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Chemistry Chapter 4 Chemical Changes
Study this set o nline at: https://www
...
co m/flashcards/chemistry-chapter-4chemical-changes-10 9 9 8 48 5
Some metal oxi des/hydroxi des di ssol ve i n water
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Reacti ons of aci ds

E ven bases that don’t di ssol ve i n water take part i n neutral i sati on reacti ons
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Less reacti ve metal s such as copper, z i nc and i ron don’t
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What i s a redox reacti on?

I ron has oxi di sed
H ydrogen has been reduced

T hey are redox reacti ons
...

What i s a di spl acement reacti on and what are the rul es?

T he metal i on gai ns el ectrons
T he metal atoms l oses el ectrons

What are i oni c equati ons?

T hey show onl y the parti cl es of a reacti on that are reacti ng and thei r products
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Chl ori ne- bl eached damp bl ue l i tmus paper whi te
T ests f or gases

H ydrogen- Squeaky pop test wi th l i ghted spl i nt
Oxygen- Rel i ghts a gl owi ng spl i nt

4OH - > O2 + 2H 2O + 4e-

What i s the equati on f or the hal f equati on f or the anode i f a hal i de i on i sn’t

Or 4OH - - 4e- > O2 + 2H 2O

present?

Oxi dati on
Is
Loss
What i s oxi dati on and reducti on? I n terms of el ectrons and oxygen
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Chemistry Chapter 4 Chemical Changes
Study this set o nline at: https://www
...
co m/flashcards/chemistry-chapter-4chemical-changes-10 9 9 8 48 5
Separati ng a metal f rom i ts oxi de i s a reducti on reacti on
Some metal s can be extracted by reducti on wi th carbon (l ess reacti ve metal s eg
H ow can metal s be separated f rom thei r oxi des?

z i nc, i ron, copper)

Whi ch metal s?

Carbon oxi di ses removi ng the oxygen f rom the metal oxi de
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Aci ds produce H + i ons (protons) i n water (i oni se)
Strong aci ds i oni se compl etel y i n water
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N on reversi bl e reacti on
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Reversi bl e reacti on
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Aci ds f orm H + i ons i n water
A base i s a substance wi th pH of greater than 7
N eutral i sati on reacti ons

Al kal i i s a base that di ssol ves i n water f ormi ng hydroxi de i ons i n water
Aci d + base > sal t + water
H ydrogen i ons + hydroxi de i ons > H 2O
Can be used to cal cul ate concentrati on by ti trati on
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pH wi l l decrease wi th i ncreasi ng aci d concentrati on

M easure of how aci di c or al kal i a substance i s,
Low pH aci di c
H i gh pH al kal i

What does pH show and how can i t be measured?

Water i s neutral - pH 7
Uni versal i ndi cator- red, green, purpl e
pH probe- numeri cal val ue so consi dered more accurate

M easure of concentrati on of hydrogen i ons
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E l ectrol ysi s- separati ng compounds wi th el ectri ci ty
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T hey f orm the uncharged el ement and are

What substances make sui tabl e el ectrodes?

di scharged f rom el ectrol yte
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Where do metal and non metal i ons move to i n el ectrol ysi s?

M etal i ons- reduced at cathode
N on metal i ons- oxi di sed at anode

Chemistry Chapter 4 Chemical Changes
Study this set o nline at: https://www
...
co m/flashcards/chemistry-chapter-4chemical-changes-10 9 9 8 48 5
H ave to f actor i n i ons i n water
At the cathode, i f hydrogen i ons and metal i ons are present, hydrogen gas wi l l be
produced i f metal f ormed i s more reacti ve than hydrogen eg sodi um
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At the anode i f hydroxi de i ons and hal oed i ons are present eg Cl -, mol ecul es of
hal ogen gas f orm
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H al f equati on at anode- 2O2 > O2 + 4eWhat are the hal f equati ons f or el ectrol ysi s of al umi ni um oxi de and why i s

Cathode- Al 3+ + 3e- > Al

cryol i te added?

Cryol i te i s added to l ower mel ti ng poi nt of al umi ni um oxi de and theref ore save
energy
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T he speed of a reacti on i s i ndi cated by the rate at whi ch bubbl es of hydrogen
are gi ven of f
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Reacti vi ty can al so be measured by temperature change over a set ti me peri od
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Gentl y warm di l ute aci d usi ng Bunsen burner, turn of f Bunsen burner
Add i nsol ubl e base unti l no more reacts

H ow can sol ubl e sal ts be made usi ng an i nsol ubl e base?

F i l ter out excess sol i d f rom sol uti on to get sal t sol uti on
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Stop heati ng and l eave to cool
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Crystal l i sati on

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