module 1 Flashcards

Question

What is evaporation?

Answer 1

Pour solution in to evaporating dish, slowly heat solution. Solvent will evaporate and solution will get more concentrated. Eventually crystals will start to form. Keep heating evaporating dish until all you have left are dry crystals.

Answer 2

Pour solution into evaporating dish and gently heat solution. Some of solvent will evaporate and solution will get more concentrated. Once some of solvent has evaporated or when you see crystals start to form (point of crystallisation), remove dish from heat and leave solution to cool. Salt should start to form crystals as it becomes insoluble in cold, highly concentrated solution, filter crystals out of solution and leave them in warm place to dry. Could also use drying oven or desiccator.

Answer 3

Rock salt is mixture of rock and sand (spread on roads in winter). Salt and sands are both compounds-but salt dissolves in water sand doesn't. Vital difference in physical properties gives great way to separate them.

Answer 4

Grind mixture to make sure salt crystals are small so will dissolve easily. put mixture in water and stir. Salt will dissolve but sand won't. Filter mixture. Grains of sand won't fit through tiny holes in filter paper, so collect on paper instead. Salt passes through filter paper as it's part of solution Evaporate water from salt that it forms dry crystals.

Answer 5

used to separate out liquid from solution. Solution is heated. Part of solution that has lowest boiling point evaporates first. Vapour is then cooled, condenses (turns back into liquid) and is collected. Rest of solution is left behind in flask.

Answer 6

Can use simple distillation to get pure water from seawater. Water evaporates and is condensed and collected. Eventually you'll end up with just the salt left in flask. Problem with simple distillation is you can only use it to separate things with very different boiling points. If temperature goes higher than boiling point they will mix again.

Answer 7

You need another to separate them-like fractional distillation.

Answer 8

If have mixture of liquids you can separate using fractional distillation.

Answer 9

Put mixture in flask and stick fractionating column on top. Then heat it. Different liquids will all have different boiling points-so will evaporate at different temperatures. Liquid with lowest boiling point evaporates first. When temperature on thermometer matches boiling point of liquid will reach top of column.

Answer 10

Liquids with higher boiling points might also start to evaporate. But column is cooler towards top. So they only get part of the way up before condensing and running back down towards the flask. When fist liquid has been collected, you raise temperature until next one reaches top.

Answer 11

electrons, these could be removed from charge. Dalton's theory wasn't quite right. Thomson suggested atoms were spheres of positive charge with tiny negative electrons stuck in them-plum pudding model. His measurements of charge and mas showed atom contained small electrons.

Answer 12

matter was made up of tiny spheres (atoms) that couldn't be broken up, be Dalton thought each element was made from different types of atoms.

Answer 13

Showed atom as ball of positive charge with electrons stuck in it.

Answer 14

he fired alpha particles at thin gold foil-alpha scattering experiment. From plum pudding model expected them all to go through sheet or slightly deflected. Most went through some more deflected more than expected, few deflected back the way they came. Plum pudding model proved wrong.

Answer 15

due to some alpha particles coming back scientist knew most mass of atom was concentrated in centre in tiny nucleus. Nucleus had positive charge since repelled positive alpha particles. Because nearly all went through most of atom was empty space-first nuclear atom

Answer 16

The nuclear model that resulted from alpha particle scattering experiment was a positively charged nucleus surrounded by cloud of negative electrons.

Answer 17

electrons orbiting nucleus do it in certain distances called energy levels in fixed shells and aren't anywhere in between and distances form nucleus. His theoretical calculations agreed with experimental data. After Bohr further experiments found protons subatomic particle to make the nucleus positively charged.

Answer 18

proved existence of neutron explained imbalance between atomic and mass numbers. and had charge of hydrogen nucleus.

Answer 19

the nucleus' radius is 10,000 times smaller than the atom. radius of atom is 1*10 to the power of -10 m. if electrons gain energy by absorbing EM radiation have to move to higher energy level far from nucleus (opposite with other way round).

Answer 20

Always filled first-closest to nucleus. 1st shell 2 2nd shell 8, 3rd shell 8.

Answer 21

20th century when protons and electrons were discovered.

Answer 22

Relative atomic mass groups. Done in periodic pattern was noticed in properties. Where 'periodic table' comes from. Some elements were grouped in wrong ways in the old arrangement because it only took into account mass not other properties.

