C4 Chemical Changes Flashcards
<p>What ion do Alkalis form when they dissolve in water?</p>
<p>Alkalis form hydroxide (OH-) ions when they dissolve in water</p>
<p>What ions do Acids form when they dissolve in Water?</p>
<p>Acids form hydrogen (H+) ions when they dissolve in water</p>
<p>How do Acids and Alkali neutralise each other?</p>
<ul><li>Acids form hydrogen (H+) ions when they dissolve in water</li><li>Alkalis form hydroxide (OH-) ions when they dissolve in water</li><li>When an acid and alkali mix, the H+ of the acid and OH- ions of the alkali combine to form H2O, otherwise known as water</li><li>Water is a neutral substance so an acid and an alkali neutralise each other</li></ul>
<p>What is <b>Oxidation</b>?</p>
<p>Oxidation a reaction involving the gain of oxygen. Oxidation is also the loss of electrons</p>
<p>What is <b>Reduction</b>?</p>
<p>Reduction is a reaction involving the loss of oxygen. It is also the gain of electrons</p>
<p>What are <b>Redox</b> Reactions?</p>
<p>Redox reactions is when one substance undergoes reduction and the other substance undergoes oxidation</p>
<p>What is the reactivity Series?</p>
<p>The reactivity series is a list of element planced in order of reactivity</p>
<p>List the reactivity series in order from most reactive to least reactive</p>
<ul><li>Potassium (Most Reactive)</li><li>Sodium</li><li>Lithium</li><li>Calcium</li><li>Magnesium</li><li>(Carbon)</li><li>Zinc</li><li>Iron</li><li>(Hydrogen)</li><li>Copper (Least Reactive)</li></ul>
<p>What are <b>displacement reactions?</b></p>
<p>A displacement reaction more reactive metal (one that forms positive ions more easily) can replaces a less reactive metal from a compound</p>
<p>When can a displacement reaction take place?</p>
<p>A metal can only displace another metal from a compound if it is located above it in the reactivity series</p>
<p>What are spectator ions?</p>
<p>Spectator ions are the ions in a displacement reaction that reamin unchanged in the reaction</p>
<p>What are the highly unreactive metals that are found in the Earth's crust called?</p>
<p>Native Metals</p>
<p>What are group 1 elements called Alkali Metals?</p>
<p>When group 1 metals react with water, the solution is Alkaline</p>
<p>What is produced when reactive metals react with water?</p>
<ul><li>Metal Hydroxide</li><li>Hydrogen Gas</li></ul>
<p>What is produced when metals react with dilute acids?</p>
<ul><li>A Salt</li><li>Hydrogen Gas</li></ul>
<p>Why is carbon used to extract metals?</p>
<p>Reducing a metal with carbon will result in the extraction of the metal if the metal is lower in the reactivity series than carbon.
Carbon is used because it is cheap and abundant</p>
<p>How is carbon used to extract metals?</p>
<p>In the reduction, the metal oxide loses oxygen to form a pure metal
Reduction with carbon normally involves heating the metal oxide in the presence of the carbon, which is often used in the form of coal</p>
<p>Which metals react with dilute acids but not cold water?</p>
<ul><li>Magnesium</li><li>Aluminium</li><li>Zinc</li><li>Iron</li><li>Lead</li></ul>
<p>What happens when an acid reacts with a metal carbonate?</p>
<p>Acid + Metal Carbonate → Salt + Water + Carbon Dioxide</p>
<p>What happens when an acid reacts with a metal oxide?</p>
<p>Acid + Metal oxide → Salt + Water</p>
<p>What happens when an acid reacts with a metal?</p>
<p>Acid + Metal → Salt + Hydrogen</p>
<p>What happens when an acid reacts with a metal hydroxide?</p>
<p>Acid + Metal hydroxide → Salt + Water</p>
<p>What is the method to produce a pure, dry sample of a soluble salt from an insoluble oxide or carbonate?</p>
<ul><li>Gently warm an acid using a bunsen burener and continually add the insoluable solid, whilst stirring, till no more reacts</li><li>Filter the solution to remove any excess insoluble solid</li><li>Heat the solution in an evaporating basin above a beaker of water - the beaker of water ensures a gentle heating</li><li>Leave the solution to cool - As the water evaporates, the solution becomes concentrated which allows the salt to crystalise</li></ul>
<p>What are two ways to measure pH?</p>
<ul><li>Universal Indicator</li><li>pH Probe</li></ul>
<p>What does the pH of an chemical tell you?</p>
<p>The pH tells you the concentration of H+ ions in a solution</p>
<p>What happens to the concentration of H+ ions every time the pH increases by 1?</p>
<p>As the pH increases by 1, the concentration of H+ divides by 10</p>
<p>What is the concentration of H+ ions at pH 0?</p>
<p>1 mol/dm3</p>
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