chemistry: c2

kristy baker
Flashcards by , created about 4 years ago

This is an overview of the whole of c2, it starts with c2.1 and goes throught to c2.7. C2.1 structure and bonding C2.2 how structure influences properties C2.3 atomic structure and quantitative chemistry C2.4 rates of reaction C2.5 exothermic and endothermic reactions C2.6 acids bases and salts C2.7electrolysis

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kristy baker
Created by kristy baker about 4 years ago
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Question Answer
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? 3a29acae-f3b7-44ce-b07e-669d17a52cd9.jpg (image/jpg) 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. e7585ce4-b06f-42fd-b1e4-1f43ebbc9ff1.jpg (image/jpg)
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? b5a2c4be-aab2-451c-82e4-ae09271781e4.png (image/png) that the reaction is reversible.
what process is shown in the flow chart? a4d92230-9f23-4d7f-a7a0-34d78c18f1c2.gif (image/gif) 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 6cfc5021-d576-473f-998e-ef7e3ebb4aee.png (image/png)
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.