Category A
What is the law of conservation of mass
Mass cannot be created or destroyed, only rearranged.
The same number and type of atoms in the reactants are in the products
What is pH 7? provide an example
The pH a solution moves towards during neutralisation.
Water (H2O)
The word equation for a neutralisation reaction.
Acid + Base → Metal Salt + Water?
This gas is produced when acid reacts with carbonate.
This is Carbon Dioxide (CO2)
This solution is used to test for carbon dioxide.
Limewater (Calcium Hydroxide)
Why would mass appear not to be conserved in a Neutralisation reaction
The gas has escaped
Write the net ionic equation showing how water forms.
H⁺ + OH⁻ → H₂O
What is the acid found in vinegar.
Ethanoic Acid
In class, Tom combined 40g of baking soda with 110g of vinegar in a sealed container. After watching the reaction, how can Tom know the mass of the products without measuring them?
He can add the mass of the reactants:
40g + 110g = 150g
What type of ions do bases contain
OH (hydroxide ions) OR CO (Carbonate ions)
Found on the left hand side of the equation
Reactant
Why does the pH increase when NaOH is added to an acid?
OH⁻ ions remove H⁺ ions, reducing acidity.
How do you identify an acid from a base?
WHAT observation would you see when you test a strong acid from a weak acid AND when you test a strong base from weak base. What colour would a neutral substance turn.
Use universal indicator, UI will turn red if an acid is strong, a weak acid will turn yellow. A strong base will go purple and a weak base will go blue. Neutral substance (H2O) will turn green.
What is the difference between an open system and a closed system?
A closed system is all contained and no mass can escape, whereas a open system means that things such as gas can escape into the atmosphere
Acids contain this type of ion
H+ (hydrogen)
The right hand side of the arrow
product
A student reacts sulfuric acid with sodium hydroxide.
Name the salt formed.
Sodium sulfate
The observation when carbon dioxide is bubbled through limewater.
Limewater turns cloudy/milky
Describe what happens to the atoms in a chemical reaction.
The atoms get rearranged to form one or more new substances.
How does water form in neutralisation
The H+ ions from the acid combines with OH ions to produce H+OH ->H2O
What is wrong with this chemical equation?
2H2 + O2 --> 3H2O
Its not balanced
there are more H on the products (6) as well as oxygen (3)
reactants 4 hydrogen and 2 oxygen
Why would you add excess metal oxide to an acid during the reaction
To ensure all the acid reacts and is completely neutralised.
Explain how you would isolate the salt from Hydrochloric acid reacting with copper oxide. AND What is the salt that forms at the end?
The solution is filtered and evaporated. This metal salt is formed. copper chloride
Put these steps in order:
A. Evaporate water
B. Add excess metal oxide
C. Filter excess solid
D. Heat acid
D → B → C → A
What ions form the salt in neutralisation
HCl + NaOH -> NaCl + H2O
the negative from the acid and the positive from the base
Na - from the base (positive ion)
Cl - from the acid (negative ion)