Chemical Reactions
True or false -
In a chemical reaction atoms are not created or destroyed?
True
In a periodic table what are the vertical columns called and what are the horizontal rows called?
Groups - vertical
Periods - horizontal
What is sound?
Like light sound is a wave.
light is a vibration. True or false?
False light is a wave.
Most cells in your body contains a nucleus and you nucleus contains chromosomes... what are chromosomes?
Chromosomes are long, coiled up lengths of molecule called DNA.
What is the relationship between mass and a chemical reaction?
In a chemical reaction mass is not gained or lost
Is it true that elements from the same group have similar properties or react similarly?
True
Example of a longitudinal wave is...?
Sound wave/ a slinky spring when you push the end.
How does a light wave travel?
Light is a wave that travels in a straight line.
How many chromosomes does a a human body cell contain and how much does the egg and sperm carry?
46 chromosomes. 23 each
What is combustion and what is needed for a combustion?
Combustion is burning - a fuel reacts with oxygen to release energy. The 3 things needed for a combustion reaction is 1) Fuel
2) Heat
3) oxygen
What groups are part of reactive metals?
group 1 & 2
How are sound waves caused? and what does sound need to travel through?
Sound waves are caused by vibrating objects.
Sound needs a medium to travel through because something has to pass on the sound vibrations.
What are transverse waves? ( light is a transverse wave)
Like waves in water, light waves are transverse waves — they have undulations at right angles to the direction the wave is travelling in.
What is a characteristic feature and what are the 2 types of it?
Any difference between a species is known as a characteristics and the 2 different types of characteristics are environmental and inherited.
What is endothermic and exothermic? give an example for each
An exothermic reaction is one which transfers energy to the surroundings and an endothermic reaction is one where energy is taken in from the surroundings. Example for exothermic is an hand warmer and an example of an endothermic is a sports injury pack
What 3 groups are the most reactive?
Group 1 ,2 & 7
What is the reason sound cant travel in space?
Sound can’t travel in space, because it’s mostly a vacuum (there are no particles).
Why is it a good thing that light waves don't need particles to travel?
Light waves don’t need particles to travel. This is a good thing — light from the Sun has to travel through space (where there aren’t many particles) to reach Earth.
Clearly elaborate what the term natural selection means with an example.
This process in which a characteristic gradually becomes more (or less) common in a population is known as natural selection. An example of a natural selection is when there are brown and white rabbits in a snowy area the brown rabbits are going to be the main target because the brown rabbits would be more visible to the predator and as the brown rabbit decrease drastically the white rabbits would increase.
What is a thermal decomposition? Include an example
Thermal decomposition is when a substance breaks down into at least 2 other substances when heated. Example - carbon carbonate -> copper oxide + carbon dioxide.
How can you predict patterns in group 7 elements?
As you go down in the group the elements get less reactive.
From the 3 states of matter order them in fastest to slowest sound travels through.
1) Solid
2) Liquid
3) Gas
Where does light travel in the fastest?
Light travels the fastest in vacuum because there are hardly any particles that will get in its way. Light travels so fast in vacuum that there is nothing else in the world that travels faster than the speed of light in a vacuum
What is extinction and how does it affects us humans?
if the environment changes in some way, some organisms may struggle to compete successfully for the resources they need to survive and reproduce.
If this happens to a whole species, then that species is at risk of becoming extinct. Extinct means that there are none of them left at all (like the woolly mammoth).
Humans rely on plants and animals for food. So if they go extinct we wont be able to get most of our resources.