Math in Chemistry
How many significant figures does this number have?
1.00020
6
_____ is the variable that is changed in an experiment, _____ is the variable that is measured in an experiment.
What is Independent variable, dependent variable?
This is the simplest form of matter.
What is the atom?
What do we call rows and columns of the periodic table?
Rows are periods, columns are groups.
What is the difference between accuracy and precision?
Accuracy is based on how close a result is to the actual correct number, precision is based on how close multiple results are to each other.
Water, H2O, is this type of matter.
What is a compound?
This is the subatomic particle responsible for the identity of the atom.
What is the proton?
Being brittle and poor conductors of electricity are characteristics of this type of elements.
What are non-metals?
____ lose electrons, so they are ____ charged.
Cations, positive
Convert this number to scientific notation:
1,350,000,000
Convert this number to standard notation:
4.2 x 104
1.35 x 109
42,000
What is the difference between a compound and a mixture?
Compounds are substances which can be formed by chemically combining two or more elements. Mixtures are substances that are formed by physically mixing two or more substances
Mass number is # of protons + # of neutrons of one atom, which will always be a whole number. Average atomic mass is the average mass of all atoms of that element, so it is not a whole number.
Mass numbers of all atoms of that element are averaged to find our average atomic mass.
Carbon-12
This term describes the effect that shells of electrons have at blocking the nucleus from valence electrons, decreasing the nucleus' pull on the valence electrons.
What is shielding effect?
How many nm are in 0.65 m?
(1 m = 1,000,000,000 nm)
6.5 x 108 = 650,000,000
What is the difference between a chemical change and a physical change?
A physical change alters the substance without altering its chemical composition, is usually reversible, and does not create new products (ex: melting). A chemical change alters the chemical composition of a substance, is not reversible, and creates new products (ex: burning wood).
What are the different parts of the atom and how do they stay together?
The atom is a made up of a 1) nucleus that contains protons (+ charge) and neutrons (0 charge) and 2) an electron cloud which holds our electrons (- charge). These two parts are held together by the attractive electromagnetic force between the electrons and protons. The nucleus is held together by the strong nuclear force overcoming the repulsion force of the protons form themselves.
What type of bond will form between a metal and a non-metal and why?
An ionic bond will form between a metal and a nonmetal because of their large difference in electronegativity: a non-metal really wants to gain electrons (high electronegativity) and a metal really wants to lose electrons (low electronegativity). Therefore, the metal will readily give its electron(s) to the non-metal, making this an ionic bond.
How does an electron jump from ground state to excited state?
Energy must be added to the system for an electron to jump from ground state to excited state
Calculate the wavelength of a wave if the frequency is 3.5 x 1014 Hz.
c = λν
c = 3.0 x 108 m/s
Wavelength = 8.6 x 10-7 m
Density is an example of this type of property, not dependent on the amount of the substance present.
What is the intensive property?
*Bonus points for sharing an example of an extensive property (+100 extra)
Come up to the board and draw 1) a Bohr model and 2) a Lewis Structure of magnesium
Let's see it
Come up to the board, draw an outline of a periodic table, and then draw arrows showing trends for 1) atomic radii 2) ionization energy 3) electronegativity 4) reactivity for metals 5) reactivity for nonmetals
Increase right to left and up to down: atomic radii, reactivity for metals
Increase left to right and down to up: ionization energy, electronegativity, reactivity for nonmetals
Come up to the board and write 1) complete electron configuration and 2) noble gas configuration of iron (Fe)
Complete electron configuration: 1s22s22p23s23p64s23d6
Noble gas configuration: [Ar]4s23d6