Chemistry unit 1 wjec


  • Created by: Meg Price
  • Created on: 24-01-12 21:15

what are atoms? - the smallest part of any substance

what are elements? - a pure substance that cant be split

what are compounds?- 2 or more elements chemically combined

what is the mass number? -the number of protons and neutrons

what is the atomic number? - the number of protons (equal to electrons)

what is the structure of an atom? a nucleus containg protons and neutrons, with energy levels (or shells) surrounding them

what are the maximum umber of electrons in the first and second shell ? 2 and 8

what is the overall charge of atoms and why? neutral because protons are positive, electrons are negative, and neutrons are neutral

carbon is atomic number 6- how many electrons in the first and outer shell? 2 and 4

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how do you balance equations? -write the formula for each substance, check for an unbalanced element, and ensure they are the same on each side, repeat this for every other element.

give some properties of metals:- duchile, malleable, magnetic, conducts heat, strong,and high melting points

give some properties of non metals:- dull, low denstiy, brittle, poor conductors.

whats the common name for group 7 elements?- halogens

how many electrons do they have in their outer shell? - 7

which area of them are more reactive? - the top elements are the most reactive

what happens to the melting and boiling points as you go down the group?- they increase

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what are group one metals aka? - alkali metals

how many electrons do they have in their outer shell? - 1

what happens to the reactivity as you go down the group? - they increase

give some properties of group one metals:- low melting points and densitys

why do group one and seven elements react well? because group one elements want to loose an electron and group seven elements want to gain an electron so they both become a noble gas and so they have a stable structure

what does a flame test distinguish? - what metal is present becasue each metal has a diferent colour

what colour does lithium go ? red

what colour does sodium go? yellow/orange

what colour does potassium go ? lilac

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what does the silver nitrate test identify? -the non metals present in the compound as each one has a different colour

what colour does chlorine go?-white

bromine? -green

iodine?- yellow

what is the equation for group one metals and oxygen? - group one metal + oxygen --> group one metal oxide

what is the ratio for balancing this equation?- 4.2.1

what is the equation for group one metals and water? - group one metal + water --> group one metal hydroxide + hydrogen

what is the ratio for balancing this equation? 2.2.2.H2

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what is the equation for group one and seven metals? - group 1 + group 2 --> compound

what is the ratio for balancing this equation? - 2.1.2

what is the equation for metal halide and a reactive halogen?  metal halide + more reactive halogen --> metal halide + less reactive halogen

what is the ratio for balancing this equation? -

what is the canel and swap rule? when you find the valency for the two elements, if they can, canel them down, swop them over and then you have your compund.

what are the four reactions fo acids? 1.) metal carbonate + acid --> salt + water + co2 2.) metal +acid --> salt and water       3.) metal oxide + acid --> salt and water                4.) metal hydroxide + adic --> salt + water

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what is rate of reaction ? how quickly do the products form in a chemical reaction

what are the four things that effect rate of reaction? temperature, surface area, catalysts and concentration

explain temperature: rate of reaction increases as the particles have more energy so there is an increased change of collisions

explain surface area: the rate of reaction increases with the increase of surface area because the reactants of a solid can only take place at the solid surface, so a larger area means there is extra surface for molecules to colllide with

explain concentration: rate of reaction increases with the increase of concentration becasue there are more particles of the reactant to collide with

explain catalysts: speed up reactions, give particles a surface to stick to, they reduce costs in industrial reactions, and they have to be physically removed after reaction as they dont get used uo

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what are catalysts? substances that speed up reactions but they do not get used up in the reactions

what are some examples? gauzes, pellets or powders

what is crude oil? a mixtrue of hydrocarbons that is seperated by fractional distilation to form useful products

how was crude oil formed? it is found in sedimentaryrocks, millions of years ago when animals and plants died they dropped to the bottom of the sea and their remains where covered by mud, the mud was covered by more sediment and the plants and animals slowly turned into crude oil.

what is fractional distillation? it seperates a mixture into a number of different parts called fractions.

how does it do this? a tall coloumn with different condensers coming off it heats up the mixture and becasue all the different fractions have different boiling points the all come off at different sections, which seperates them.

