Y10 Recall quiz questions Flashcards
Give every day use of endothermic reaction
sports injury packs
what sub-atomic particle was discovered first?
the electron
Before electrons were discovered, what were atoms thought to be?
indivisible
Before electrons were discovered, atoms were thought to be what
tiny spheres
What model did the discovery of the electron lead to?
the plum pudding model
What was the plum pudding model?
that the atom was a ball of positive charge with negative electrons embedded in it
What is the energy of the products compared to reactants in an exothermic reaction
less
What is the energy of the products compared to reactants in an endothermic reaction
more
What is activation energy
Minimum energy that particles must have for a reaction to occur
What is an exothermic reaction?
energy is transferred to the surroundings
What happens to the temperature of an exothermic reaction?
temperature increases
What is an endothermic reaction?
energy is taken in from the surroundings
What happens to the temperature of an endothermic reaction?
temperature decreases
How can you tell what a reaction profile represents
if reactants is above products it is exothermic and if it is below then it is endothermic
How does filtration work?
Pass through filter paper, liquid passes through, insoluble particles get caught by the filter paper
Where are the reactants found in an equation?
Left-hand side
Where are the products found in an equation?
Right-hand side
What is chromatography?
a method used to separate the coloured compounds in a mixture
How long have the proportions of the gases in the atmosphere been like today?
200 million years
What type of bond is formed between a metal and non-metals?
ionic
What type of bond involves gain or loss of electrons?
ionic
What happens when a metal and a non-metal form an ionic bond?
electrons are transferred (lost/gained)
What is the group number if an element forms a -2 ion?
6
If an atom loses two electrons to form an ion what charge will the ion have?
+2
Why do metals and non-metals form ionic bonds?
to achieve a full outer shell and be stable
What are the gases found in today’s atmosphere? cownn
nitrogen, oxygen, carbon dioxide, water vapour , noble gases
What are the percentages of the gases in today’s atmosphere?
80% nitrogen,20% oxygen, less than 1% other gases
What planets is the earth’s early atmosphere suggested to be like?
Mars and Venus, consisting mainly of carbon dioxide and little or no oxygen
What other gases were released by volcanoes?
Nitrogen, Methane, Ammonia
Which one is NOT one of the ways carbon dioxide levels were reduced?
Plants carry out respiration
Why did the percentage of oxygen increase in the early atmosphere?
Algae and plants released it during photosynthesis
What is the correct word equation for photosynthesis?
Carbon dioxide + water –> glucose + oxygen
When did algae first appear?
2.7 billion years ago
What did the increase in oxygen from algae and plants lead to?
Enabled animals to evolve
What do particulates contribute to?
global dimming (smog)
What are the particles like in an ionic bond?
Oppositely charged ions (positive and negative ions)
What is a carbon footprint?
The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event
How can a carbon footprint be reduced?
By reducing emissions of carbon dioxide and methane by reducing use of cars (cycle/ walk instead), eat less meat, recycle
What type of bonding is likely to occur between group 1&2 metals with group 6&7 non-metals?
ionic
How are oxides of nitrogen produced when burning a fuel?
High temperature in car engines cause oxygen and nitrogen in the air to react
How is sulfur dioxide produced when burning a fuel?
Fuels contain sulfur as an impurity, when the fuel is burnt the sulphur reacts with Oxygen to form sulphur
what do oxides of nitrogen and sulfur dioxide lead to?
respiratory problems and acid rain
What does carbon dioxide contribute to?
global warming
What are the issues with the production of carbon monoxide?
poisonous
Why is it hard to detect if carbon monoxide is formed?
it is odourless and colourless so it can’t be seen
What is a pure substance?
A substance made up of single element or compound, not mixed with any other substances
What are the boiling and melting points like for pure substances?
At a fixed (specific) temperature
What are the boiling and melting points like for an impure (mixture) substances?
over a range
What is a formulation?
A mixture that has been designed as a useful product
Which method is used to separate dyes?
Chromatography
What type of force exists between oppositely charged ions?
Electrostatic force
What type of structure is found in ionic compounds?
Giant lattice
What formula would the following ions have: Mg2+ and O2?
