Elements, Mixtures and compounds
What is a compound?
A compound is something that is made up of two or more atoms which have been chemically joined to form molecules.
What bond is it when electrons are gained and lost?
Ionic Bonding
What is the ionic solution called that electrolysis is carried out on?
Electrolyte
Zinc+ phosphoric acid --> ??
Zinc + phosphoric acid --> Zinc Phosphate + hydrogen
What is most reactive metal in series?
potassium
A ________________ is a substance that is made up of two or more elements that have physically combined.
Mixture
What is an ion with more electrons than protons?
anion - a negative ion
What is the electrode with a negative charge?
Cathode
How can we tell if a substance is neutral, an alkali or an acid?
An indicator like Litmus paper can be used to indicate if the substance is an Acid or an alkali. Litmus paper can only show the presence of an acid, a neutral or an alkali. Whereas, using a universal indicator or pH paper can show exactly what pH a substance is but you will still need a pH colour chart to tell what exact pH it is.
What is oxidation?
addition of oxygen an element or compound
Loss of electrons
increase in oxidation
All metals are solid at room temperature. True or False?
False, mercury is a liquid at room temperature.
describe the structure of diamond
when carbon atoms form a giant lattice with 4 bonds each
What are the ions that are in electrolysis of solutions and not in melts?
Hydroxides and hydrogens
What is the difference between an acid and an alkali?
An alkali is the name of a base that dissolves in water whilst an acid is something that is the complete opposite of a base. The acid doesn’t dissolve in water.
What are 3 metals lower in reactivity than hydrogen?
silver gold and platinum
How can you separate a mixture of sand and water?
filtration or evaporation
Why can graphite electricity?
each carbon atom has one delocalised electron
What is the half equation for reduction of magnesium?
Mg 2+ + 2e- => Mg
Potassium Carbonate+ acetic acid --> ???
Potassium Carbonate+ acetic acid --> Potassium Acetate+ hydrogen + carbon dioxide
What is produced when you react zinc with nitric acid?
zinc nitrate
When a certain poisonous gas is combined with a chemically active metal, a fine white powdery substance results. The new substance is neither poisonous nor chemically active. Is the powder a mixture or a compound? How do you know?
It is a compound. The substances did not retain their properties when they were combined.
What are 3 properties of ionic compounds?
high M.P./B.P., soluble in water, and conducts electricity in solution
What will happen to the impurities when purifying copper?
impurities will fall into the solution as sludge
What is a neutralisation reaction and state the equation?
A neutralisation reaction is when an acid is added to an alkali. This will produce a salt and water as well carbon dioxide if there is a carbonate.
ACID + BASE ---> SALT + WATER (+ CARBON DIOXIDE)
What three substances need to be present for rusting to occur?
Iron, oxygen, water