7F Reactions Flashcards
On which side of the Periodic table are metals found?
Left side
Why are metals good for making musical instruments?
They are sonorous (rings or chimes when hit)
What does malleable mean?
Can be bent or hammered into shape, flexible
True or false? “Metals are used in electrical wires because they are electrical insulators.”
False – metal are electrical conductors
Why do metals have high melting and boiling points?
Bonds holding the metal atoms together are very strong and require lots of energy to break them apart
What is an alloy?
A mixture containing at least one metal
Why are alloys stronger than pure metals?
Different sized atoms and are not able to slide over each other easily
Why do metals feel heavy for their size?
They are very dense
On which side of the Periodic table are non-metals found?
Right side
Which type of non-metal will have the lowest melting and boiling points?
Gaseous non-metals
What will non-metals do when bent?
Snap or shatter
What is an electrical insulator?
A material which stops electricity from passing through
Which non-metal will conduct electricity?
Graphite
Why are the ends of drill bits covered in diamond?
Diamond is the hardest substance on Earth
Why are non-metals dull?
They are rough so light is reflected in different directions
Why are solid non-metals the most dense?
Particles are closer together
Give two ways we know that a chemical reaction is happening.
Gas produced (fizzing), colour or temperature change, new products
What are the two products of a reaction between a metal and acid?
Salt and hydrogen
Which part of the salt’s name comes from the metal?
The first part, e.g. sodium chloride where sodium is the metal
What type of salt is produced by nitric acid?
Nitrate
What type of acid produces a chloride salt?
Hydrochloric acid
What salt will be produced by potassium and nitric acid?
Potassium nitrate
Why does the reaction between a metal and acid produce hydrogen gas?
All acids contain hydrogen
How do we test for hydrogen gas?
A lit splint held in the gas will ignite with a squeaky pop
Define inert
Unreactive (will not take part in reactions)
What do we mean when we say that an element is “reactive”?
It will take part in reactions and react with other substances
What is the reactivity series?
A list which orders metals in order of how reactive they are
Give an example of an unreactive metal.
Copper, iron, lead, gold
Which two non-metals are included in the reactivity series?
Carbon and hydrogen
How does a reactive metal react when added to dilute acid?
Reacts quickly to produce lots of hydrogen gas
Give an example of a metal which reacts with dilute acid, but not with water.
Copper, magnesium, iron, zinc, silver
How can less reactive metals be extracted from their metal ores?
Heating with carbon
What is a displacement reaction?
A reaction where a more reactive metal takes the place of a less reactive metal in a compound
What does bond strength depend on?
Reactivity – more reactive metals form stronger bonds
Why does potassium displace zinc in zinc chloride?
Potassium is more reactive than zinc
Why will calcium displace copper in copper chloride?
Calcium is more reactive than copper
Why can copper be extracted from its ore using carbon?
Copper is less reactive than carbon
What are the products of the reaction between carbon and copper oxide?
Copper and copper oxide
What are the two signs that a displacement reaction has occurred?
Colour change, bubbles, temperature change
What is an oxidation reaction?
When an element reacts with oxygen
Give an example of an oxidation reaction that is not useful to us.
Rusting, oxidation of food
What are the two conditions needed for iron oxide to form?
Water and oxygen
Why is rust a problem when building bridges out of iron?
Rust is weak and brittle
Give an example of a useful oxidation reaction.
Combustion
Describe the test for oxygen
Hold a glowing splint in the gas, it will relight
How does paint help prevent rusting?
Acts as an extra barrier between the metal and air
Name a metal that would be unsuitable for covering iron.
Any metal that is a lot more reactive than iron, e.g. potassium, calcium, sodium
What do acids produce when they dissolve in water?
H+ (hydrogen ions)
What do alkalis produce when they dissolve in water?
OH- (hydroxide ions)
State two properties of alkalis.
Feel soapy and slippery, taste bitter
Give a use of borax.
Laundry cleaner, surface cleaner
Which alkali is used to make dough rise?
Baking soda
Which acid is found in citrus fruits?
Citric acid
What is an indicator?
Changes colour depending on whether it is added to an acid or alkali
What range does the pH scale have?
Jan-14
What is an indicator?
A coloured dye which will change colour depending on whether it is added to an acidic or alkaline solution
Why are the pieces of red cabbage crushed with a pestle and mortar?
To release the purple dye from the leaves
What equipment is used to remove the red cabbage pieces from the solution?
Filter paper and filter funnel
How will you decide which colours show acidic, alkaline and neutral solutions?
Comparing the results to last lesson’s practical
How do you know the pH value of each solution?
By using the same solutions from last lesson
Why is universal indicator a useful indicator?
Tells us how strong an acid or alkali is
Why are some indicators not very useful if you have more than one acidic solution?
We could not tell which acids were strong or weak
How can we make red cabbage indicator paper?
By soaking paper in red cabbage indicator
Universal indicator turns what colour in a strong alkali?
Purple
Red cabbage indicator turns what colour in a weak acid?
Lilac
State one similarity between universal indicator and red cabbage indicator.
They both tell us about the strength of the acid or alkali
What are the two colours of litmus paper?
Red and blue
What happens to both types of litmus paper when added to neutral solutions?
Do not change colour
What pH range will turn methyl orange yellow?
pH 4 – 14
What pH range will turn phenolphthalein colourless?
pH 1 – 7
Why are some indicators more useful than others?
The wider range of colours tells us about the strength of an acid or alkali, allows us to distinguish between different pH
What is a neutralisation reaction?
A reaction between an acid and alkali
What are the products of a neutralisation reaction?
Salt and water
Give an example of a common acid.
Hydrochloric acid, nitric acid, sulphuric acid
Give an example of a common alkali.
Sodium hydroxide, potassium hydroxide
What type of salt is made by hydrochloric acid?
Chloride salt
State two uses of neutralisation.
To treat bee and wasp stings, to treat excess stomach acid, to make fertilisers
How are bases and alkalis similar?
They both neutralise acids
How are bases and alkalis different?
Bases are insoluble (do not dissolve in water), alkalis are soluble (dissolve in water)
What is heartburn?
Where excess stomach acid rises up the oesophagus and causes a burning pain
How is the stomach protected from its acid?
It has a mucus lining
What pH value is stomach acid?
pH 2
What type of reaction occurs when an antacid reacts with stomach acid?
Neutralisation
Why do you think medicine to treat heartburn is called an antacid?
They neutralise the acid to get rid of it, like an “anti” acid
What are the products of the reaction between an antacid and stomach acid?
Salt, water and carbon dioxide
Give an example of an ingredient found in antacids.
Sodium bicarbonate, calcium carbonate
Why must control variables be kept the same?
So that they do not affect the outcome of the investigation
What are two features of a good method?
Step-by-step instructions, how to keep control variables the same
