Chemical equations Flashcards
why are elements put into groups
to group together elements that have similar properties
how to represent hydrogen in a symbol equation
H
2
what is the name given to elements in group 2
alkali earth metals
the total mass of reactants=
the total mass of products
name the 4 state symbols
s- solids
l- liquids
g- gases
aq- aqeuous
Balance the equations on sheet of paper!!!
what is fractional distillation
an effective way of seperating miscible liquids, using a fractionating column
-seperation is possible bc of different boiling points of liquids in the mixture
mixtures are
easily seperated
name 3methods mixtures can be seperated
-filtration
-chromatography
-evaporation
state the method of how to seperate a substance in a mixture through chromatography
-draw a line near the bottom of a sheet of filter paper (using a pencil, as the marks insoluble and won’t dissolve the solvent)
-add a spot of ink to the line and place the sheet in a beaker of solvent (water)
-make sure the ink isn’t touching the solvent, so it doesn’t dissolve into it
-place a lid on top of container to stop solvent evaporating
-solvent seeps up the paper, carrying ink with it
state the results that will occur for paper chromatography
-if the dyes insoluble, it will stay on the baseline
-if the dyes reached the top of the paper, take the paper out the beaker and leave it to dry
when would you need to use fractional distillation rather than simple distillation
FD is used when the mixture contains multiple liquids with similar boiling points
describe the technique for filtration
-place a piece of filter paper in a funnel and put the funnel over a beaker
-pour mixture through the funnel
-any insoluble liquids will be caught by the filter paper and its called residue
-any liquid or dissolved substances will pass straight through and is called the filtrate
state 2ways to seperate soluble solids from solutions
-evaporation
-crystallisation
explain evaporation
-pour solution into evaporating dish
-slowly heat the solution (bunsen burner)and the solvent will then be more concentrated. then crystals start to form
-keep heating the evaporating dish until the crystals are dry
explain crystallisation
-pour solution into a evaporating dish and gently heat the solution
-once the solvents evaporated or when crystals form (point of crystallisation) remove dish from heat and leave solution to cool
-salt starts to form crystals as it becomes insoluble in the cold solution
-filter crystals out of solution and leave them in a warm place to dry
why is simple distillation used
-to separate out solutions
describe the process of simple distillation
-solutions placed in a flask and heated to the liquid evaporates into vapour
-vapours then passed into a condenser where it then condenses back into a liquid
-liquids then collected in a beaker
describe the process of fractional distillation
-used to SEPERATE A MIXTURE OF LIQUIDS
-put a mixture in a flask and stick a fractioning column on top and then heat it
-
state the certain amount of number of electrons that are allowed in each shell
1st shell- 2
2nd shell- 8
3rd shell-8
whats the name given to elements in group 0
noble gases
whats meant by an atoms outer shell
shell of electrons furthest from the nucleus
state why halogens become less reactive as you move down group 7 of the periodic table
-as you go down the group atomic radius and SHIELDING INCREASE
-means theres a weaker electrostatic attraction between the nucleus and the electron its trying to gain
-means more energys required for a reaction to occur
name given to elements in group 1 is
alkali metals
what are the properties of group 1metals
-soft
-low density
-very reactive
-weak
-low melting points
lithium +water—–
sodium +water—–
potassium +water—–
lithium +water—– lithium hydroxide +hydrogen
sodium +water—– sodium hydroxide + hydrogen
potassium +water—– potassium hydroxide + hydrogen
what are the physical properties of most non metals
-brittle
-dull
-low melting/boiling points
-lower density
-poor conductors of electricity
