2708739
Descrição
FlashCards por kristy baker, atualizado more than 1 year ago
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Criado por kristy baker
mais de 9 anos atrás
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| Questão | Responda |
| ionic bonding happens between a ... | metal and a non-metal. |
| in ionic bonding the metal becomes ______ charged ion? | in ionic bonding the metal becomes a positively charged ion. |
| in ionic bonding the non-metal becomes a ______ charged ion. | in ionic bonding the non-metal becomes a negatively charged ion. |
| how do oppositely charged ions arrange them selves in a giant ionic lattice? | in a regular way. |
| 2 properties of ionic compounds? | high melting point high boiling point because a lot of energy is needed to break the strong bonds. |
| can ionic compounds conduct electricity when soild? | no ionic compounds only CONDUCT electricity when dissolved in water or are melted. |
| why do ionic compounds conduct electricity when they're liquids? | when liquid they lave free or delocalised electrons that move around. |
| what type of elements does covalent bonding take place between? | non-metals. |
| are ions formed during a covalent bond?ni | no, as no electrons are gained or donated. |
| what two methods are used to display atomic structure? | -dot and cross diagram: Electron shells are drawn as circles, with the electrons on each shown as dots or crosses -the written numbers.example, lithium is 2.1, neon is 2.8.8, and calcium is 2.8.8.2. |
| give three examples of simple molecules with covalent bonds. | hydrogen, ammonia, methane and water .etc |
| simple molecules with covalent bonds have very ____A___ bonds between the atoms but much _____B_____forces holding the molecules together. | A)strong B) weaker |
| when you boil/melt water what breaks for it to change form? | it is it weak intermoleculer forces that break not the strong covalent bonds. |
| what type of boiling and melting points do simple molecular substances have. | low boiling low melting |
| what state are most simple covalent molecules in at room temperature. | gases at room temperature. |
| two features of a giant covalent structure? | very high melting point- e.g.graphite's is 3600 degrees celcuis. variable conductivity-graphite conducts but diamond does not. |
| describe graphite structure. | - Graphite contains layers of carbon atoms. -each carbon atom has 3 bonds leaving one to move around 'freely'. |
| Two uses of graphite? | 1)to write with in pencils. 2) as a lubricant eg. bike chains. |
| how strong are the forces between the layers of carbon in graphite? | they are very weak allowing each layer to slide over each over. |
| what element is carbon made up of? | carbon. |
| why does diamonds structure mean it is very hard and strong? | each carbon atom has a full outer shell and is bonded four times instead of graphite's three bonds. |
| does diamond conduct electricity? | no as unlike graphite it does not have any delocalised electrons. |
| what is metallic bonding? | metallic bonding is when two metal elements bond together. |
| what does crystalline refer to? | solid metals are crystalline- the particles are close together and in a regular arrangement. |
| what does this image show? | this image shows that structure of metallic bonding . metals have loose electrons in the outer shells which form a 'sea' of delocalised negative charge around the close-packed positive ions. There are strong electrostatic forces holding the particles together. |
| what do we need to know about delocalised electrons? | - they are not associated with any particular atom. - they move freely - they are what carries electric or heat energy through the metal. |
| what do the free electrons allow metal atoms to do? | slide over each other which is what makes metal malleable and ductile. |
| define malleable? | a metal that is able to be hammered or pressed into shape without breaking or cracking. |
| define ductile? | a metal that is able to be deformed without losing toughness; pliable, not brittle. (flexible) |
| what would be different between two different isotopes of carbon? | the only difference between two isotope of the same element is the number of neutrons. |
| what is the relative mass of a proton, neutron and electron? | proton 1 neutron 1 electron 0 |
| how is the atomic mass of an isotope found as they all have different amounts of neutrons? | it is found by taking a weighted mean average of all the isotopes weights. |
| where is relative atomic mass (Ar) found? | on the periodic table. |
| where is relative formula mass (Mr) found? | is found by adding up all the Ar's of each atom in the compound. |
| what does the empirical formula tell us? | it tells us the simplest ratio of atoms in a compound. |
| what is one mole of a substance? | One mole of a substance is its gram formula mass (GFM). One mole of a substance contains 6.02 x 1023 formula units. This number is known as the Avogadro constant. |
| what two things do you need to find the percentage of an element? | -relative atomic mass -relative formula mass |
| define theoretical yield? | is the max theoretical mass of product in a reaction. |
