Elements, Compounds, and Mixtures Flashcards
What is the atom?
An atom is a type of miniscule, minute particle; they’re so small that you can’t see them directly.
What is the Dalton Model?
- All matter is made up of atoms
- There are different types of atoms
- Each element contains a different type of atom
What is an element?
An element is a substance that contains only one type of atom. All elements have different properties. For example, oxygen is a colourless gas. There are over 100 different elements and each element has a symbol.
What does the Periodic Table show?
The Periodic Table shows all of the elements we have discovered. The first version of the Periodic Table was put together by a scientist called Mendeleev.
What is a mixture?
A mixture contains two or more different substances that are not chemically joined up so you can separate them using physical methods.
What is dissolving?
It is a common way mixtures are made. When you add a solid to a liquid the bonds holding the solid particles together sometimes break. Then the solid particles mix with the particles in the liquid forming a solution.
What is a solute?
The solid being dissolved.
What is a solvent?
The liquid it’s dissolving into.
What is a solution?
A mixture of a solute and a solvent that does not separate out.
What happens in filtration?
You filter through filter paper in a funnel.
What happens in evaporation?
You evaporate in an evaporating dish.
What is distillation used for?
Distillation is used for separating out a mixture of a solid and a liquid.
What is fractional distillation used for?
It separates mixed liquids.
What happens in fractional distillation?
Different liquids will boil off at different temperatures, around their own boiling point.
What does the fractionating column do in fractional distillation?
The fractionating column ensures that the wrong liquids condense back down, and only the liquid properly boiling at the temperature on the thermometer will make it to the top.
What happens in chromatography?
Different dyes in ink will wash through paper at different rates. Some will stick to the paper and others will remain dissolved in the solvent and travel through it quickly.
What is chromatography used for?
It is ideal for separating dyes in inks.
What happens in method 1 of chromatography?
1) Dots of ink are put onto chromatography paper.
2) A wick is cut from part of the paper.
3) The solvent washes the dyes through the paper.
What happens in method 2 of chromatography?
1) Put spots of ink onto a pencil baseline on chromatography paper
2) Roll the sheet up and put it in a beaker.
3) The solvent seeps up the paper, carrying the ink dyes with it.
4) Each different dye will form a spot in a different place.
5) You can compare a forged ink to a known ink to see which it is.
What are compounds?
They contain two or more elements joined up and formed in chemical reactions.
What does a chemical reaction involve?
A chemical reaction involves chemicals (called the reactants) combining together or splitting apart to form one or more new substances (called the products).
When do elements combine?
When a new compound is synthesised (made).
How are the new compounds produced by a chemical reaction different from the original elements (or reactants)?
The new compounds produced by any chemical reaction are always completely different from the original elements (or reactants).
What is a chemical change and what are examples?
A chemical change is an irreversible reaction involving the formation of new substances. An example is wood burning.
How can you observe that a chemical reaction has taken place?
You can observe that a chemical reaction has taken place in these ways:
- New substances formed
- Reactants used up
- Effervescence (bubbles)
- Heat/light/sound
- Electricity produced
- A precipitate (solid) formed
What is an example of a word equation using iron and sulfur naming the reactants and products?
iron + sulfur ==> iron sulfide
REACTANTS ==> PRODUCTS
What is the ending when two different elements combine?
When two different elements combine the ending is usually “something-ide”.
Sulfur changes to Sulfide
Iodine changes to Iodide
What is the ending when three or more different elements combine and one of them is oxygen?
When three or more different elements combine - and one of them is oxygen - the ending will usually be “something -ate”.
