Chemistry Study guide: Structure 1.1 and 1.2

what is the set up of distillation?

(know the parts and their functions)

what is the plum pudding model?

* thompson
* disproved by bohr and rutherford because of the gold foil method and bohrs model

what is bohrs model?

disproved the plum pudding model

how many sigfigs are in 1) 10.04 2) 0.0065 3) 6000

1) 4 2) 2 3) 1

what are the changes of matter? (on a heating curve)

heating (left → right) cooling (right → left)

what are the conversions for Celsius and Kelvins?

100C → 373K, 0C → 273K, -273C → 0K

How do you double the kinetic energy of a state of matter?

covert the Celsius temperature to Kelvins, double it, then convert it back to Celsius

what are atoms?

the smallest unit of a particle (ex. H, Cl, H-Cl is two atoms, H-H is two hydrogen atoms)

what are elements?

a pure substance that cannot be broken down into a simpler substance by chemical means (all known elements are on the periodic table) (ex. O**2, H*2, S*8, C*60)*

what are compounds?

a pure substance formed from two or more different elements chemically joined in a fixed ratio (ex. HCl, H\**2O, Al*2O*2, NaCl*). compounds have different properties from the elements they are made from (ex. NaCl has different properties than the elements it is made from)

what are molecules?

two or more atoms (covalent → two non-metal elements)

what are pure substances?

a single kind of matter that cannot be separated into other kinds of matter by physical means (ex. element, compound)

what is a mixture (mixed substance)?

contains more than one element and/or compound that are not chemically bonded together and so retain their individual properties (ex. water and oil)

what is a homogeneous mixture?

has the same uniform appearance and composition throughout (ex. a salt solution)

what is a heterogeneous mixture?

consists of visibly different substances pr phases (ex. sand and water)

what are the techniques of separation?

* filtration:
* separation technique used to separate a heterogeneous mixture like sand and water
* evaporation:
* separation technique used to separate a homogeneous mixture like a salt solution
* distillation:
* separation technique used to separate two miscible (capable of being mixed) liquids with different boiling points
* chromatography:
* separation technique used to separate a mixture of solutes in a solvent

what are the properties of solids, liquids, and gases?

* solid:
* fixed shape
* fixed volume
* limited compressibility
* has no fluidity
* liquid:
* no fixed shape
* fixed volume
* limited compressibility
* flows easily
* gas:
* no fixed shape
* no fixed volume
* high compressibility
* diffuses easily

what does endothermic mean?

energy is absorbed (hot) (solid → liquid (melting), liquid → gas (evaporation), solid → gas (sublimation))

what does exothermic mean?

energy is released (cold) (gas → liquid (condensation), liquid → solid (freezing), gas → solid (deposition))

what are the state symbols for chemical reactions?

s = solid, l = liquid, g = gas, aq = aqueous (in solution)

what are nucleons?

protons and neutrons (they are in the nucleus)

what are the relative masses and relative charges of protons, neutrons, and electrons?

* protons:
* relative mass: 1
* relative charge: +1
* neutrons:
* relative mass: 1
* relative charge: 0
* electrons:
* relative mass: 5 x 10\*-4
* relative charge: -1

how do you draw an atom symbol?

(if it has a charge it is an ion and the charge goes in the top right corner)

what is a cation and an anion?

* cation:
* positive ion (more protons than electrons)
* anion:
* negative ion (more electrons than protons)

what is the only element that has more protons than neutrons in an atom?

hydrogen; 1 proton and no neutrons

what are isotopes?

* isotopes are elements with different amounts of neutrons and therefore different mass numbers (same protons)
* differ in physical properties that depend on mass (density, rate of diffusion, etc)
* the different physical properties include melting point, boiling point, density, etc
* same chemical properties (react the same way)

Isotopes have the same a) __ properties, but different b) __ properties

a) chemical b) physical

what is important about the mass spectrum?

* gives the number of isotopes
* gives the abundance of each isotope

what is relative atomic mass?

* average mass of an atom according to the relative abundances of its isotopes

how do you find relative atomic mass?

multiply the percentage of the isotope with the mass number and add that to the next isotope. ex. Cl-35 (75%) and Cl-37 (25). (75/100 x 35)+ (25/100 x 37) = relative atomic mass amu (atomic mass unit)

example question of RAM (relative atomic mass)

iridium has a RAM of 192.22 and has isotopes Ir-191 and Ir-193. Calculate the percentage composition.

Work:

191 \~ (1 - x) because it is 100- the percentage of 193

193 \~ x because it is the percentage being looked for

191 (1 - x) + 193x = 192.22

Answer:

x = 0.61, so

Ir-193 = 61%

Ir-191 = 39%

what is a separating funnel?

* technique used for immiscible liquids (liquids that don’t mix together)
* separating funnel used in the progress
* method:
* once liquids are in the funnel you wait until they form two layers
* denser liquid sinks to bottom and other liquid goes to top
* conical flask is placed at bottom to collect the denser liquid
* valve allows you to control when and how the liquid is let through down to the conical flask

what is gravity filtration?

* filtration also separates an insoluble solid from a liquid, but it is a more reliable way
* method:
* place filtration paper (making sure it is folded correctly) into the filter
* either use a stand to support the filter over a beaker
* pour the mixture into the funnel and the liquid should be collected in the beaker/conical flask while the solid, now called the residue, stays on the filter paper
* the liquid is now called the filtrate
* to gain back the solid from the residue, evaporate the water from the filter paper

what was the Gold Foil Experiement?

* Rutherford
* demonstrated the atom is largely empty space occupied by the negatively charged electrons surrounding a very dense positively charged nucleus.

WHAT IS THE FORMAT OF THE TEST?

15 MULTIPLE CHOICE

10 SHORT/LONG ANSWER