chem]

Question 1

how would you extract silver

Answer 1

mining it as silver

Question 2

how would you extract iron

Answer 2

displacement with carbon

Question 3

why was [insert group 1 2 or 3 metal] not extracted until 1800s while gold has been extracted for thousands of years?

Answer 3

• 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]

Question 4

what type of rection involves a displacement of ores?

Answer 4

a redox reaction

Question 5

what are bases

Answer 5

insoluble metal hydroxides and metal oxides

Question 6

what are alkalis?

Answer 6

soluble metal hydroxides

Question 7

what are the products of reacting a acid with a metal carbonate?

Answer 7

salts, water and carbon dioxide

Question 8

what does hydrocholric acids produce

Answer 8

chlorides

Question 9

what do nitric acids produce

Answer 9

nitrates
(NO₃)⁻

Question 10

what do sulfuric acids produce

Answer 10

sulfates
(SO₄)²⁻

Question 11

what do chlorides produce

Answer 11

Cl⁻

Question 12

Why is the sulfuric acid heated in stage 1?

Answer 12

To increase the rate/speed of the reaction

Question 13

How would you know when the copper(II) oxide is in excess in stage 2

Answer 13

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

Question 14

Why is the mixture filtered in stage 3

Answer 14

to remove (unreacted/excess) copper(II) oxide

Question 15

Why do crystals form when the hot saturated solution is cooled in stage 5?

Answer 15

copper(II) sulfate/the crystals are less soluble in cold water (than in hot water) [

Question 16

Suggest a suitable method of drying the crystals.

Answer 16

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

Question 17

Explain, in terms of ions and molecules, what happens when any acid reacts with
any alkali.

Answer 17

• Hydrogen ions/H+ in the acid [1]
• React with hydroxide ions OH- in the alkali [1]
• To produce water [1]

Question 18

what is a dm^3 in terms of cm^3

Answer 18

1 dm^3 = 1000cm^3

Question 19

give four characteristics of a titration table that must b maintained to insure that it is valid

Answer 19

• 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

Answer 20

1. Use the pipette to measure 25cm3
   of sodium hydroxide into the conical flask.
2. Place the conical flask on a white tile.
3. Fill the burette with sulphuric acid using a funnel.
4. Record the initial reading of acid in the burette.
   - Make sure to always take readings from the bottom of the meniscus.
5. Add a 5 drops of indicator in this case phenolphthalein to the conical flask.
6. Slowly open the burette tap while swirling the conical flask.
7. Add acid drop-by-drop near the endpoint.
   - At this point the colour will start to change slightly.
8. Close the burette when a colour change occurs in phenolphthalein.
   - The solution turns from pink to colourless.
9. Record the final reading of acid in the burette and calculate the titre. This is the volume
   of acid used to neutralise the alkali.

Question 21

what is the formula to measure concentration or moles or volume

Answer 21

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)

Question 22

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