chemical tests

Question 1

what is the chemical test for oxygen?

Answer 1

glowing splint- relights

Question 2

whats the test for co2

Answer 2

bubble through lime water (caOH) - goes cloudy white precipitate forms

Question 3

whats test for hydrogen?

Answer 3

lit splint in gas - squeaky pop

Question 4

whats chemical test for ammonium

Answer 4

damp red limits paper-turns blue

Question 5

whats chemical test for chlorine?

Answer 5

damp red limit paper- bleaches white

Question 6

how do you make oxygen?

Answer 6

2h2o2(using MnO2 as catalyst)=o2+2h2o

Question 7

how do you make hydrogen?

Answer 7

metal+acid=salt+hydrogen

Zn+2HCl = ZnCl2+H2

Question 8

how do you make co2?

Answer 8

CaCo3 +2HCl=CaCl2 +co2+h2o

Question 9

how do you do a flame test?

Answer 9

take a nichrome/ platinum wire and dip it in concentrated Hcl acid then dip into small amount of solid and place wire in edge of roaring flame

Question 10

what colour does sodium turn in flame test?

Answer 10

yellow

Question 11

what colour does calcium turn in flame test?

Answer 11

orange red

Question 12

what colour does copper turn in flame test?

Answer 12

blue green

Question 13

what colour does potassium turn in flame test?

Answer 13

lilac

Question 14

what colour does lithium turn in flame test?

Answer 14

red

Question 15

how else can you identify cations?

Answer 15

cations= positive ions , sodium hydroxide solution is added to metal solution and forms a precipitate when mix together

Question 16

what observations are there when naoh is added to cu?

Answer 16

forms blue solid precipitate

Question 17

what observations are there when naoh is added to fe2+?

Answer 17

murky green solid precipitate

Question 18

what observations are there when naoh is added to fe3+?

Answer 18

rusty brown red solid precipitate

Question 19

what observations are there when naoh is added to nh4?

Answer 19

fumes turn red limits paper blue

Question 20

how do you test for anions?

Answer 20

anions=negative ions

halide ions add 1cm3 of AgNO3 silver nitrate to equal volume of halide ion

Question 21

what observations are there when AgNO3 is added to cl?

Answer 21

milky white precipitate AgCl

Question 22

what observations are there when AgNO3 is added to br

Answer 22

cream precipitate AgBr

Question 23

what observations are there when AgNO3 is added to i

Answer 23

pale yellow precipitate AgI

Question 24

How do you test for the sulphate ion?

Answer 24

add few drops of BaCl2 containing sulphate ion

white precipitate formed BaSO4

Question 25

How do you test for a carbonate ion?

Answer 25

add dilute Hcl to carbonate starts fizzing and pass resulting co2 through limewater should turn cloudy

Question 26

how do you test for water?

Answer 26

anhydrous copper sulphate added turns from white to blue | cobalt chloride paper blue to pink

Question 27

how do you test for impurities in water?

Answer 27

pure substances = pure melting point | impure substances = higher boiling point