MgO
Why do ionic compounds conduct when melted or dissolved in water? (walk,backpack)
Ions can move and carry a charge
What do atoms do in a covalent bond to get a full outer shell?
Share pairs of electrons
What gases can be released into the atmosphere when a fuel is burnt?
Carbon monoxide, sulphur dioxide, oxides of nitrogen
What type of bonding is formed between just non-metals?
Covalent
How are covalent bonds shared?
Electrons are shared
How many electrons does each atom donate in a single covalent bond?
1
What is the strength of a covalent bond?
Strong
What experiment led to idea that mass of the atom was concentrated in the centre?
Alpha Scattering Experiment
What would happen with the alpha particle experiment if the plum pudding model was correct?
Particles to pass straight through or slightly deflected
Why did most of the alpha particles go straight through?
Atom is mostly empty space
Why did some alpha particles deflect more than expected?
Alpha particles hit a positively charged centre and repelled
Why did very few alpha particles deflect backwards?
Alpha particles hit a concentrated mass
Why do atoms have no overall electrical charge?
An atom has the same number of positive protons as negative electrons
What is an isotope?
The same element but with the same number of protons but different numbers of neutrons
Why is the relative atomic mass of chlorine not a whole number
Has more than one isotope
How can we reduce the emissions of carbon dioxide and methane?
Reduce use of cars (cycle/ walk instead), Eat less meat, Recycle
What is a major source of atmospheric pollutants? (COF)
Combustion of Fuels
What do most fuels contain?(c,h,ss)
carbon, hydrogen and some contain sulphur
What are the melting point of giant covalent structures?
High
Why can diamond not conduct electricity?
No ions or delocalised electrons
Why can graphite conduct electricity?
Contains delocalised electrons that are able to move and carry a charge through structure
What is graphene?
One layer of graphite
What are carbon nanotubes?
A cylinder tube of graphite
What are fullerenes?
A hollow ball with hexagons of carbon atoms
What human activities are increasing the level of carbon dioxide and methane
Farming cattle,landfill sites,deforestation
Why don’t simple covalent molecules conduct electricity?
No ions or delocalised electrons
What is the difference between graphene and graphite?
graphite has layers
Why can graphite conduct electricity?
Contains delocalised electrons able to move and carry a charge through structure
What do scientists believe human activity will do to the temperature of the earth?
Increase it, leading to climate change
Why is it difficult to predict global warming?
speculation of the future and opinion presented in media
What is the issue with climate change presented in the media?
Based on opinion, only parts of evidence is reported and can be biased
What is climate change?
Increase in average global temperature
What are the main four potential effects of global climate change?
glacier and polar ice melting, sea levels rising, patterns in rainfall changing leading to floods or droughts, habitats changing
How are the atoms linked in a polymer?
Strong bonds between the atoms
What happens to the boiling point of simple covalent molecules with increasing size?
Increases because there are more of the weak intermolecular forces present
What was the first fullerene discovered?
Buckministerfullerene
Why can metals conduct electricity?
Contains delocalised electrons able to move and carry a charge through structure
Why are metals malleable?
When a force applied the layers of atoms can slide over each other
Why are pure metals not suitable for many uses?
Too soft
What is an alloy?
A mixture of metals
Why are alloys harder than the pure metal?
Different sized atoms disrupt the layers
What is the state symbol for a solid?
(s)
What is the state symbol for a liquid?
(l)
What is the state symbol for aqueous?
(aq)
What is the state symbol for gas?
(g)
What happens to the bonds/ forces when melting?
weakened
What happens to the bonds/ forces when boiling?
broken
What is gained during melting/ boiling?
energy
What is the process called for: liquid –> gas?
evaporation
What is the process called for: gas –> liquid?
condensation
What is the process called for: liquid –> solid?
freezing
What is the process called for: solid –> liquid?
melting
How can you tell how many elements are present in a product?
count the number of capital letters
How can you tell how many atoms are present in a product?
add the number (including the element without numbers which have 1 atom)
What is the atomic mass (Ar)?
Top number on the periodic table
What is the relative formula mass (Mr)?
Sum of the relative atomic masses of the atoms in the formula
What is the law of conservation of mass
No atoms are lost or made during a chemical reaction so the mass of the products equals the mass as the reactants
How do the relative formula masses of the reactants compare to the products?
they are equal
What sub atomic particle is involved in bonding (chemical reactions)?
