chemical changes topic Flashcards
(11 cards)
what reaction do these things have with water?
potassium
sodium
lithium
calcium
Magnesium
zinc
iron
copper
gold
Potassium, sodium, lithium : violent
calcium: fast
magnesium: very slow
Zinc : no reaction
iron : rusts slowly
Copper, gold : no reaction
what are these things reactions to dilute acids?
potassium
sodium
lithium
calcium
magnesium
zinc
iron
copper
gold
Potassium, sodium, lithium : violent
calcium, magnesium : rapid
Zinc, Iron : slow
copper gold : no reaction
what is formed when a metal reacts with water ?
a metal hydroxide
what do alkalis in alkaline solutions produce
hydrogen ions +h
what do acids in acidic solutions produce
hydrogen ions -oh
method to carry out a titration
1) use a pipette and a pipette filler to add a measured volume of sodium hydroxide solution to a clean conical flask
2) add a few drops of indicator and put the conical flask on a white tile
3) fill the burette with hydrochloride acid and note the starting volume
4) slowly add the acid from the burette to the alkali in the conical flask, swirling to mix in
5) stop adding acid when end point is reached ( when the indicator first permanently changes colour) note the final volume reading
repeat the steps until 1 to 5 until concordant titres are obtained. More accurate results are obtained if you add drops of acid at the end.
What is electrolysis?
Electrolysis is a chemical process that uses electricity to break down compounds into their constituent elements.
True or False: Electrolysis can only occur in aqueous solutions.
False: Electrolysis can occur in both aqueous solutions and molten states.
Fill in the blank: The positive electrode in electrolysis is called the __________.
anode
Which of the following is produced at the cathode during the electrolysis of water? a) Oxygen b) Hydrogen c) Chlorine
b) Hydrogen
What is the role of the electrolyte in electrolysis?
The electrolyte conducts electricity and allows ions to move, facilitating the chemical reaction.
