Chemistry Paper 1 #1 Flashcards
What is electrolysis?
Electrolysis is a process that uses electric current to decompose ionic compounds into their elements.
Define anode and cathode in electrolysis.
Anode is the positive electrode where oxidation occurs, and cathode is the negative electrode where reduction occurs.
What products are formed at the anode and cathode during electrolysis of aqueous solutions?
At the anode, oxygen or halogens form (if halide ions are present). At the cathode, hydrogen forms if the metal is more reactive than hydrogen.
What is the reactivity series and its importance?
The reactivity series is a list of metals ordered by reactivity. It helps predict how metals will react with water, acids, and other elements.
What are redox reactions?
Redox reactions involve oxidation (loss of electrons) and reduction (gain of electrons) occurring simultaneously.
Define oxidation and reduction in terms of oxygen.
Oxidation is the gain of oxygen, and reduction is the loss of oxygen.
What happens when metals react with acids?
Metals above hydrogen in the reactivity series react with acids to produce a salt and hydrogen gas.
Describe the general equation for a neutralisation reaction.
Acid + Base -> Salt + Water
What is the pH scale?
The pH scale measures how acidic or basic a solution is, ranging from 0-14, with 7 being neutral.
What distinguishes strong acids from weak acids?
Strong acids completely dissociate in water, while weak acids only partially dissociate.
What is an exothermic reaction?
An exothermic reaction releases energy to the surroundings, usually indicated by a rise in temperature.
What is an endothermic reaction?
An endothermic reaction absorbs energy from the surroundings, usually indicated by a fall in temperature.
What are bond energy calculations used for?
Bond energy calculations are used to determine if a reaction is exothermic or endothermic by comparing the energy required to break bonds vs. the energy released when bonds form.
How do you calculate energy changes using bond energies?
Energy change = Sum of bond energies of bonds broken - Sum of bond energies of bonds formed.
What is a displacement reaction?
A displacement reaction occurs when a more reactive metal displaces a less reactive metal from a compound.
What is the Daniell cell?
A type of electrochemical cell where zinc and copper electrodes create a voltage through a redox reaction in an electrolyte solution.
Describe the function of a hydrogen fuel cell.
In a hydrogen fuel cell, hydrogen and oxygen react to produce water, releasing electrical energy.
List one advantage and one disadvantage of hydrogen fuel cells.
Advantage: Less pollution. Disadvantage: Hydrogen storage is challenging and potentially dangerous.
What is activation energy?
Activation energy is the minimum energy required for a reaction to occur by breaking initial bonds.
What is a spectator ion?
A spectator ion is an ion that does not participate in the actual chemical reaction and remains unchanged.
Explain how the reactivity series is used in predicting reactions.
Metals higher in the series can displace metals lower in the series from compounds, and more reactive metals will react more vigorously.
