1.1 Particle theory & chemical change
Syllabus
The IB guide recommends knowledge of the following in this section:
What does this mean?
The Basics - States of Matter, Kelvin, Changes of State, Mixtures, Equations
States of Matter
You’ll have studied this in Year 7 and 8 Sorry!
Temperature
Temperature and heat are not the same.
Heat is measured in Joules (J).
From now on temperature is measured in Kelvin (K).
Converting is easy since a difference of 1 oC is a difference of 1 K.
So as long as you know 0 K is -273 oC converting is easy.
It's worth knowing that a change of temperature is the same in Kelvin and oC.So, if the temperature rises by 5oC it has also risen by 5 K
Changing State.
Most pupils will have seen heating/cooling curves before.
The plateaus (when the temperature remains the same) are changes of state.
QUESTION
1. 1.When ice is heated why does its temperature not increase during the melting period? What is the energy from the heater being used for if it isn’t raising the temperature?
___________________________________________________________________________________________________________
___________________________________________________________________________________________________________
2. 2. Melting and boiling are endothermic processes. What does this mean?
___________________________________________________________________________________________________________
___________________________________________________________________________________________________________
3. 3. Some substances, CO2 & I2 etc, don’t have a liquid phase. What do we call the 2 missing state changes in the diagram (right)?
__________________________________________________________________________________________
__________________________________________________________________________________________
Video
Elements and compounds.
More Year 8 stuff!
Elements – contain only one type of atom.
Compounds -contain 2 or more types of atoms chemically bonded together in a regular formula.
Mixtures – are irregular. Not every part is the same.
QUESTION
Remember these?
Which are elements, mixtures compounds?
Mixtures.
Homogeneous mixtures are the same all the way through even though the different components aren’t chemically bonded to each other.
Like sugar in a sugar solution.
Heterogenous mixtures are randomly arranged.
Like soil.
QUESTION
Which of these mixtures are homogeneous, which are heterogeneous?
milk,
blood
pizza
body-lotion
banana splits
glue
Video
Equations
Writing about how to balance equations is like dancing about thermodynamics.
Your teacher will remind you how to balance equations – You just need to practise. The first has been done as a reminder.
