Precipitation color and precipitate of junior high chemical substances

cucuo

cuso4cuso4

5h2ocu(oh)2

CuSO4 solution.

Red, black.

White Blue.

Blue Blue.

fefe2o3

Fe3O4Fe2+ solution.

Fe3+ solution.

fe(oh)3

Silvery white. Reddish-brown.

Black. Light green.

Yellow. Sorrel.

Memories of precipitation.

In the third stage of junior high school, the precipitation with the most exposure can be summarized as "six white", "one blue" and "one reddish brown".

Six white "caco3

ag2co3

baco3baso4

agclal(oh)3

mg(oh)2

Soluble in dilute nitric acid, and produces gas.

Insoluble in dilute nitric acid.

Soluble in dilute nitric acid, no gas.

One blue" Cu(OH)2 "One reddish-brown" Fe(OH)3

nh4cl+

koh=kcl+nh3↑+h2o

Produces a gas that turns the wet litmus paper blue.

NH4NO3+NaOH = nano3+NH3 +H2O produces a gas that turns the wet litmus paper blue.

It should be used to detect ammonium ions in solutions.

agno3+nacl

agcl↓+na

NO3 white is insoluble in the precipitation of dilute nitric acid (similar reaction to other chlorides) and is used to test chloride ions in solutions.

bacl2na2so4

baso4↓+2nacl

White precipitates that do not dissolve in dilute nitric acid (similar reactions to other sulfates) should be used to test sulfate ions.

cacl2+na2co3=

caco3↓+2nacl

There is a white precipitate generated.

MgCl2+Ba(OH)2=BaCl2+Mg(OH)2 is formed with a white precipitate.

Ca(OH)2+Na2CO3=CaCO3 +2NaOH has a white precipitate to form.

Industrial caustic soda, laboratory caustic soda in small quantities.

Ba(OH)2+Na2CO3=BaCO3 +2NaOH has a white precipitate generated.

ca(oh)2+k2co3=caco3↓

2koh has a white precipitate generated.

FeCl3+3NaOH = Fe(OH)3 +3NaCl solution fades yellow and has reddish-brown precipitate.

AlCl3+3NaOH = Al(OH)3 +3NaCl has a white precipitate.

mgcl2+2naoh

mg(oh)2↓+2nacl

cucl2+2naoh

cu(oh)2↓+2nacl

The blue color of the solution fades, and a blue precipitate is formed.

The eight major precipitates of junior high school chemistry are:

AGCL (silver chloride), BaSO4 (barium sulfate), CaCO3 (calcium carbonate), BaCO3 (barium carbonate), Al(OH)3 (aluminum hydroxide), MG(OH)2 (magnesium hydroxide), Cu(OH)2 (copper hydroxide), Fe(OH)3 (iron hydroxide).

Silver chloride and barium sulfate are insoluble in acids, and the other six major precipitates are soluble in acids.

Among them, AgCl, BaSO4, CaCO3, BaCO3, Al(OH)3 and Mg(OH)2 are white precipitates, Cu(OH)2 are blue flocculent precipitates, and Fe(OH)3 are reddish-brown precipitates. Silver chloride and barium sulfate are insoluble in acids, calcium carbonate and barium carbonate are soluble in acids and have bubbles, magnesium hydroxide, aluminum hydroxide, iron hydroxide and copper hydroxide are soluble in acids without bubbles.

Precipitation is typically found in metathesis reactions, where copper hydroxide is typically formed by the reaction of copper sulfate and sodium hydroxide.

1. Red solid: copper, iron oxide;

2. Green solid: basic copper carbonate;

3. Blue solid: copper hydroxide, copper sulfate crystals;

4. Purple-black solid: potassium permanganate;

5. Light yellow solid: sulfur;

6. Colorless solids: ice, dry ice, diamond;

7. Silvery-white solid: silver, iron, magnesium, aluminum, mercury and other metals;

8. Black solid: iron powder, charcoal, copper oxide, manganese dioxide, ferric tetroxide, (carbon black, activated carbon);

9. Reddish-brown solid: iron hydroxide;

10. White solid: sodium chloride, sodium carbonate, sodium hydroxide, calcium hydroxide, calcium carbonate, calcium oxide, copper sulfate, phosphorus pentoxide, magnesium oxide.

In the study of junior high school chemistry, there are a total of 8 precipitates. They are: copper hydroxide, iron hydroxide, calcium carbonate, silver carbonate, barium carbonate, magnesium hydroxide, barium sulfate and silver chloride.

Precipitation color: blue: copper hydroxide.

Reddish-brown: iron hydroxide.

White: calcium carbonate, silver carbonate, barium carbonate, magnesium hydroxide, barium sulfate and silver chloride.

The equation formed by precipitation:

Copper hydroxide: CuSO4 + 2NaOH = Na2SO4 + Cu(OH)2

Iron hydroxide: FeCl3 + 3NaOH = Fe(OH)3 + 3NaCl

Calcium carbonate: Ca(OH)2 + Na2CO3 = CaCO3 + 2NaOH

Silver carbonate: 2agno3 + na2co3 = ag2co3 + 2nano3

Barium carbonate: NaHCO3 (a small amount) + BA(OH)2 = BAC3 + NaOH + H2O

Magnesium hydroxide: MgCl2 +2NaOH = Mg(OH)2 +2NaCl

Barium sulfate: Ba(OH)2 + Na2SO4 = BaSO4 + 2NaOH

Silver chloride: 2agNO3 + MGCL2 = MG(NO3)2+2AGCL

1: Solid.

or crystals).

mg,fe,zn,ag silvery-white.

