chem] Flashcards
how would you extract silver
mining it as silver
how would you extract iron
displacement with carbon
why was [insert group 1 2 or 3 metal] not extracted until 1800s while gold has been extracted for thousands of years?
- Sodium is very reactive so found in compounds [1]
- Sodium is difficult to extract or the technology was not available to extract it. [1]
- Gold is found in native form or found as the metal. [1]
- No extraction process needed for gold. [1]
what type of rection involves a displacement of ores?
a redox reaction
what are bases
insoluble metal hydroxides and metal oxides
what are alkalis?
soluble metal hydroxides
what are the products of reacting a acid with a metal carbonate?
salts, water and carbon dioxide
what does hydrocholric acids produce
chlorides
what do nitric acids produce
nitrates
(NO₃)⁻
what do sulfuric acids produce
sulfates
(SO₄)²⁻
what do chlorides produce
Cl⁻
Why is the sulfuric acid heated in stage 1?
To increase the rate/speed of the reaction
How would you know when the copper(II) oxide is in excess in stage 2
it stops disappearing [1]
OR
there is a (black) suspension/solid/copper(II) oxide [1]
OR
the mixture/it turns cloudy/black [1]
IGNORE crystals
Why is the mixture filtered in stage 3
to remove (unreacted/excess) copper(II) oxide
Why do crystals form when the hot saturated solution is cooled in stage 5?
copper(II) sulfate/the crystals are less soluble in cold water (than in hot water) [
Suggest a suitable method of drying the crystals.
on filter paper/kitchen towel/tissue paper [1]
OR
leave / in a warm place / in the sun / on a radiator / near a window / in a
(warm/drying) oven/dessicator
Explain, in terms of ions and molecules, what happens when any acid reacts with
any alkali.
- Hydrogen ions/H+ in the acid [1]
- React with hydroxide ions OH- in the alkali [1]
- To produce water [1]
what is a dm^3 in terms of cm^3
1 dm^3 = 1000cm^3
give four characteristics of a titration table that must b maintained to insure that it is valid
- all values in the top section must be rounded to 2dp where second dp is either 0 or 5
- only the values that are concordant
- Use the pipette to measure 25cm3
of sodium hydroxide into the conical flask. - Place the conical flask on a white tile.
- Fill the burette with sulphuric acid using a funnel.
- Record the initial reading of acid in the burette.
- Make sure to always take readings from the bottom of the meniscus. - Add a 5 drops of indicator in this case phenolphthalein to the conical flask.
- Slowly open the burette tap while swirling the conical flask.
- Add acid drop-by-drop near the endpoint.
- At this point the colour will start to change slightly. - Close the burette when a colour change occurs in phenolphthalein.
- The solution turns from pink to colourless. - Record the final reading of acid in the burette and calculate the titre. This is the volume
of acid used to neutralise the alkali.
what is the formula to measure concentration or moles or volume
CaVa/CbVb=na/nb
where na= number of moles of acid
nb = number of moles of base
Ca = concentration of acid
Cb = concentration of base
Va=average volume of acid from titration
Vb = volume of base(volumeof pipette)
https://www.brainscape.com/l/dashboard
