chem 30 oct exam

ionic

metals and nonmetals

molecular

non metals and non metals

polyatomic

metal and polyatomic ion

greek prefixes

dont crisscross
mono
di
tri
tetra
penta
hexa
hepta
octa
nona
deca

what acids are hydro ic

binary, start with H

acids rules

mite be a hippopotamous, ate something icky

on a mp/bp graph, what happens if the substance is doubled

the line is stretched out, so it takes longer, but it has the same mp/bp plateaus

on a mp/bp graph, what happens if heat added/min is doubled

the line gets steeper, so it moves faster, but the mp/bp plateaus stay the same

are acids still binary if they have a polyatomic ion

no

whmis gas cylinder

compressed gas

whmis flame with line under it

flammable material

whmis flame with circle

oxidizing

whmis explosion

explosion hazard

whmis skull and crossbones

harmful or fatal

whmis 3 half circles

biohazardous/infectious

whmis liquid being poured out of cylinders

corrosive

whmis body with star on middle

health hazard

whmis exclamation point

harmful

whmis tree

harmful to the environment

whmis

Workplace Hazardous Materials Information System

SDS

safety data sheets. The SDS includes information such as the properties of each chemical; the physical, health, and environmental health hazards; protective measures; and safety precautions for handling, storing, and transporting the chemical.

measurements

made by scientists to determine size, length, and other properties of matter. for measurements to be useful, a measurement standard must be used. a standard is an exact quantity that people agree to use for comparison

SI (metric system)

is the standard syste, of measurement used worldwide by scientists (base 10)

error in measurements

two kinds of numbers are used in science
-counted or defined: exact numbers, no uncertainty. ex. 1km=100m
-measured: are subject to error, have uncertainty

uncertainty

every measurement has uncertainty becuase of instrument limitations and human error. the last digit is the estimated one. ex. on a ruler that shows cm, 8cm would be the certain digit, but if you said 8.6, 6 would be the uncertain digit

miniscus

the dip in the liquid level when measuring a liquid, you read from the bottom of the miniscus

what are significant numbers

the certain and uncertain digits

sig fig rules

leading zeros- not significant
sandwiched zeros- signigicant
all non zero digits- significant
trailing zeros after decimal- significant

sig figs and calculations

the results of a calculation cant be more precise than the least precise measurement.
for multiplication and divsion, the answer must contain the same # of sig figs as there are in the measurement with the fewest sig figs.
for addition and subtraction, the answer must have the same number of dec places as there are in the measurement with the fewest dec places

measurements are said to be precise if

they yield very similar results when repeated in the same manner

measurement- accurate and precise

a measurement is considered accurate if it yields a result that is very close to the true or accepted value. precise values agree with each other, accurate values agree with a true value

can a conversion factor be given as a percentage

yes

classification of matter

matter is anything that has mass, and occupies space. mass=amount of matter.
matter can be classified by its physical state as solid, liquid, or gas

what are the condensed states

solid and liquid

solid 5

-Densely packed matter with definite shape and volume.
- Particles hare strong forces of attraction (intermolecular forces-IMFs) towards each other
- Solids are not very compressible
There are crystalline and amorphous solids. Crystalline solids have a regular pattern of particles that repeats, Such as ionic compounds.
Amorphous particles have a random placement of particles. plastic and glass are examples of amorphous compounds.
- solid particles vibrate in fixed positions

plasma

ionized gas- all particles are charged

liquid 4

Loosely packed matter with definite volume but indefinite shape.
- Particles have moderate forces of attraction towards each other and are mobile - take the shape of their container
- particles have translational motion
- Liquids are slightly compressible.

gas 6

-very loosely packed matter with no definite shape or volume
- Particles have little or no forces of attraction towards each other.
- Gases are very compressible.
-Gases can move by diffusion which is movement of particles from an area of high concentration to an area of low concentration
-They can also move by effusion which is movement of gas particles from an area of high pressure to an effusion area of low pressure
- gases, like liquids, are fluids. Fluids can flow.

fluids

substances that can be poured

pressure and its measurement

Pressure is the result of collision of gas particles with the sides of the container. Pressure is defined as the force per unit area
Pressure is measured in units of atmosphere (atm) or mmHg or torr.
The SI unit of pressure is pascal (Pa) or kilopascal (kPa).