| define the actual yield? | is the mass of the product when you actually do the reaction. |
| define the percentage yield? | is the ratio of actual mass of products obtained, compared with the max theoretical mass. |
| whats the equation used to find the percentage yield? | percentage yield= (actual mass of product)/(theoretical mass of product)x 100 |
| what do we use paper chromatography for? | Chromatography can be used to separate mixtures of coloured compounds. |
| explain the process of doing and setting up a paper chromatography experiment? | . A spot of the mixture is placed near the bottom of a piece of chromatography paper and the paper is then placed upright in a solvent. As the solvent soaks up the paper, it carries the mixtures with it. Different components of the mixture will move at different rates. This separates the mixture out. |
| what would a suitable solvent for paper chromatography be? | water. |
| what is an RF value? | Different chromatograms and the separated components of the mixtures can be identified by calculating the Rf value |
| how do you calculate the RF value? | Rf = distance moved by the compound ÷ distance moved by the solvent |
| what is retention time? | it is the time taken to pass through a coloumn. |
| when does a chemical reaction take place? | chemical reactions happen when reactant particles collide with enough energy. |
| define an activation energy? | the energy needed for a reaction to take place. |
| what is a reaction time? | time for the reaction to finish. |
| what is the rate of reaction's equation? | rate of reaction=amount of product formed/time taken. |
| what are three factors that may affect the rate of reaction? | -temperture -concentration/pressure -surface area -catalyst -PH level |
| why might temperature affect the rate of reaction? | energy is transferred to the particles so they move faster, they are more likely to collide with enough energy to react. |
| why might concentration/pressure affect the rate of reaction? | increasing this means that there are more particles in the same volume, making them more likely to collide. |
| why might surface area affect the rate of reaction? | the smaller the SA the less collisions where as a larger SA means more collisions. |
| what is a catalyst? | is a substance which increases the rate of reaction without being changed or used up. |
| one benefit of a catalyst? | it can be used over and over again for a long time. |
| does one catalyst work for every reaction? | no, you have to find the right catalyst for the reaction to work. |
| how does a catalyst work? | a catalyst gives the particles a surface to stick to so that they bump into each other more often. Overal number of collisions is not changed but the number of successful ones increases. |
| what is an exothermic reaction? | a reactions where its products have less energy than its reactants.( gives out energy during the reaction) |
| what is an endothermic reaction? | it is a reaction that has products with more energy than its reactants. (takes in energy during reaction). |
| in an endothermic reaction what happens to the surroundings? | their temp decreases. |
| in an exothermic reaction what happens to the surroundings? | the temperature increases. |
| in a reversible reaction if the forward reaction is exothermic then what is the backward reaction? | endothermic. |
| what does this sign mean? | that the reaction is reversible. |
| what process is shown in the flow chart? | the Haber process. |
| the haber process is used to make ammonia, what two elements does it require? | nitrogen and hydrogen. |
| what can ammonia be used for? | fertilizer cleaning fluids floor washes |
| the highest yield is gotten by using low temp and high pressure. why aren't these conditions used industrially? | it can be dangerous as well as very expensive. |
| what does the equation look like for making ammonia? | nitrogen+hydrogen=ammonia |
| what is neutralisation? | when an acid reacts with a base to make salt and water. |
| what does an acid+base =? | salt+water |
| what does an acid+metal oxide=? | salt+water |
| what does an acid+metal hydroxide=? | salt+water |
| what do most bases not do? | most bases do not dissolve in water. |
| bases that dissolve in water are called something else. what is it? | an alkali. |
| what happens when an acid and a carbonate react? | acid+metal carbonate=salt+water+carbon dioxide |
| when carbon dioxide is produced in a acid+carbonate reaction, what can be seen? how do you make sure that its carbon dioxide? | 1)it causes bubbling during the reaction. 2) pass it through lime water if it turns cloudy carbon dioxide is present. |
| two reactive metals that acid will react with? | magnesium zinc |
| when an acid reacts with a reactive metal what is produced? | salt and hydrogen. acid+metal=salt+hydrogen |
| what does hydrogen do during an acidic reaction? how do you test for hydrogen? | 1) it will cause fizzing. 2) you light a splint and place it in a container of the unknown gas, if it makes a pop sound then it is hydrogen. |
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