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| Questão | Responda |
| What is an atom's atomic number and mass number? | The atomic number of an atom is its number of protons. |
| What are the relative masses of protons and neutrons? | The relative mass of protons and neutrons is 1. |
| What are isotopes? | Isotopes are atoms of same element with different numbers of neutrons. |
| How can we calculate the relative formula mass of a compound from the elements? | We can work out the relative formula mass of a compound by adding up the relative atomic masses of the elements in it, in the ratio shown by its formula. |
| What do balanced symbol equations tell us about chemical reactions? | Balanced symbol equations tell us the number of moles of substances involved in a chemical reaction. |
| What does the yield of a chemical reaction describe? | The yield of a chemical reaction describes how much product is made. |
| What are the factors affecting the yield of a chemical reaction? | Factors affecting the yield of a chemical reaction include product being left behind in apparatus and difficulty separating the products from the reaction mixture. |
| Why is it important to achieve a high yield in industry and to waste as little energy as possible? | It is important to maximise yield and minimise energy wasted to conserve the Earth's limited resources and reduce pollution. |
| What is a reversible reaction? | The products of the reaction can react to make the original reactants. |
| What are food additives? | Food additives are substances added to food in order to improve its appearance, taste and how long it will keep. |
| How can we identify food additives? | Food additives can be identified by using paper chromatography. |
| Gas chromatography | The process of separating the components in a mixture by passing the vapours through a column and detecting them as they leave the column at different times. |
| Mass spectrometer | A machine that can be used to analyse small amounts of a substance to identify it and to find its relative molecular mass. |
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