LTHS Chemistry Midterm

steps of the scientific method

1. observation

2. hypothesis

3. perform experiment

4. repeat

hypothesis vs. theories

hypothesis: not proven

theory: almost fact, has been tested with many experiments

theory vs. law

theory: can change

law: it’s true

physical property: definition and;examples?
something that can be observed w/o performing a chemical change: color, 5 cm long
chemical change vs. physical change

chemical change=must change actual atoms composition

physical change=can be reversed

heterogeneous mixture?

you can see difference between particles in mixture

.;;;;;; What is the common name for a homogeneous mixture?

solution

;Describe how the process of distillation works.

has to do with boiling water and evaporating water and stuff is left behind
difference between element, compound,;and mixture

element=1 element

compound=2+ elements (usually will be a written out compound)

mixture=2+ elements (usually a common object)

law of conservation of mass and energy
mass and energy are neither destroyed or created
observation vs. inference

observation: you see it happen

inference: an opinion/don’t actually observe it

qualitative and quantitative observations

qualitative: w/o numbers

quantitative: with numbers

accuracy vs. precision

accuracy:close to actual answer (if actual answer is 3, accuracy is 3,3.5,4,2)

precision:answers close together to each other (if answer=3, precision is 8,9,10,11)

know how to write in scientific notation

try: 30000 and .0005

30000=3.0 x 10^4

.0005= 5.0 x 10^4

KNOW RULES FOR SIG FIGS

 Name the metric unit for:

a. mass          b. volume              c. length                 d. heat

A.grams 

B.liters

C.meter

D.celcius

difference between mass and weight

mass: how much matter is in an object

weight: mass and gravity together

density of water
1 gram per mL
how can you predict if something will sink or float?

if it has a density less than water, it will float

but, more, and it will sink.

put these in order from largest to smallest

meter, hectameter, centimeter, decimeter, millimeter, kilometer, dekameter

kilometer, hectameter, dekameter, meter, decimeter, centimeter, millimeter

 

(Karen hailed down 1 darn cab, man!!)

An element with an equal number of protons and electrons is called a(n)______.

atom

metalloid

the elements surrounding the squiggly line on the periodic table of elements.

binary vs. ternary

binary=2 elements

ternary=3+ elements

acid, molecular, ionic

acid-starts with hydrogen

molecular-2 nonmetals

ionic-metal and nonmetal

conversion of moles to L
22.4 L to moles
empirical or molecular
i don’t know the difference…
double replacement, single replacement, decomposition, combustion, synthesis

synthesis=coming together

double replacement=cations switch

single replacement=cation switches with other

decomp=breaks down

combustion=products are H20 and CO2

  1. What are the products when ANY hydrocarbon is burned?

;

H20 and CO2

What dangerous products are formed through incomplete combustion?

CO

STUDY HOW YOU KNOW IF RXN’s WORK!!!

study pink sheet

  • one of reactants must be an aqueous solution

 

catalyst
speeds up a Rxn
exothermic reaction vs. endothermic reaction

exo-energy given off, number is a product, delta H is negative

endo-energy absorbed, number is a reactant, delta H is positive

LOOK OVER NOMENCLATURE.

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