Chemical changes Flashcards
What is a pH scale?
measures how acidic or alkaline a solution is.
The lower the pH means what?
The more acidic
The higher the pH means what?
The more alkaline
What pH does a Neutral substance have?
pH7
How can you measure the pH of a solution?
Universal indicator
How can you measure the pH electronically?
pH probe which is more accurate than an indicator
What ions do Acids produce in aqueous solutions?
Hydrogen ions (H+)
H+ + CL- form what?
HCI
What are bases?
They are chemicals with a pH greater than 7 which can neutralise acids and produce salt and water
What is a alkali?
It is a base that dissolves in water to forma solution greater than 7.
Name an example of bases.
sodium hydroxide
What ions do Alkali’s from in water?
OH- ions
What does a green colour show on a pH scale
Neutral
What do colours towards red show on a pH scale?
Show acidic solutions
What do colours towards Purple show on a pH scale?
Alkaline solutions
What do acids have a pH of?
Less than 7
What are solutions with a pH of 7 show?
It is Neutral
What do Alkaline’s have a pH of?
8-14
What is the Neutralization equation?
Acid + base - Salt + water
What is the symbol equation for Neutralization?
H+ + OH- - H2O
In aqueous solutions what do acid molecules do?
They ionize (split) and release H+
What are strong acids?
They fully ionize in aqueous solutions.
Name 3 strong acids?
Sulfuric acid
Hydrochloric acid
Nitric acid
How can you tell a reaction is fully ionized (strong acid)
Arrow goes in one direction
What are weak acids?
They do not fully ionize in solution
How can you tell a reaction has not fully ionized(Weak acid)?
Reversible arrow showing it is a reversible reaction.