test Flashcards
Fill in the gaps
_________
————-
————
sodium carbonate
calcium chloride
iron (III)
Explain two mistakes in the paper chromatography
start line drawn in ink
ink will dissolve into the paper
The paper is placed too deep into the solvent
the ink will wash away
What does this tell you about the black food colouring j
It contains A and E
it contains an unknown substance
Calculate RF value
31
13
13/31
= 0.42
Which food colour could be food colour C
fast red
it has the closest RF value to food colour C (0.42)
Give one advantage
it is more efficient/ quicker
Titration practical
Using a pippette, measure and add a fixed volume of 25cm3 of sodium hydroxide into a conical flask
add a few drops of indicator
Place the flask onto a white tile
Fill the biurrete with HCL
Place the flask under the biurrete and slowly add drops of HCl into the flask
Swirl/ shake to make sure it’s mixed
Once you see a colour change, read the biurette to see the concentration
Repeat with HCL B
repeat to find mean/ spot anomalies
Describe how the student could identify the gas
Bubble gas through limewater
turns cloudy
Is the students conclusion correct
No
red flame could be calcium
Aluminium ions dissolve in NaOH
Is the student correct
yes
silver nitrate forms a white precipitate
Name one modern instrumental method
Instrumental analysis ( wrong)
What is the meaning of more sensitive
Detect smaller ions
What is the meaning of more sensitive
can detect better (wrong
Why do elements in group 1 have similar properties
1 electron on its outer shell
Why does the reactivity increase
outer electron gets further away
electrostatic attraction between positive nucleus and negative electron gets stronger
