pH, Acids And Bases Flashcards
What happens to the solution as the ph value decreases?
The solution is becoming more acidic
What happens to the solution as the ph value increases?
The solution becomes more alkaline
Corrosive substances usually have what?
A very low or high ph
Which substances conduct electricity?
Metals, ionic compounds, ionising covalent compounds, dissolved ionic compounds (aq) and liquid ionic compounds
Which substances don’t conduct electricity?
Non-metals, covalent compounds and solid ionic compounds
Why do acid solutions have a ph less than 7
Because they have a higher concentration of Hydrogen ions than hydroxide ions when compared to pure water
Why do alkaline solutions have a ph greater than 7?
Because they contain a higher concentration of hydroxide ions than hydrogen ions when compared to pure water
What do non-metal oxides produce?
Non-metal oxides which dissolve in water increases the concentration of hydrogen ions (compared to pure water) and therefore produce acidic solutions
What do metal oxides produce?
Metal oxides which dissolve in water increase the hydroxide concentration (compared to pure water) and therefore produces alkali solutions
Acid reacts with metals to form what?
Acids react with metals to form a salt and hydrogen gas
Acid reacts with carbonates to form what?
Acids react with carbonates to form a salt, water and carbon dioxide gas
What are the general equations for reactions of acids?
Metal + acid forms salt + hydrogen
Metal carbonate + acid forms salt + carbon dioxide + water
Metal oxide + acid forms salt + water
Metal hydroxide + acid forms salt + water
Why does the ph of an acid move towards 7?
Because the hydrogen ion concentration is being reduced as they react to form water molecules
Why does the ph of an alkali move towards 7?
Because the hydroxide ion concentration is being reduced as they react to from water molecules
What is a base?
Compounds which neutralise acids to produce water
What is a salt?
A salt is a compound formed when the metal ion from an alkali replaces the hydrogen ion of an acid
A balanced ionic state equation can be expanded and written from a word equation by following what procedure?
B- write a Balanced equation
I- show the charges on Ionic compounds
S- introduce State symbols (s, aq, g, l)
E- Expand ionic formulae of solutions
What do you calculate the number of moles?
Number of moles = concentration x volume
What do you calculate the mass?
Mass=number of moles x mass of 1mole (gfm)
What are the steps to calculating the mass if you are given the concentration and volume?
Step 1 = number of moles = concentration x volume
Step 2 = mass = number of moles x mass of 1 mole (gfm)
How do you calculate the concentration if you are given the volume and mass?
Step 1 = Number of moles = mass divided by mass of 1 mole (gfm)
Step 2 = concentration = number of moles divided by volume
What steps do you use to calculate the concentration of an acid using volume and concentration
Step 1= write a balanced equation
Step 2= calculate the number of moles of the standard solution
Step 3= use the mole relationship to the calculate the number of moles of the unknown
Step 4= calculate the concentration of the unknown using the equation concentration=number of moles divided by volume