Answer 23

Took 50 elements and arranged them into his own table of elements which overcame some of the earlier problems. Put them mainly in atomic mass but did switch order if properties meant it should be changed. e.g. I has a small mass but is placed after Te as it has similar properties to elements in the group.

Answer 24

To fill in elements in the future with similar properties. Could predict the properties. When they were found they were filled in the pattern help confirm Mendeleev's ideas. He made good predictions about physical and chemical properties of element called ekasilicon now called germanium.

Answer 25

Isotopes of same element have different atomic masses but have the same chemical properties so occupy same position on periodic table.

Answer 26

increasing atomic number in repeating patterns in properties occur periodically. elements with similar properties form columns (vertical columns called groups). Group tells you how many electrons on outer shell. reactions depend on electrons on outer shell.

Answer 27

non-metals on right, metals on left.

Answer 28

e.g. group 1 reactivity decreases as go down. rows called periods. New period represents new outer shell.

Answer 29

form positive ions, towards bottom left of table, most elements in table are metals, non-metals at far right and top of periodic table, non-metals don't generally form positive ions when react.

Answer 30

Atoms generally react to make full outer shell, via losing, gaining or sharing electrons, metals to left of table don't have may electrons to remove, metals to bottom of table have outer shell electrons which are long way from nucleus do feel weaker attraction. Both effects mean not much energy is needed to remove electrons so is feasible for elements to react to form positive ions with full outer shell.

Answer 31

non-metals find harder to form positive ions. to right of table have lots of electrons to remove to get full outer shell, or towards top, where outer electrons are close to nucleus so feel strong attraction. Far more feasible for them to either share or gain electrons to get full outer shell.

Answer 32

metals:strong, can be bent or hammered into different shape (malleable), high boiling points. We know the rest, non-metals:no metallic bonding don't tend to exhibit same properties as metals. Tend to be dull looking more brittle aren't always solid at room temperature, don't generally conduct electricity and often have lower density.

Answer 33

centre of table, typical metals can have more than 1 ion, often coloured so compounds contain them of colourful, good catalysts

Answer 34

have 1 electron on outer shell-reactive and similar properties, often soft and low density. Increasing reactivity as you go down, more easily lost as attraction between nucleus and electron decreases-electron further away from nucleus further down group, low melting and boiling points, higher relative atomic mass.

Answer 35

don't need much energy to react to form outer shell, easy for them to lose outer electron that they only ever react from ionic compounds. Compounds are generally white solids that dissolve in water to form colourless solutions.

Answer 36

react vigorously to produce hydrogen gas and metal hydroxides-salts that dissolve in water to produce alkaline solutions. More reactive lower down group-more violent in reaction, amount of energy given out by reaction increases down group-reaction with potassium releases enough energy to ignite hydrogen.

Answer 37

react vigorously when heated in chlorine gas to form white metal chlorine salts, as go down group reactivity increases so reaction with chlorine gas gets more vigorous.

Answer 38

react with oxygen to form metal oxide.

Answer 39

group 1 more reactive than transition metals-react more vigorously with water, oxygen or group 7 elements. Also much less dense, strong and hard than transition metals, and have much lower melting pints. e.g. manganese melts at 2000 degrees, sodium melts at 98 degrees.

Answer 40

colourful, as go down group become less reactive-harder to gain extra electron, because outer shell's further down nucleus, higher melting and boiling point, have higher relative atomic mass. All in group react in similar way because 7 electrons in outer shell.

Answer 41

Form 1-ions called halides, from called ionic structures

Answer 42

Displacement reaction occurs between more reactive halogen and salt of less reactive one. e.g. chlorine can displace bromine and iodine from an aqueous solution, of its salt (bromide or iodide). Bromine will also displace iodine because of trend in reactivity.

Answer 43

have 8 electrons in outer shell, apart from helium which has 2. Don't give up or gain electrons to become more stable. Means more or less inert-don't react much at all. Exist as monatomic gases-single atoms not bonded to each other, all elements in group 0 are colourless gases at room temperature, not flammable.

Answer 44

Boiling points of noble gases increases as go down group along with increasing relative atomic mass.

Answer 45

Increase in boiling points is due to increase in number of electrons in each atom leading to greater intermolecular forces between them which need to overcome. More intermolecular forces for small molecules.

Answer 46

Helium, neon, argon, krypton, xenon, radon.

Answer 47

Fluorine, chlorine, bromine, iodine, astatine

Answer 48

Lithium, sodium, potassium, rubidium, caesium, francium.

module 1 Flashcards

(72 cards)