Electrons
How many electrons are in each shell?
2,8,8
What holds atoms of elements together in compounds?
chemical bonds
How were early periodic tables arranged (Newland and Mendeleev)?
Atomic mass
How is the modern periodic table ordered?
in order of atomic number
What are elements with similar properties placed in?
groups
What do all elements in the same group have in common?
the same number of electrons in the outer shell
Where are the metals found in the periodic table?
left hand side
Where are the non-metals found in the periodic table?
right hand side
What is an ion?
a charged particle
What types of ions do metals form?
Positive, as they lose electrons to get a full outer shell
What types of ions do non-metals form?
Negative, as they gain electrons to get a full outer shell
What elements are founds in the block of the periodic table between groups 2&3?
Transition metals
What are the elements in group 0 called?
Noble gases
Why are Noble gases unreactive/inert
As they have a full outer shell
What happens to the boiling point of the Noble gases as you go down the group (increase in relative atomic mass)?
Increases
What are the elements in group 1 called?
alkali metals
How many electrons do all group 1 elements have in their outer shell?
1
What are the elements in group 7 called?
Halogens
How many electrons do all group 7 elements have in their outer shell?
7
What state is chlorine at room temperature and its colour?
yellow/green gas
What is the charge on a halide ion?
-1
What sort of compounds do halogens form with other non metals?
covalent
How many elements are present in H2S04?
3
Describe how magnesium and oxygen form an ionic bond
Magnesium loses 2 electrons and Oxygen gains 2 electrons
What are the properties of diamond?
Cannot conduct electricity and has high melting points/ high boiling points
Why does diamond have a high melting point?
Require lots of energy to overcome strong covalent bonds between the atoms
Why can diamond not conduct electricity?
No ions or delocalised electrons
Describe the structure and bonding in diamond
Giant lattice structure and strong covalent bonds between atoms
What are the properties of graphite?
Can conduct electricity, soft & slippery and high melting points/ high boiling points
Why does graphite have a high melting point?
Strong covalent bonds between the atoms and require lots of energy to overcome
Why can graphite conduct electricity?
Contains delocalised electrons able to move and carry a charge through structure
How many atoms are present in H2SO4?
7
What is the atomic mass (Ar)?
Top number on the periodic table
What is the relative formula mass (Mr)?
Sum of the relative atomic masses of the atoms in the formula
What is the law of conservation of mass
No atoms are lost or made during a chemical reaction so the mass of the products equals the mass as the reactants
How do the relative formula masses of the reactants compare to the products?
they are equal
Why could the mass of products be less than the mass of the reactants?
A gas is made which can escape
Why could the mass of products be more than the mass of the reactants?
When a gas is added to a reactant
What is concentration measured in?
Grams per decimetre cubed (g/dm3)
How do you calculate concentration?
concentration = mass ÷ volume
What units does mass have to be in when calculating concentration?
grams (g)
What units does volume have to be in when calculating concentration?
decimetre cubed, dm3
How do you convert cm3 to dm3?
÷ by 1000
What is the balanced equation for photosynthesis?
6CO2 + 6H2O –> C6H12O6 + 6O2
What useful substances have been formed as carbon dioxide decreased? (l,c,n)
Limestone, crude oil, natural gas
What type of gas maintains the temperature on earth to be high enough to support life?
Greenhouse gases
What greenhouse gases are increased due to human activity?
Carbon dioxide and methane
What human activities are increasing the level of carbon dioxide and methane?
Farming cattle, rice paddy fields, landfill sites
What do scientists believe human activity will do to the temperature of the earth?
Increase it, leading to climate change
What does uncertainty mean?
the interval within which the true value of a quantity can be expected to lie
What is crystallisation?
A way to separate a dissolved solid from a solution by evaporation to leave crystals of the solid
A method used to separate two or more liquids?
fractional distillation
What theory is given for the earth’s early atmosphere
First billion years gave rise to volcanic activity and released gases and water vapour condensed to form oceans
What planets is the earth’s early atmosphere suggested to be like
Mars and Venus, consisting mainly of carbon dioxide and little or no oxygen
