Chemistry - topic 1 Flashcards
What is sublimation?
When a solid becomes a gas straight from heating rather than becoming a liquid first.
A pure substance is what?
Only consists of one element or compound.
What is a mixture?
Two or more different substances, not chemically joined together
What is an atom?
The smallest part of an element that can exist
What is filtration used for?
To separate an insoluble solid from a liquid.
What are the 3 steps to filtration?
Step 1:
Have one beaker with a mixture of a solid and a liquid and another with filter paper and a funnel
Step 2:
The solid and liquid mixture Is then poured into the filter funnel.
Step 3:
The liquid drips through the filter paper but the solid particles are caught in the filter paper
What is crystallisation used for?
To produce solid crystals from a solution.
What are the 3 steps for crystallisation?
Step1:
The solution is placed in an evaporating basin and heated with a Bunsen burner.
Step 2:
The volume of the solution has decreased because some of the water has evaporated. Solid particles begin to form in the evaporating basin.
Step 3:
All the has evaporated, leaving the crystals behind.
What is simple distillation used for?
To separate a solvent from a solution.
What are the 3 steps to simple distillation?
Step 1:
Salty water is heated
Step 2:
The water vapour cools in the condenser and drips into the beaker.
Step 3:
The water has condensed and is now in the beaker and the salt stays behind.
What is fractional distillation used for?
To separate different liquids from a mixture of liquids.
Why does fractional distillation work?
vapours rise through a column which is hot at the bottom, and cold at the top
vapours condense when they reach a part of the column that is below the temperature of their boiling point
the liquid flows out of the column
