Science 30 chemistry unit

what are empirical properties

can be observed, measured or detected using our senses or lab instruments (colour, state, pH, melting points)

theoretical properties

explanations of a substances behaviour based on scientific models or concepts (donating or accepting a proton)

what is reliability

considers the way an experiment is preformed. If the experiment is repeated, using the same method. the same result should be obtained. EXAMPLE ON PHONE

what is validity

considers the process used to obtain the results. The process should measure exactly what it is intended to. EXAMPLE IN BOOK

ways to improve reliability

- multiple trials

- precise instrumentation

ways to improve validity

- controlling variables

- calibrated instrumentation

do acids conduct electricity

yes

do bases conduct electricity

yes

do neutral ionic conduct electricity

yes

do neutral molecular conduct electricity

no

what does the bronsted- lowry theory describe

the action of acids and bases during a chemical reaction a hydrogen ion is transferred from an acid to a base during acid base reactions. The hydrogen ion is referred to as a proton. The products of an acid base reaction are a conjugate acid and conjugate base

what does the loss or donation of a hydrogen ion by an acid convert into

convert into a conjugate base

what does hte conjugate base form of thubstance can be recognized as

can be recognized by the loss of a hydrogen ion in its chemical formula

what does the gain or acceptance of a hydrogen ion by a base converts into

converts into a conjugate acid

what does the conjugate acid form of the substance be recognized as

by the gain of a hydrogen ion in its chemical formula

what does one pH unit equal

10x [h3o+]

what does three pH untis equal

10x10x10= 1000x

what is the equivilance point

when the exact theoretical amount of titrant has been added to completely react with the sample

how is an equivilance point measured

measured by a sudden change in observable properties called the endpoint

what is an endpoint

typically a colour change that occurs due to the presence of an indicator

what two dissolved substances does blood contain

carbonic acid (H2CO3) and hydrogen carbonate ion HCO3

what does carbonic acid counter act

the presence of excess base in the blood

what does hydrogen carbonate counteract

the presence of excess acid in the blood

where do other buffer systems exist

in the urine, body proteins, and the blood, all working in similar ways to reduce changes in pH

what do some bodies of water contain

calcium carbonate, a mineral naturally found in chalk, limestone and marble.

what happens to calcium carbonate when dissolved in water

a weal base that can neutralize the addition of small amounts of acid, usually falling as acid rain

what is the equation from thr acid rain

CaCO3 + H2SO4-----> CaSO4+ H2O + CO2

which paretn of canada have low natural buffering capacities

regions of eastern canada have low natural buffering capacity compared to western canada and therefore have become overwhelemed by acid deposition

what is cellular respiration

a process that converts the chemical energy stored in organic molecules (sugars) into energy that cells can use

what are the products of complete combustion

carbon dioxide and water vapour

what are the products of incomplete combustion

carbon monoxide soot and water vapour

what happens during combustion

collisions between the molecules of methane and oxygen result in the formation in new molecules

what are hydrocarbons

organic compounds that contain only carbon and hydrogen atoms.

what are the products of hydrogen combustion reactions

carbon dioxide, water vapour

what does the initial reactant determine

the types of products produced when it combusts (reacts with oxygen)

what will sulfur containg reactant produce

sulfur oxides

what will nitrogen containing reactants produce

nitrogen oxides

what happens to the oxides produced

are released into teh atmosphere are called emmisions (carbon, sulfur, nitrogen)

what does burning carbon compounds like wood ad other forms of biomass result in

production of carbon dioxide

what other natural processes produce carbon dioxide

cellular respiration, forest fires, volcanic eruption, and the weathering of some forms of rock

what is carbon dioxide a component of

the carbon cycle

what is carbon dioxide

greenhouse gas, meaning that it has the ability to absorb thermal energy

what happens by absorbing thermal energy

greenhouse gasses prevent the loss of thermal energy into space and thus, have a direct impact on earths climate

what is a major contributer to current changes in global climate

higher levels of carbon dioxide emmisions

what can carbon dioxide react with

can react with water in the atmosphere to produce carbonic acid

carbonic acid production equation

CO2 + H2O (l) ----> H2CO3

what is carbon monoxide

another oxide of carbon, is a common product of combustion

when is carbon monoxide produced

when the quantity of oxygen is limited during the reaction process

example for carbon monoxide

carbon monoxide is an automobile emission

what can carbon monoxide do

can pose a threat to health

where is sulfur found

found in small quantities within many of the natural resources burned as fuels

what things often contain sulfur

coal, crude oil, natural gas and tar sands often contain sulfur

what does natural gas contain

sulfur but often in the form of hydrogen sulfide (H2S)

what is sour gas

natural gas that contains greater than 1% hydrogen sulfide

what happens when hydrogen sulfide is mixed with water

sour gas is toxic to humans and forms an acidic solution if combine with water

what si sweetening

the process fo removing hydrogen sulfide from natural gas

what is the point of sweetening

to reduce the risk to humans but also reduces the corrosive effects sour gas has on pipelines

