slop 5 Flashcards
State the colour of a strong acid in universal indicator.
red
State the colour of a neutral in universal indicator.
green
State the colour of an alkali in universal indicator.
purple
Give three examples of acids. Give their formula.
Hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3)
Name some examples of alkalis
Sodium hydroxide (NaOH) Potassium hydroxide (KOH) and Lithium hydroxide (LiOH).
What will happen to the pH of an alkali if an acid is added to it?
pH decreases.
What is electrolysis?
The splitting of an ionic compound in to its elements using electricity.
What is the name of the substance that is electrolysed?
Electrolyte
What state must the compound be in during electrolysis and why?
Molten or dissolved in solution. Ions are free to move about within the liquid or solution.
What are the disadvantages of electrolysis?
Requires lots of energy to melt ionic compounds, usually from fossil fuels (very expensive)
What is the name of the positive electrode?
Anode
What is the name of the negative electrode?
cathode
What ions go to the positive electrode?
Negative
What ions go to the negative electrode?
positive
Predict the products if lead bromide undergoes electrolysis.
Lead and bromine
Predict the products if tin chloride undergoes electrolysis.
tin and chlrorine
Predict the products if copper chloride undergoes electrolysis.
Copper and chlorine
Predict the products if sodium fluoride undergoes electrolysis.
Sodium and fluorine
What is added to aluminium oxide to reduce its melting point?
Cryolite
Predict the products if aluminium oxide undergoes electrolysis.
aluminium and oxygen
Explain why the positive electrode must be replaced.
The oxygen reacts with the carbon electrode to produce carbon dioxide.
What does aqueous mean?
Dissolved in water.
What ions are present in NaCl(aq)?
Na+ Cl- H+ OH-
Which would be produced at the negative electrode; hydrogen or sodium?
Hydrogen (less reactive than sodium)
