Chemical Changes Flashcards
Describe how metals react with oxygen and state the compound they form, define oxidation and reduction
Metal + oxygen = metal oxide
Oxidation - addition of oxygen (loss of electron)
Reduction - removal of oxygen (gain of electrons)
Describe the arrangement of metals in the reactivity series, including carbon and hydrogen, and use the reactivity series to predict the outcome of displacement reactions
Potassium
Sodium
Lithium
Calcium
Magnesium
Carbon
Zinc
Iron
Hydrogen
Copper
Recall and describe the reactions, if any, of potassium with water or dilute acids
Potassium + dilute acid = explosive reaction
Potassium + water = a reaction
Recall and describe the reactions, if any, of sodium with water or dilute acids
Sodium + dilute acid = explosive reaction
Sodium + water = reaction
Recall and describe the reactions, if any, of lithium with water or dilute acids
Lithium + dilute acid = explosive reaction
Lithium + water = reaction
Recall and describe the reactions, if any, of calcium with water or dilute acids
Calcium + dilute acid = explosive reaction
Calcium + water = reaction
Recall and describe the reactions, if any, of magnesium with water or dilute acids
Magnesium + dilute acid = moderate reaction
Magnesium + water = no reaction
Recall and describe the reactions, if any, of zinc with water or dilute acids
Zinc + dilute acid = moderate reaction
Zinc + water = no reaction
Recall and describe the reactions, if any, of iron with water or dilute acids
Iron + dilute acid = moderate reaction
Iron + water = no reaction
Recall and describe the reactions, if any, of copper with water or dilute acids
Copper + dilute acid = no reaction
Copper + water = no reaction
Relate the reactivity of metals to its tendency to form positive ions and be able to deduce an order of reactivity of metals based on experimental results
The more reactive metals form positive ions more easily, this also means they react with water and acid easily
Recall what native metals are and explain how metals can be extracted from the compounds in which they are found in nature by reduction with carbon
Native metals - a pure metal in its metallic form in nature
Potassium, sodium, lithium, calcium and magnesium can be extracted from compounds using electrolysis.
Zinc, iron and copper can be extracted from their oxides using carbon.
HT ONLY: Describe oxidation and reduction in terms of loss and gain of electrons
Oxidation - loss of electrons
Reduction - gain of electrons
HT ONLY: Write ionic equations for displacement reactions, and identify which species are oxidised and reduced from a symbol or half equation
Mg(s) + Zn2+(aq) = Mg2+(aq) + Zn(s)
Oxidation - Mg = Mg2+ + 2e-
Reduction - Zn2+ + 2e- = Zn
Explain that acids can be neutralised by alkalis, bases and metal carbonates and list the products of each of these reactions
H+ + 0H- = H20
Acid + alkali = water (neutral)
Acid + metal carbonate = salt + water + carbon dioxide
Acid + metal oxide = salt + water
Acid + metal hydroxide = salt + water
Predict the salt produced in a neutralisation reaction based on the acid used and the positive ions in the base, alkali or carbonate and use the formulae of common ions to deduce the formulae of the salt
HCl - chloride
H2SO4 - sulfate
HNO3 - nitrate
Describe how soluble salts can be made from acids and how pure, dry samples of salts can be obtained
Soluble salts are made from adding metals and insoluble metal compounds to acids. The excess solid is filtered and remaining salt solution if crystallised.
Recall what the pH scale measures and describe the scale used to identify acidic, neutral or alkaline solutions
The pH scale measures what pH the substance is in terms of how acidic or alkaline it is or if it’s neutral.
Define the terms acid and alkali in terms of production of hydrogen ions or hydroxide ions (in solution), define the term base
Acid - pH less than 7, produces H+ ions in water
Alkali - pH more than 7. produces OH- ions in water
Base - a substance with a pH higher than 7
Describe the use of universal indicator to measure the approximate pH of a solution and use the pH scale to identify acidic or alkaline solutions
The universal indicator changes colour depending on the pH - it gives an approximate value. You can use the pH scale to use the colour the universal indicator provides to identify the exact pH.
HT ONLY: Use and explain the terms dilute and concentrated (in terms of amount of substance) and weak and strong (in terms of the degree of ionisation) in relation to acids
Dilute - low concentration (low amount of particles)
Concentrate - high concentartion (high number of particles)
Weak acid - partially ionises in water to produce hydrogen ions.
Strong acid - completely ionises in water to produce hydrogen ions
HT ONLY: Explain how the concentration of an aqueous solution and the strength of an acid affects the pH of the solution and how pH is related to the hydrogen ion concentration of a solution
The pH will be lower if there is a higher concentration.
Describe how ionic compounds can conduct electricity when dissolved in water and describe these solutions as electrolytes
Ionic compounds can conduct electricity when in electrolytes due to the electrons being free to move and carry charge.
Describe the process of electrolysis
Electrolysis - the process in which a ionic compound is broken down into its elements using a electrical current
Use the reactivity series to explain why some metals are extracted with electrolysis instead of carbon
Some metals are extracted with electrolysis instead of carbon due to being more reactive than carbon.
