.

What is nuclear fusion?

The combining of small nuclei into a larger nucleus.

Which hydrogen isotopes are used in the fusion example provided in the text?

Deuterium and Tritium ($\text{Deuterium} + \text{Tritium} \rightarrow \text{Helium} + \text{Neutron} + \text{Energy}$).

Distinguish between the proton-proton chain and the CNO cycle.

The proton-proton chain happens in small stars like the Sun; the CNO cycle happens in larger stars where carbon acts as a catalyst to convert hydrogen into helium faster.

What is nucleosynthesis?

The process of forming new elements inside stars.

How are elements heavier than iron formed?

During supernovas or neutron star collisions.

What are the possible end-stages for a large star after a supernova?

Neutron stars or black holes.

According to the Big Bang Theory, when did the universe begin?

About $13.8$ billion years ago.

What is the composition of the universe according to the notes?

Mostly dark energy and dark matter, with a small amount of ordinary matter.

Why is Plutonium-238 useful for Mars rovers?

It has a long half-life and releases energy.

Which instrument is used to detect radioactive particles?

Geiger counter.