chem hw Flashcards
Give 3 examples of substance with a giant covalent structure
Diamond,silicon dioxide and graphite
Explain why some metals are more reactive than others
They lose electrons more easily
A student has three different metals. They want to investigate how the different types of metals cause a different temperature change when added to an acid. Outline a method to do this. Ensure the method leads to a valid conclusion.
Measure a specific mass of the first metal.
Use a measuring cylinder to measure a set volume of acid and pour it into a polystyrene cup.
Measure the temperature of the acid.
Add the first metal to the acid.
Measure the highest temperature reached by the acid.
Repeat the experiment with the other two metals.
Ensure that the following variables are kept constant: mass of metal, particle size of metal, volume of acid, concentration of acid, type of acid, starting temperature and insulation around the cup.
Explain why potassium is more reactive than lithium.
It has more shells/electrons.
It has a weaker attraction from the nucleus to the outer shell.
It is easier to lose the outer shell electron.
Explain why ionic substances conduct electricity when molten.
The ions are free to move and carry charge
Explain why the anode needs to be continually replaced in the electrolysis of aluminium oxide.
Oxygen is produced at the anode.
The oxygen reacts with the anode, which is made of carbon.
Which forms carbon dioxide.
Causing the anode to wear away.
Explain why atoms transfer electrons in ionic bonding.
So the atoms can have full outer shells.
State the information provided by the atomic number of an atom.
The number of protons
Define isotopes.
Atoms of the same element with different numbers of neutrons.
Describe the structure of graphene.
One layer of graphite
State the value of the Avogadro constant.
6.02 x 10²³
When preparing a soluble salt in the laboratory, explain why the mixture is filtered once the reaction is complete.
To remove the unreacted solid.
State the formula of a hydrogen ion.
H⁺
State the observation at the anode and cathode during the electrolysis of ZnCl₂(aq).
Anode - bubbles
Cathode - silvery metal forming
In a reaction, chlorine displaces bromine from a compound. Complete the ionic equation:
Cl₂ + 2Br⁻ →
Cl₂ + 2Br⁻ → Br₂ + 2Cl⁻
