Day 2

Question 1

Synthesis reactions

Answer 1

A reaction where the reactants combine to make a whole. A + B -> AB

Question 2

Decomposition reaction

Answer 2

A reaction where a whole is broken down to parts (which could still be compounds or molecules). AB -> A + B

Question 3

Combustion reaction

Answer 3

Combustion usually occurs when a hydrocarbon reacts with oxygen to produce carbon dioxide and water. In the more general sense, combustion involves a reaction between any combustible material and an oxidizer to form an oxidized product. CxHy(Oz) + O2 -> CO2 + H2O

Question 4

Oxidizer

Answer 4

An oxidizer is a type of chemical which a fuel requires to burn. Most types of burning on Earth use oxygen, which is prevalent in the atmosphere. An oxidizer works by stealing electrons (so it should have a high electron affinity).

Question 5

Electronegativity and how it trends on the PT.

Answer 5

A measure of the tendency of an atom to attract a bonding pair of electrons. As you move down a group on the periodic table, the electronegativity of an element decreases because the increased number of energy levels puts the outer electrons very far away from the pull of the nucleus. Electronegativity increases as you move from left to right across a period on the periodic table since the number of protons are increasing. See https://study.com/academy/lesson/electronegativity-trends-among-groups-and-periods-of-the-periodic-table.html.

Question 6

Top 5 elements in the universe (expected).

Answer 6

1. Hydrogen (1)
2. Helium (2)
3. Oxygen (8)
4. Carbon (6)
5. Neon (10)

Question 7

Nuclide

Answer 7

A species of atom differentiated by its number of protons (Z), neutrons (N), and energy state. Similar to the concept of isotopes but the emphasize is on differences affecting the nuclear rather than chemical properties.

Question 8

Ionization energy

Answer 8

The energy required to remove an electron from a neutral atom.

Question 9

Electron affinity

Answer 9

The energy change when a neutral atom attracts an electron to become a negative ion.

Question 10

Oxidize

Answer 10

The process of taking an electron from an element.

Question 11

Single replacement (displacement) reaction

Answer 11

An element replaces another element in a compound. The analogy is dancing couples. A + BC -> B + AC

Question 12

Double replacement (displacement) reaction

Answer 12

The positive and negative ions of two compound switch places. AB + CD -> AD + CB

Question 13

Limiting reagent

Answer 13

(Or limiting reactant or limiting agent). The first reactant to be used up in a reaction. It limits a given chemical reaction due to its scarcity and is therefore the limiting factor in the continuation of the reaction.

Question 14

Excess reagent

Answer 14

The reactant that exists in excess in a given chemical reaction and is therefore not the limiting factor in the continuation of the reaction.

Question 15

Bohr model

Answer 15

A model of the atom that is analogous to orbiting planets. It is less accurate than the quantum mechanical model but still useful in many contexts.

Question 16

Quantum mechanical model

Answer 16

A model of the atom that describes the movement of electrons around the atom as non-circular “orbitals”.

Question 17

What is an electron shell?

Answer 17

It is a “shell” around the nucleus where electrons probabilistically reside. Electrons in a given shell have a certain energy level.

Question 18

Atomic orbital

Answer 18

The wave function for an electron in an atom (different from orbital).

Question 19

Wave function

Answer 19

A function that, when squared, gives the probability of finding a certain particle within a given region of space.

Question 20

Principle quantum number

Answer 20

n - gives the energy level of an electron (aka, shell). Integers from 1 to infinity. Also sometimes labeled as K, L, M, N, …

Question 21

Angular momentum quantum number

Answer 21

l - gives the shape of the orbital. Is an integer from 0 - n-1. Orbitals of the same n but different l are said to be in different subshells. Integers can be written as s, p, d, f, g

Question 22

Magnetic quantum number

Answer 22

ml - the orientation of the subshell. There are always 2l + 1 orbitals for each subshell, differentiated by m.

Question 23

Spin quantum number

Answer 23

ms - the electron spin (as it orbits). Can be +1/2 or -1/2.

Question 24

Oxide

Answer 24

An oxide is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. “Oxide” itself is the dianion of oxygen, an O2– atom. Metal oxides thus typically contain an anion of oxygen in the oxidation state of −2.

Question 25

Pyrophoric

Answer 25

A substance that ignites spontaneously in air at or below 55 °C (130 °F). Examples are iron sulfide and many reactive metals including plutonium and uranium, when powdered or thinly sliced. The creation of sparks from metals is based on the pyrophoricity of small metal particles, and pyrophoric alloys are made for this purpose.[2] This has certain uses: the sparking mechanisms in lighters and various toys, using ferrocerium; starting fires without matches, using a firesteel; the flintlock mechanism in firearms; and spark-testing ferrous metals.

Question 26

Core electrons

Answer 26

Electrons inside of the valence shell.

Question 27

Mneumic for angular momental quantum number

Answer 27

Scientists, Please! Don’t Forgo Gazing at Heisenberg’s Ill Kicks!.