chemical tests 4.6 Flashcards
test for hydrogen
squeaky pop
test for oxygen
relights a glowing splint
test for water
anhydrous copper sulfate changes from white to blue
test for pure water
bp is 100 degrees
test for carbon dioxide
bubble through lime water, clear to cloudy
test for chlorine
damp blue litmus, blue to white
test for ammonia
red litmus, red to blue
what are cations
positive ions
how to conduct a flame test
dip a piece of platinum wire into hydrochloric acid
dip the wire into a sample of solid or solution
place the tip of the wire into Bunsen flame
red flame
lithium Li+
yellow flame
sodium Na+
lilac flame
potassium K+
orange/red flame
calcium Ca2+
blue/green flame
copper Cu2+
what is sodium hydroxide used to test for
Cu2+, Fe2+, Fe3+
how to conduct a sodium hydroxide test
dissolve the sample in water
add a few drops of NaOH
blue precipitate (NaOH)
Cu2+
green precipitate (NaOH)
Fe2+
brown precipitate (NaOH)
Fe3+
how does a sodium hydroxide test work
if one of the ions is present, a metal hydroxide precipitate forms
how to conduct an ammonium test
dissolve the sample in water
add some NaOh and warm it
test the gas with damp red litmus paper
red to blue
what are anions
negative ions
what is the test for halide ins
silver nitrate test
how to conduct the silver nitrate test
dissolve the sample in water
add nitric acid
add silver nitrate
if halide ions are present a precipitate forms
what does the silver nitrate test test for
Cl-, Br-, I-
white precipitate (AgNO3)
Cl-
cream precipitate (AgNO3)
Br-
yellow precipitate (AgNO3)
I-
how to test for carbonates
add hydrochloric acid, look for effervescence
if there is effervescence, bubble through lime water
turns limiter cloudy CO32-
how to test for carbonates
add hydrochloric acid, look for effervescence
if there is effervescence, bubble through lime water
turns limiter cloudy CO32-
how to test for sulfates
add hydrochloric acid, look for effervescence
if there is no effervescence, add Barium Chloride solution
white precipitate will form if sulfates are present
sulfates
So4 2-
carbonates
CO3 2-
