Summer Revision 2020 Past Paper Flashcards
Oxidation is the ____ of electrons.
Reduction is the ____ of electrons.
losing
gaining
Why should carbon electrodes be continually replaced?
Because oxygen reacts with carbon in the positive electrodes, forming carbon dioxide.
So they gradually burn away.
How many atoms are joined by one diamond atom?
One atom is joined by 4 other carbon atoms.
What are the 4 physical properties of diamond?
Diamond has a high melting point, high boiling point, is very hard and can’t conduct electricity.
Why is diamond hard?
Because the carbon atoms are held together by STRONG covalent bonds.
Why do giant covalent structures have a high melting/ boiling point?
This is because a large amount of energy is needed to overcome the strong covalent bonds.
What are examples of giant covalent structures?
Diamond,
Graphite,
Silicone Dioxide
In the thermal decomposition of metal carbonates practical, the more ______ the metal is, the more _____ the metal carbonate is.
reactive
stable
How can the stability of metal carbonates be measured in the thermal decomposition of metal carbonates practical?
By heating the carbonate and bubbling the produced carbon dioxide through limewater.
In the thermal decomposition of metal carbonates practical:
The quicker the limewater becomes milky, the greater the ___________________. Meaning the carbonate is ___________.
rate of decomposition
less stable
In the thermal decomposition of metal carbonates practical, you should set up what equipment?
A Bunsen burner, test tubes, tripod and gauze.
After setting up equipment for the _ the student should ____________________ and _____________________ until there is no further change in mass.
collect CO2 with a syringe
heat the metal carbonate
In the thermal decomposition of metal carbonates practical, you should repeat __________________________________.
the experiment on different metal carbonates.
Why should you repeat 3 times in the thermal decomposition of metal carbonates practical?
To reduce anomalies.
What is the equation for moles?
number of moles= mass/ relative formula mass
What is a mole?
The amount of substance that contains the same number of particles as the atoms.
What is the molar volume of gas?
The volume occupied by one mole of gas at room temperature and pressure.
What is the volume of gas of one mole at room temperature and pressure?
24dm3
What is the equation for volume of gas at rtp?
Volume of gas= Number of moles x 24
What are the steps for calculating the mass of chlorine?
- Find moles of gold with the formula: moles= mass/ rfm
- Use the 2:3 ratio to find moles of chlorine.
- Multiply by mr (using cl2)
