Substance Properties
What are the 4 states of matter?
Solid, Liquid, Gas, and Plasma
Provide 3 examples of different kinds of atoms.
Any three elements.
What are some things that we define as particles in chemistry when using the mole? List two.
molecules, atoms, compounds, formula units, ions
Calculate N
A = 9
Z = 4
N = A - Z
N = 5
Why do helium balloons float?
Helium is less dense than air.
Also explains why it makes your voice high pitched. Soundwaves travel through it faster making the resonant frequency higher in the vocal cords.
Describe the difference between a chemical and physical change and provide one example of each.
chemical = converted into new substance.
physical = change form but NOT composition.
What is the definition of the atom?
Smallest particle of an element that retains the chemical properties of that element.
What is a mole?
6.02 x 10^23 of a thing.
What is the volume in liters of 3 moles of Cl2 gas?
3 moles x 22.4liters/mole = 67.2 liters
According to many specialists, what is becoming the greatest potential threat to humanity?
Artificial Intelligence.
Describe the volume, shape, and kinetic energy of each state of matter.
Solid - definite V/S, lowest KE
Liquid - definite V, indefinite S, medium KE
Gas - indefinite V/S, high KE
Plasma - indefinite V/S, highest KE
Name each part of the atom.
What does the atomic number tell you?
What does the mass number tell you?
How do determine the charge of an element?
Protons, Neutrons, Electrons
Protons
Protons + Neutrons
Number of protons and electrons
Describe why the mole is so important in chemistry. Be specific with your answer.
Allows us to convert between mass, volume, and number of particles.
Nitrogen has 2 stable isotopes. N-14 (14 amu) at 99.36% and N-15 (15 amu) at 0.64%. What is the average atomic mass of nitrogen? (1000th place)
14.008
Why do you think Mars is red?
Surface contains lots of iron oxide...rust.
List and describe each term for converting between each state of matter. (There are 8 in total)
Sublimation = Solid to gas, Deposition = gas to solid, freezing = liquid to solid, Melting = solid to liquid, Vaporization = liquid to gas, Condensation = gas to liquid, Ionization = The losing or gaining of an electron, Recombination = plasma to gas
Name the two significant scientists who establish the atomic theory and their contribution. (The first was a LONG time ago).
Democritus - Theorized existence of tiny particles that everything was made out of.
John Dalton - 5 laws of the atomic theory
Write down the two mole formulas and describe each unknown.
n = m/M
n = # particles/6.02 x 10^23
Determine how many molecules are present in 60 liters of CO2 gas.
1.6125 x 1024 molecules of CO2
Ants are easily the most numerous insects in the world. It is estimated that there are 20 _____ ants worldwide, according to a new census.
a) million b) billion c) trillion d) quadrillion
d) 20 quadrillion ants.
2.5 million for every living human
Describe the difference for each of the following terms and provide an example of each.
Pure vs Mixture?
Molecule vs Compound?
Homogenous vs Heterogenous?
Pure: fixed composition/cannot be separated by physical means.
Molecule: 2 or more atoms bonded (do NOT have to be different)
Homogenous: Evenly mixed throughout
List the three basic laws of how elements combine and describe one of them in your own words.
1. Law of conservation of mass
2. Law of definite proportions
3. Law of multiple proportions
When using the mole road map, you are provided with conversion factors. Determine the conversion factors when going from the mole to
1. mass 2. volume 3. particles
1. grams/mole
2. 22.4L/mole
3. 6.02 x 10^23/mole
Hydrochloric acid has a density of 0.0016 g/cm3. If the average human stomach can hold 5.68 liters of liquid and only 1/8 of the stomach has hydrochloric acid, how many moles of hydrochloric acid is present? (Molecular mass of HCl 36.46)
2x time on this one.
mass = (0.0016 g/cm3) x (0.71liters)
mass = 0.001136grams HCl
moles = (0.001136grams) x (1 mole / 36.46 grams)
moles = 0.000031157 moles or 3.1157 x 10-5
Genetic engineering is at the forefront of science. Briefly describe what is the CRISPER method is used for?
CRISPER method allows us to slice sections of DNA (based on RNA sequence) which can deactivate certain genes or repair disease-causing genes.