Chapter 3 & Chapter 4: Elements, Compounds and Mixtures, Solution and Suspensions and Separating Mixtures Flashcards
Define elements.
Elements are the basic building blocks of living and non-living matter. They cannot be broken down into simpler substances.
Define compounds.
They consist of 2 or more elements that are chemically combined together.
What are the characteristics of compounds?
They do not have the same properties as their constituent elements. The constituent elements of a compound are always chemically combined in a fixed proportion by mass. A compound cannot be separated into its constituent elements easily, it would need alot of energy to break it down.
Define mixture.
A mixture consists of two or more elements and/or compounds that are not chemically combined together
What are the characteristics of mixtures?
They have the same characteristics as their constituents. The constituents of a mixture can be separated easily and do not have a fixed proportion.
What is a solution?
A solution is a mixture in which one substance dissolves completely in another substance.
The substance that dissolves is called the ______
solute
The substance in which the solute dissolves in is called the ______
solvent
With a fixed volume of water, a solution with a low percentage of dissolved solute, it is known as a ___________. A solution with a high percentage of dissolved solute is known as ____________
dilute solution, concentrated solution
What is rate of dissolving?
It refers to how quickly the solute dissolves in a solvent.
What factors affect rate of dissolving?
Temperature of solvent, size of solute particles and rate of stirring.
What is solubility?
It refers to how well a solute dissolves in a fixed volume of a particular solvent.
What factors affect solubility?
Type of solute, type of solvent, temperature of solvent.
Define suspension.
It is a mixture that contains insoluble substances in a solvent.
What are the characteristics of a solution?
- Particles of the solute cannot be seen
- Solute does not settle to form solid deposits
3.Light can pass through fully - Cannot separate via filtration.
- Homogenous
What are the characteristics of a suspension?
- Insoluble substance can be seen
- Insoluble substances can settle to form solid deposits
- Light cannot pass through fully.
- Can separate via filtration.
- Heterogenous
What are the 6 ways a mixture can be separated into its constituents by physical methods?
- Magnetic attraction
- Filtration
- Evaporation
- Distillation
- Chromatography
- Separating funnel
What does magnetic attraction do?
It separates magnetic materials from non-magnetic materials
What is the liquid that can pass through the filter paper?
Filtrate
What is the solid that is left at the filter paper called?
Residue
What does filtration do?
It separates substances of different particle sizes
What does evaporation do?
It obtains a dissolved solid from a liquid
What is crystalisation used for?
For substances which will decompose
When can you use evaporation to dryness?
For substances which will not decompose
What is distillation used for?
To separate substances with different boiling points through boiling and condensation.
What is the liquid that distills over called?
Distillate
What are boiling chips for?
To ensure smooth boiling
Where should the thermometer be placed at?
At the mouth of the condenser to measure the boiling point of the liquid.
How does chromatography work?
Based on the solubility of the substance in a solvent.
Why must the starting line be drawn in pencil?
The pencil lead will not dissolve in the solvent and thus will not affect the results
What are separating funnels used for?
To separate immiscible liquids of different densities.
What is chromatography used for?
To separate small amounts of substances that dissolve to different extents in a particular solvent.
Why must the starting line be above the solvent level?
To prevent the sample on the starting line from dissolving directly into the solvent.
What are immiscible liquids?
Liquid that do not mix together
What is reverse osmosis used for?
To purify water through a partially permeable membrane to separate ions, unwanted molecules and larger particles.
What does a partially permeable membrane have?
Very small pores that only water to pass through.
How can you determine whether a substance is pure or impure?
- Measure its boiling point
- Chromatography
Are elements pure or impure?
Pure
How can you tell if a substance is pure or impure when you use boiling or melting?
Pure: Substance melts/ boils at a fixed temp
Impure: Substance melts/ boils over a range of temperature.
Are mixtures pure or impure?
Impure
Are compounds pure or impure?
Pure
