C5 Chemical Changes Flashcards
Is carbon more or less reactive than iron?
More reactive
A substance does not corrode in air or water. What word could describe this substance?
Non-corrosive
Magnesium sulphate can be made by reacting magnesium metal with an acid. A gas is also produced. Name this gas.
Hydrogen Gas
What is an ion?
The charged particle formed when an atom gains or loses electrons
What is a displacement reaction?
When a more reactive substance takes the place of a less reactive substance
What is an alkali?
A soluble base
What is reduction?
The loss of oxygen OR the gain of electrons
What are bases?
Ionic compounds that can neutralise acids
What is oxidation?
The gaining of oxygen OR the loss of electrons (OIL)
Metal + Oxygen =
Metal oxide
Metal + Water =
Metal hydroxide + hydrogen
Metal + acid =
Metal salt + hydrogen
Acid + base =
Salt + water
Acid + Alkali =
Salt + water
Acid + carbonate =
Salt + water + carbon dioxide
What is the charge of a group 1 metal?
+1
What is the charge of Ammonium?
+1
What is the charge of a group 2 metal?
+2
What are the charges of Group 7 metals?
-1
What is the charge of Aluminium?
+3
What are the charges of Group 7 metals?
-1
What is the charge of a Nitrate?
-1
What is the charge of a Hydroxide?
-1
What is the charge of a Sulphate?
-2
What is the charge of a Carbonate?
-2
What is the charge of an oxide?
-2
What salt does hydrochloric acid form?
Chlorides
What salts do Sulphuric acids form?
Sulphates
What salts do Nitric acids form?
Nitrates
Order the following fastest to slowest reactions - iron rusting, spaghetti cooking, rifles firing, rocks weathering, milk going sour, fireworks burning
Rifles firing, fireworks burning, spaghetti cooking, milk going sour, iron rusting, rocks weathering
What happens in a chemical reaction?
Substances react to make something new, indicated by chemical and physical changes
What are the signs of a chemical reaction?
Colour change, pop sound, fizzing
How do you calculate rate of reaction?
Rate = Quantity of product / Time
What is a catalyst?
A substance that increases the rate of reaction without itself undergoing any permanent chemical change
Why does reaction slow down on an annotated rate graph?
Less collisions, no more reactants - product formed
Give the 4 ways to speed up a reaction:
- Increasing temperature
- Increasing the concentration
- Increasing the pressure
- Increasing the SA:V ratio
What is collision theory?
In order for a reaction to take place reactant particles must collide with sufficient energy
The more collisions per second the ———- the rate of reaction
Faster
What is an ion?
The charged particle formed by the loss or gain of electrons
What is a displacement reaction?
When a more reactive substance takes the place of a less reactive substance
What is oxidation (REDOX)?
The gaining of oxygen or the loss of electrons
What is reduction (REDOX)?
The loss of oxygen or the gain of electrons
What is a base?
Ionic compounds that can neutralise acids
What is an alkali?
A soluble base
Metal + oxygen —>
Metal oxide
Metal + water —>
Metal hydroxide + hydrogen
Metal + acid —>
Metal salt + hydrogen
Acid + base —>
Salt + water
Acid + alkali —>
Salt + water
Acid + carbonate —>
Salt + water + carbon dioxide
What is the charge of group 1 metals?
+1
What is the charge of a nitrate ion?
-1
What is the charge of a hydroxide ion?
-1
What is the charge of a sulphate ion?
-2
What is the charge of an oxide ion?
-2
What is the charge of a carbonate ion?
-2
What is the charge of group 7 elements?
-1
What do more reactive metals occur as?
Ores
What does Hydrochloric acid (HCl) form?
Chlorides (Cl-)
What does Sulphuric acid (H2SO4-2) form?
Sulphates (SO4-2)
What does Nitric acid (NO3-) form?
Nitrates (NO3-)
What is the state symbol for a solid?
s
What is the state symbol for a liquid?
l
What is the state symbol for a gas?
g
What is the state symbol for aqueous?
aq
What are the 3 steps to follow when forming ionic and half equations?
- Write a balanced symbol equation - with states
- Separate the ions into single elements and add the charges
- Delete the species that appear exactly the same on both sides (should now be 2 charged elements per side)
FOR HALF EQUATIONS ONLY: Balance charges of the 2 elements on either side by expressing the number of electrons which would need to be added to form a neutrally charged atom
What does reactivity depend on?
Tendency to form metal ions
What does OILRIG stand for?
Oxidation is Loss of electrons
Reduction is Gain of electrons
Metal + Oxygen —>
Metal Oxide
Metal + Water —>
Metal Hydroxide + Hydrogen
Metal + Acid —>
Metal Salt + Hydrogen
What is the equation for neutralisation?
H+ + OH- –> H20
What is the neutral pH?
7
Are hydrogen ions positive or negative?
Always positive
Are hydroxide ions positive or negative?
Always negative
How do strong acids ionise?
Strong acid completely ionises in water - all molecules split up into ions and stay split up so it breaks down fully into its ions. Remember hydrogen ions are always positive
How do weak acids ionise?
Weak acids only partially ionise in water. Only 2 of the acid molecules usually split apart. The number of H+ ions is much less, so the pH of the acid will be higher
What is the function of cyolite?
Reduces the melting point
Which electrode is positive?
Anode
Which electrode is negative?
Cathode
Which electrode attracts positive metal ions?
Cathode (Cations)
Which electrode attracts negative metal ions?
Anode (Anions)
What are the top 3 most reactive metals?
Potassium, Sodium, Calcium
What are the only 4 elements less reactive than Hydrogen?
Copper, Silver, Gold, Platinum
What is a displacement reaction?
When a more reactive metal is reacted with a compound containing a less reactive metal it will replace that metal in the compound
What are the 4 signs of chemical change for displacement reactions?
Bubbles, temperature change, precipitate (solid forming), colour change
When are metals more reactive?
If they lose outer shell electrons more easily
What are examples of neutral (pH 7) substances?
Pure water
What are examples of basic/alkaline (pH 8-14) substances?
Bleach, soap, baking soda
What are examples of acidic (pH 0-6) substances?
Lemon, stomach acid, milk
What happens when acidic substances dissolve in water?
When acidic substances dissolve in water they dissociate - the acid breaks apart to release hydrogen (H+) ions (ionising)
What type of substance has an excess of H+ ions?
Acid
What type of substance has an excess of OH- ions?
Alkaline/base
What is concentration?
How much acid there is per unit of volume
What is strength (of an acid)?
How much an acid dissociates
Metal + water –>
Metal hydroxide
Metal + oxygen –>
Metal oxide
Metal + acid –>
Salt + hydrogen
Metal oxide + acid –>
Salt + water
Metal hydroxide + acid –>
Salt + water
Metal carbonate + acid –>
Salt + water + carbon dioxide
Ammonia + acid –>
Ammonium Salt
What is a base?
A substance which neutralises an acid