P (white), P2O5, CAO, MGO, KCLO3, CuSO4, NaCl white.

C, Cuo, Mno2, Fe3O4 Black.

Cu, P (red), Fe2O3 red.

Spot color KMNO4 violet.

Black cuso4

Copper hydroxide (blue) Cuoh copper carbonate copy (blue) CuSO4 barium sulfate (white) baso4 barium carbonate (white) baCO3 calcium carbonate (white) CaCO3

Magnesium hydroxide (white) mg(OH)2

Aluminium hydroxide (white) Al(OH) 3

Manganese carbonate (white), mnCO3, manganese dioxide (black), mno2, zinc hydroxide (white), ZN(OH)2, zinc carbonate (white), ZNCo3, iron hydroxide (reddish-brown), Fe(OH)3, ferrous hydroxide (green), Fe (OH)2, silver chloride (white), AGCL, silver carbonate (white), Ag2CO3

Silver chloride white, potassium permanganate purple, copper oxide black, iron hydroxide reddish-brown, sulfate shell white, copper hydroxide blue, iron chloride brown, sodium peroxide yellow, sulfur element light yellow.

Copper carbonate is blue-green, other carbonates are white.

Iron hydroxide is reddish-brown, copper hydroxide is blue, ferrous hydroxide, magnesium hydroxide, aluminum hydroxide is white barium sulfate, and silver nitrate is white (insoluble in acid).

Iron salt solution yellow.

The ferrous salt solution is light green.

Copper salt solution blue.

These are junior high school ones.

Copper hydroxide: blue iron hydroxide: reddish-brown ferrous hydroxide: white flocculent precipitation, quickly turning gray-green in the air.

genus, which eventually became reddish-brown barium sulfate, silver chloride, calcium carbonate, barium carbonate, silver carbonate, silver sulfate, aluminum hydroxide: white silver iodide: yellow, silver bromide:

Light yellow Sulphur: Yellow , Potassium permanganate: Purple Copper oxide:

Black silver hydroxide: white, quickly decomposes into silver oxide when exposed to water, black precipitate solution color: iron ions:

Yellow ferrous ions: light green copper ions: blue chromogenic reactions:

Ferrric ions and phenol: purple concentrated nitric acid and protein: yellow iodine meets starch:

In addition, blue: flame color: potassium:

Purple Sodium: Yellow Copper: Green Calcium:

Brick-red copper hydroxide and polyhydroxyl alcohol (glucose): reddish blue.

White precipitate: AGCl, AG2CO3, AG2SO4, BAC3, BASO4, CAC3, MG(OH)2

Blue precipitate: Cu(OH)2

Reddish-brown precipitate: Fe(OH)3

There are a lot of these, but there are only a few to master in junior high school.

The common precipitates in junior high school are basically white, such as calcium carbonate, barium carbonate, silver chloride, barium sulfate, and lime milk (calcium hydroxide) are the five common white precipitates in junior high school; In addition, silver bromide is a pale yellow precipitate, and silver iodide is a yellow precipitate, which I forgot to talk about in junior high school. A special point is that copper hydroxide is a blue flocculent precipitate, and strong iron oxide is a brownish-red precipitate.

The two major acid-insoluble precipitates are silver chloride (including silver bromide, silver iodide, of course) and calcium sulfate precipitate, which are originally aimed at water-insoluble ......

Insoluble in water: (not marked white).

Fe(OH)2, Fe(OH)3 brick red, mg(oh)2, cu(oh)2 blue, baso4, agcl, mgso4, baco3, cuco3 blue.

Among them, barium sulfate and silver chloride are insoluble in acids.

In general, alkalis are insoluble in water except sodium hydroxide, calcium hydroxide (slightly soluble), barium hydroxide and potassium hydroxide; Ammonium, potassium, sodium, and nitrate are all soluble; The only insoluble acids are barium sulfate and silver chloride;

The slightly soluble salts are mainly calcium sulfate and magnesium carbonate, and the insoluble salts are mainly calcium carbonate. Remember this, junior high school is enough.

Learn to summarize on your own, otherwise you'll be in trouble later!

Blue: Contains copper ions. Such as: copper hydroxide, etc.

Green: Containing ferrous ions: such as: ferrous hydroxide, ferrous carbonate, etc.

Reddish-brown: containing iron ions: such as: iron hydroxide, iron carbonate, etc.

White: barium carbonate, silver chloride, barium sulfate, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, manganese hydroxide, zinc hydroxide, manganese carbonate, zinc carbonate, etc.

Brick red: cuprous oxide, etc.

copper hydroxide, blue flocculent; iron hydroxide, reddish-brown; ferrous hydroxide, white; Silver chloride, barium sulfate white; calcium carbonate, white;

ferrous disulfide, yellow; Sulfur, yellow.

The white precipitate is: barium carbonate, calcium carbonate, silver chloride, barium sulfate, the blue precipitate has: copper hydroxide, and the reddish-brown precipitate has: iron hydroxide, etc.

Copper sulphate (blue), iron hydroxide (reddish brown), silver chloride, barium sulphate, calcium carbonate, barium carbonate, magnesium hydroxide (white).