atmospheric pressure

can be measured with the use of a barometer. Mercury is used in a barometer due to its high density. At sea level, the mercury stands at 760 mm above its base.

barometer

has a vacuum= the pressure of the atmosphere above the hg dish pushes the hg inside the tube.
low pressure= hg falls
high pressure= hg rises

pressure of a gas prop

is directly proportional to the number of particles (moles) present.

pure substance

fixed composition and properties (a physical process)

mixture

variable composition and properties (a physical process)

element

pure substance that is made up of only one type of atom (a chemical reaction)

compound

properties are unique compared to its components. smallest particle is a molecule. several elements chemically combined (a chemical reaction)

homogenous mixture

uniform

heterogeneous mixture

nonuniform

physical and chemical properties 3

- The characteristics of a substance are called its properties.
- Physical properties are those that describe the matter without changing (same substance) its composition. Examples are density, color, melting and boiling points, and electrical conductivity.
- Chemical properties are those that describe how matter behaves in combination with other matter and involve change in its composition. (turns into a new substance)
Examples are flammability, corrosion, and reactivity with acids.

physical and chemical changes 5

- Changes in physical properties of matter that do not involve change in its composition are called physical changes.
- Examples are melting, evaporation and other phase changes. Physical changes are easily reversible. dissolving is a physical change (mixing)

- A change that alters the chemical composition of matter, and forms new substance is called a chemical change
- Examples are burning, rusting, and reaction with acids.
- Chemical changes are not easily reversible, and are commonly called chemical reactions.
evidence of a chemical change = colour change, gas formed, light released, heat released

temperature and heat 3

- Heat is the thermal energy that is transferred from one body to another because of temperature difference between the bodies.
- Heat flows occurs from high temp to low temp.
- Temp is the average kinetic energy of molecules in a substance. K.E= energy of motion. Fast = high KE

heat transfer 6

- When there is a temperature difference between two objects, heat flows from the warmer to the cooler obiect.
- Transfer of heat occurs by one of three methods: conduction, convection, and radiation.
- Conduction is transfer of heat by contact between two objects through molecular vibration of particles spreading through the sulostance
- Metals are good conductors of heat, while glass and wood are poor conductors (insulators).
- Convection is transfer of heat by actual motion of molecuves.
Liquids and gases transfer heat mainly by convection. (warm air rises)
- Radiation is transfer of heat without molecules. Heat from the sun reaches the earth through space by radiation.

kinetic molecular theory of gas 6

The behavior of gases is described by five key points:

Gases are made of small particles (atoms or molecules) that move randomly at high speeds.
Gas particles have negligible attraction to each other, so attractive forces can be ignored.
The distance between gas particles is large compared to their size, making the volume they occupy small relative to the total gas volume.
Gas particles move in straight lines and collide elastically with each other and the container, causing pressure.
The average kinetic energy of gas particles is directly proportional to the absolute temperature (Kelvin)

kinetic energy distribution curve

This average KE plot shows the number of particles having a certain speed in a sample of a substance at a certain temperature. Average kinetic energy is directly proportional to temperature. At temperature 2 most of the particles are warmed up and are moving faster with a higher kinetic energy.

change of state

- When matter releases or absorbs energy without a change in temperature, phase change occurs (e.g. melting, evaporation).

solid to gas

sublimation (no liquid occurs)

gas to solid

deposition (no liquid occurs)

solid to liquid

melting

liquid to solid

freezing

liquid to gas

vaporization

gas to liquid

condensation

if the order is solid-liquid-gas, what happens to energy when the change of state is moving to the right

energy is absorbed when moving to the right

if the order is solid-liquid-gas, what happens to energy when the change of state is moving to the left

energy is released when the change of state is to the left

phase changes that involve absorption of heat

cooling processes

heat and cooling curves

- When heat is added to ice, it absorbs the heat without a change in temperature, causing a phase change.
- Similarly, when heat is added to hot water, a phase change occurs without an increase in temperature.

mp and bp graph

vapor pressure

the pressure of a vapor above its liquid or solid