equations for oxides of sulfur

H2S + H2O(l) ----> H2SO4

sulfur dioxide plus water

creates sulfurous acod

sulfur dioxide plus oxygen

produces sulfur trioxide

sulfur trioxide plus water

produces sulfuric acid

equation for

sulfur dioxide plus water

= H2SO3

equation for sulfur dioxide plus oxygen

So3

equation for sulfur trioxide plus water

H2SO4

what happens if the temperature of combustion process is hgih enough (abouve 650)

the normal unreactive nitrogen molecule in the air is activated and will reat, often producing nitrogen oxides

what are the oxides produced by combsution reactions

nitrogen monoxide, nitrogen dioxide. These are commonly referred to as NOx compounds

what do nitrogen oxides such as NO react with

atmospheric oxygen to produce nitrogen dioxide

what happens once nitrogen dioxide reacts with water

it can either produce nitrous acid or nitric acid.

what elese can nitrogen dioxide react with

water and oxygen to produce only nitric acid

nitrogen plus oxygen equation

N2 + O2 ---> 2NOx

nitrogen monoxide equation

2NO + O2 ----> 2NO2

nitrogen dioxide plus water equations

NO2 + H2O ---> HNO2/ HNO3

what are natural sources of SO2

- volcanos

- oceans (produces by phytoplankton and algae)

- biological decay

human-made sources of SO2

-coal power plants

- oil refineing

- transportation

natural sources of NO2

- forest fires

- lightning

human-made sources of NO2

- Cars/trucks

- Heavy equipment

- furnaces

- fertilizers (manufactoring and daily use)

Order of most acidic

H2S, HNO3, H2SO3, HNO2, H2CO3

why are NOx emissions higher in urban areas that in rual areas

urban areas have higher industrial processes more automobiles, larger volume of people (population)

gasolinr is a mixture of hydrocarbons, none of which contain nitrogen. Explain how the combustion of gasoline in automobiles can be considered a major source of the production of NOx compounds

the temperature of combustion is so high that it turns atmospheric N2 into NOx

explain how the increased use of combustion processes by society and deforestation could result in a higher level of atmospheric carbon dioxide, a level that cannot be removed by natural processes

combustion increases CO2 and deforestation removes trees that utilize (decrease) CO2. This increases net CO2

where do emissions of carbon dioxidem sulfur oxides or nitrous oxides originate from

originate from human-made processes that involve combustion

what do the chemical equations explain

the chemical equations describe how these emissions are able to react with water to form acid deposition

what is acid deposition

when airborne particles containing acids or acid-forming substances are contained within precipitation or are absorbed directly into parts of earth's surface

what do higher levels of sulfates and nitrates in rainwater result in

result in a higher concentration of hydronium ions in water, resulting in lower pH (more acidic)

what can emissions fro industrial activites carry

can carry sulfur dioxide and other substances great distances

what is a major factor to determine how long emissions will stay in the atmosphere

is how quickly they come into contact with other materials in the enviroment,

what are the two ways that acid can be depositied or transported

by wet and dry deposition

wet deposition

emissions (gases or particulates)

that react with water, etc are then dissolved in water droplets and fall to the ground as rain snow fog or sleet

dry deposition

continuos process in dry westher, emissions are transported by winds, fall to the ground through gravitational settling

where in alberta has the most pollution from emissions

alberta has a dry climate so it is estimates that most of the pollution from emissions in alberta occurs in the form of dry deposition

what does the term acid rain describe

excessive amount of acidity within precepitation (wet deposition)

in many areea of the world, what is acid rain adue from

acid deposition si largely due to emissions from human activites

what do wind patterns like the jet stream ( narrow, fast flowing band of strong wind in the upper atmosphere) do

provide a way for acid deposition to be transported wha

what does the predictability of wind provvide

a way to trace the path of acid deposition back to uts source

in canada wind....

in canada, the prevailing winds called the westerlies, come from the west and travel to the east. This means that acid deposition is most likely to be depositied where the wind carries it

what does acid deposition impact

a variety of enviromental and ecological systems

water system effecgt from ad

as happens in water, decreases the pH make the water more acidic

plant system effect from ad

- direct damages to their leaves from the (acid rain)

- damage to chloroplasts

- chlorosis=decrease in the plants abilityu to do photosynthesis in leaves due to decrease in chlorophyll

soil system effect from ad

acidic H2O in soil can produce H+ ions which can displace essential nutrients lake Ca2+, Mg+ and K+= they are washed away before plants can absorbe them. Heavey metals are acid soluble, start to dissole and is toxic to plants

what can the acidification of soil can cause

helful metal ions, such as magnesium and calcium, to be availabile to plants.