Topic 3a Flashcards
Done except for a few specpoints
3.1
What ion do acids produce an excess of when dissolved in water?
Hydrogen ions
H+
3.1
What ion do alkalis produce an excess of when dissolved in water?
Hydroxide ions
OH-
Define an ion
An atom that has lost or gained electrons
Define a poly-atomic ion
Groups of atoms held by covalent bonds lose/gain electrons
3.1
Explain why the pH of hydrogen bromide becomes acidic when dissolved in water?
H+ ions form making it acidic
3.2
a) A neutral solution has a pH of…?
b) Acidic solutions have a pH of…?
c) Alkali solutions have a pH of…?
a) 7
b)1-6
c) 8-14
What is an advantage to having internationally agreed hazard symbols?
Anyone can understand them and stay safe
What is the main advantage to using a pH probe?
Measurements are accurate
3.4
The most acidic rain recorded in Britain had a pH of 2. How much more acidic is this than normal rainwater with a pH of 5. [2 marks]
10 × 10 × 10 =
×1000 more H+ ions
3.5
Describe the relationship between the pH and the concentration of hydrogen ions
As the pH decreases by 1, the concentration of H+ ions increases by a factor of 10
3.5
Describe the relationship between the pH and the concentration of hydroxide ions
As the pH increases by 1, the concentration of OH- ions increases by a factor of 10
3.7
Explain the term dilute
Contains relatively small v of dissolved solute
3.7
Define the term concentrated
Contains relatively large amount of dissolved solute
3.8
What is a strong acid?
-Completely dissociates to form H+ ions in solution
-High concentration of H+ ions
3.8
What is a weak acid?
-Partially dissociates to form H+ ions in solution
-Low conc H+ ions
3.10
What are alkalis?
-Soluble bases
-pH greater than 7
3.9
What is a base?
Neutralise acids to form salt + water
I find an unmarked bottle and want to work out if the liquid inside is acidic or not. How could I do this?
Universal indicator
If it’s red/orange/yellow it’s an acid
Why are metal oxides bases?
They neutralise acids
3.11
State 4 reaction equations of aqueous solutions of acids that produce salts
Metal + Acid –> Salt + Hydrogen
Metal oxide + Acid –> Salt + Water
Metal hydroxide * + Acid –> Salt + Water
Metal carbonate + Acid –> Salt + Carbon dioxide + Water
Acid + Alkali –> Salt + Water
Typically alkalis *
3.11
What salt will hydrochloric acid form?
Chloride
3.11
Which salt will sulfuric acid form?
Sulfate
3.11
Which salt will nitric acid form?
Nitrate
3.11
Finish the equations:
a) Zinc oxide + Sulfuric acid –>
b) Sodium oxide + Hydrochloric acid—>
Zinc sulfate + Water
Sodium chloride + Water
3.11
What happens to the ions from acids and alkali during a neutralisation reaction?
H+ ion from acid combines with OH- ion from alkali to form water
Name 3 common acids
Hydrochloric acid - HCl
Sulfuric acid - H₂SO₄
Nitric acid - HNO₃
Name 3 common alkalis
Sodium hydroxide - NaOH
Potassium hydroxide - KOH
Calcium hydroxide - Ca(OH)₂
Name 3 polyatomic ions
Hydroxide - OH^-
Carbonate - CO₃²^-
Nitrate - NO₃^-
What is the ionic formula for sodium?
Na(+)