Chemistry unit 1 Flashcards
what is an example of a non metal
carbon, bromine, neon
where are nonmetals found in the periodic table
the right side of the stair case
what is an example of a semi metal
boron, silicon, arsenic
what are semi metals
substances that display both non-metallic and metallic properties
what is an example of a metal
silver, nickel, lead
where are metals found in the periodic table
the left side of the stair case
name 4 reasons most water not drinkable
because it contains
- dissolved salts
- microorganisms
- pollutants e.g sewage
- dissolved gases e.g co2
what are the 3 main stages to purifying water
-sedimentation
-filtration
-chlorination
what is sedimentation
allowing solids to sink to the bottom of the water in order to filter them out
what is filtration
when water is passed through a filter bed
what is a filter bed
a mixture of stones, gravel, coarse and fine sand that remove solids in water to allow only bacteria and viruses to remain
what is chlorination
chlorine is added to water to kill bacteria
why is sulfur dioxide bubbled through water
to remove excess chlorine
how is drinking water transported
by underground sealed pipes
name 3 advantages of fluoridation
-decreases enamel decay
-makes teeth stronger
-prevents cavities
what is fluoridation
Fluoridation is the addition of fluoride to a water supply
name 3 disadvantages of fluoridation
-more effective in toothpaste than in water
-too much fluoride can cause fluorosis
-can cause bone cancer in males
name 2 people that may support the addition of fluoride to water
-dentists
-health workers
what is desalination
obtaining pure drinking water from dirty or salty water
how is desalination done
using reverse osmosis filters to filter the dirty water under pressure
give 3 reasons why desalination is bad
-expensive
-uses lots of energy
-the by-product is very salty water and so must be disposed of carefully
what is distillation
the process of separating liquids or dissolved solids from a liquid mixture by using boiling and condensation
what is hard water
hard water is water that has a lot of calcium compounds dissolved in it
why can water be hard
because sometimes water passes through calcium containing (gypsum) rocks that dissolve into the water making it hard
how do you remove the hardness from temporary hard water
by boiling it
name 3 advantages of hard water
-some people prefer the taste
-calcium is good for bones
-good for brewing beer
name 3 disadvantages of hard water
-limescale build up can damage metal appliances
-pipes can become blocked from limescale
-scum forms in reaction with soap
how is limescale formed
calcium ions + hydrogen carbonate ions –> calcium carbonate (limescale) + carbon dioxide + water
how to make hard water not hard
using an ion exchange column
how does an ion exchange column remove water hardness
the column is filled with a resin that holds sodium ions. as hard water passes through the calcium ions and sodium ions swap. the water that comes out contain no calcium ions so is no longer hard.
what is solubility
a soluble particle is one that can dissolve into a substance
draw a flow chart outlining the main steps of the purification of water
reservoir -> sedimentation tank -> filtration -> addition of chlorine ->clear water tank -> storage reservoir -> mains supply
what is the inner core of the earth made of
solid iron and nickel due to the high pressure
what is the outer core of the earth made of
liquid iron and nickel
what is the mantle of the earth made of
semi-molten rock that can behave like a liquid
what is the crust of the earth made of
solid outer layer floating on the mantel
how thick is the crust of the earth
between 5 and 70 km thick
where in the earth is the magnetic field produced
in the outer core
who in 1915 first suggested the idea of continental drift
Alfred Wegener
what is continental drift
the gradual movement of the continents across the earth’s surface through time.
why did Alfred Wegener think that all the continents were once all one piece?
- the jigsaw fit of the coastlines of africa and south america
- similar rocks were found at both sites
- fossil animals found only South America and Africa, could be found on many continents.
give an example of a strong alkali
bleach pH 13
give an example of a weak alkali
baking soda pH 9
give an example of a weak acid
tomato juice pH 4
give an example of a strong acid
gastric acid pH 1
finish the equation
acid + metal –> _________ + _______
salt and hydrogen
finish the equation
acid + metal hydroxide/ oxide –> _________ + _______
salt and water
finish the equation
acid + metal carbonate –> _________ + _______ + _________
salt and water and carbon dioxide
what is the name of a salt created from hydrochloric acid
chloride
what is the name of a salt created from sulfuric acid
sulfate
what is the name of a salt created from nitric acid
nitrate
what are titrations
controlled reactions between acids and alkalis
what can titrations be used to calculate
unknown concentrations
what is the gas test for hydrogen
burns with a squeaky pop
what is the gas test for carbon dioxide
turns limewater cloudy
what is the gas test for oxygen
re-lights a glowing splint
what 4 factors can affect the rate of chemical reactions
- temperature (kinetic energy)
- concentration
- surface area
- adding a catayst
how does raising the temperature impact the rate of reaction
- makes particles collide more frequently as they have more kinetic energy
- makes it more likely that collisions result in reactions as the particles collide with more energy
how does increasing the concentration impact the rate of reaction
- a higher concentration means there are more particles in a given volume
- this means more successful collisions so a faster rate
how does adding a catalyst impact the rate of reaction
- speeds up reaction with being chemically changed
- allow particles to collide in different ways
- increases the rate of reaction
why is there a gradual loss of mass in some chemical reactions
because gas is emitted over time
