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31 Cards in this Set
- Front
- Back
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Name two chemicals that you might come across in everyday life.
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Food additives, cleaning products, drugs, fertilisers.
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Give an example of one chemical that is produced on a small scale and one that is produced on a large scale.
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Small scale: Pharmaceuticals. Large scale: Sulfuric acid
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Which pH range is acidic?
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1 to 6
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Which pH range is alkaline?
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8 to 12
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Name two ways in which you can measure the pH of a substance.
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Universal indicator, pH meter or litmus paper.
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What is an acid?
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A substance with a pH of less than 7 which produce aqueous hydrogen ions (H+) in water.
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What is an alkali?
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A substance with a pH of greater than 7 which produce aqueous hydroxide ions (OH-) in water.
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What types of ions are always present in an acid?
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H+
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What types of ions are always present in an alkali dissolved in water?
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OH-
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Write the ionic equation for neutralisation.
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H+ + OH- → H2O
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Write the balanced symbol equation for when you add hydrochloric acid to zinc.
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2HCl + Zn → ZnCl2 + H2
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Write a balanced symbol equation for when you add sulfuric acid to magnesium.
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H2SO4 + Mg → MgSO4 + H2
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Write the equation for when you add hydrochloric acid to copper oxide.
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2HCl + CuO → CuCl2 + H2O
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Write the equation for when you add hydrochloric acid and calcium hydroxide.
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2HCl + Ca(OH)2 → CaCl2 + 2H2O
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When designing a chemical process what is involved in carrying out a risk assessment?
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Identifying the hazards, assessing who may be harmed, how to reduce the risk.
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Why is it important to choose the right apparatus for a chemical process?
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To ensure it is the correct size and strength.
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What does calculating the yield tell you about the reaction?
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Overall success of the process
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How would you separate an insoluble product from a liquid reaction mixture?
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Filtration
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Name two stages in the synthesis of a chemical where evaporation can be useful.
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Evaporation and drying
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Give two methods used to dry a product
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Drying oven and using a desiccator
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What is the formula for percentage yield?
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(Actual yield/theoretical yield) x 100
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Describe how to carry out a titration
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Add a known volume of alkali to the titration flask with a few drops of indicator. Fill a burette with the acid. Using the burette, add the acid slowly to the alkali whilst swirling the conical flask to ensure the two chemicals mix completely. Add the acid drop-wise when you are near the end point which is indicated by a colour change. This is when the alkali has been neutralised. Record the volume of the acid used to neutralise the alkali.
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Why is purification of a product important?
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To ensure the product is free from impurities or contaminants.
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What term is used to describe a reaction where energy is taken in?
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Endothermic
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What term is used to describe a reaction where energy is given out?
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Exothermic
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In an exothermic reaction, which has more energy, the reactant or the products?
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Reactants
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When drawing an energy level diagram, what are the two axes labelled as?
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x is progress of reaction, y is energy
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Why is it important to control the rate of a chemical reaction in industry?
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To ensure the temperature of the reaction does not increase so much that the reactants become gases and could potentially explode.
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What four things affect the rate of reaction?
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Temperature, concentration, catalyst, surface area
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Magnesium metal was placed into a solution of 0.1 M hydrochloric acid. The reaction produced 50 cm3 of hydrogen. Would you expect the same reaction with 0.2 M hydrochloric acid to be faster or slower? Why?
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Faster because the concentration of acid has increased so there are more molecules in the same area and there will be more successful collisions.
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Describe three ways of measuring the rate of a reaction.
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1: Precipitation and colour change, 2: Change in mass (using a balance), 3: The volume of gas given off.
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