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What is LPG? it is used in bottles cooking gas and contains propane and butane

what is petrol (gasoline)? - its used as fuels for cars

what is napatha? - used in the chemical industry

what is paraffin? - its used for aircraft fuels

what is heating oil? - its used for heating and diesel

what is fuel oils? - used for ships and power stations

what is bitumen?- used for surfaces of roads and roofs

which one makes better fuels: hydrocarbons with small molecules or hydrocarbons with large molecules? - small molecules becasue they are volatile and they flow easily

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what is combustion? a chemical reaction which involves a fuel burning

what is the general formula? FUEL + OXYGEN --> CO2 + WATER

what is the combustion in cells called? respiration

what are endothermic reactions? changes to chemical bonds, existing bonds are broken, it takes in heat so delta H is positive

what are exothermic reactions? changes to chemical bonds, produces new bonds, it lets heat out so delta H is negative

how do you calculate Delta H? add up the number of bonds (e.g C-C) times them by their value which will be provided, so the same for products, reactants- products, state if delta H is positive or negative

what is acid rain caused by? sulphur dioxide and nitrogen oxides, caused by internal combustion such as power stations and car engines

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what does acid rain cause? - it causes lakes to beome acidic, so it harms plants and animals, it corrodes things and damages limestone.

what are the main features in the carbon cycle? respiration, photosynthesis, decay, combustion and feeding.

what is the evolution of the earths life atmosphere? the earth was formed, cooled and formed the crust, water vapour condensed caused oceans, plant life, organism development, ozone layer, increase in oxygen, more complex organisms

what have CO2 levels decreased? because there is more vegetation photosynthesising and it is dissolving in oceans.

why do we have global warming? because the sun rays come down to earth, and then bounce back into space, green house gases stop them bouncing back into space so the rays get trapped around the earth which heats the earth up. CO2 is increasing as the population is increasing, and less plants due to land used for building and living space

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what can we do to stop global warming? use our car less by using public transport or waling, reduce, reuse and recycle, cut down on aerosols

what happens if global warming isnt stopped? increase in floods and droughts, starvation, glaciers melting, animal extinction e,g polar bears, sea level is rising.

what are the thee types of rocks? igneous, metamorphic and sedimentary

what is igneous rock? formed by magma when it cools inside the earth

what is an example of igneous rock? balsalt and granite

what is metamorphic rock? rocks that have been subjected to heat or pressure that have changed them into different rocks

what are examples of metamorphic rock? marble( from limestone) , slate (from clay)

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what is sedimetary rock? they are formed from sediments that have settled and the bottom of a lake sea or ocean, that have been compressed, they are layer forms and they come from erroded rocks

what are examples of sedimentary rocks? sandstone, limestone, chalk and clay

what are the main features of the rock cycle in order? it rains, igenous gets weathered into the sea, forms sedimentary-metamorphic, rock melted, magma rises, forms intrusive igneous, and then extrusive igneous

whats the formation of the earth, from the outside to the inside? crust, mantle, outer core, inner core.

what are the four theoried of the formation of the earths crust? - creationism, contracting earth, isostatic uplift, explanding earth

what is creationism? that the earth and all living things where created by God

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what is contracting earth? the earth started as a large hot ball of matter, then cooled and contracted causing geological features

what is isostatic uplift? much of N europe was covered by ice sheets which melted and caused the crust to sink into the fluid mantle, the removal of mass from the crust made it float

what is explanding earth? the earth started as a small planet with no ocean and it expanded, broke up the crust and formed cracks

what are plate tectonics? the crust is made of about 12 plates, these float on the mantle, convection currents cause the plates to move about 2cm a year which have a great effect over a long period of time.

what is the continental drift? scientists think the plates where origianlly one continent called PANGEA, over millions of years they have drifted to their present positions

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what is evidence to support plate techtonics? the continents fit together like a jigsaw, the similarities is rock layers, the similarities in fossils, the evidence of related species

what are effects that can occur at plate boundaries? - plates can judder past each other, volcanoes, collisions, earth quakes, subduction

what is subduction? when the oceanic plate is forced under the continental plate

what is nanoscience? the study and development on nanoscales

what are some uses- self cleaning titanium oxide glass and nano silver in socks to reduce odour

what are the possible dangers? we dont know long term effects and they are so small they could be absorbed into the body.

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