Separation techniques
What separation technique separates insoluble solids from liquids in mixtures?
Hint: this technique is used with coffee beans and water to make coffee.
Filtering separates insoluble solids from liquids in mixtures.
What is a solution?
A solution is made up of a solute dissolved in a solvent. Seawater is a solution.
The formula for water is H2O. Is water a a mixture, compound or element?
Water is a compound.
What elements can be found in magnesium oxide?
Magnesium & Oxygen
Simon made popcorn. He heated oil in a cooking pot and put in the popcorn kernels. A minute later they popped to make popcorn. Is this a reversible or irreversible change? Explain why?
Irreversible change: A chemical reaction took place.
When some substances are heated, the changes cannot be reversed. Irreversible changes usually turn one substance into another. You cannot un-pop the popcorn.
To separate a soluble solid from a liquid (e.g. salt water), ______________ can be used.
The solution is heated so that the water __________ and leaves the dissolved solid behind.
What are the missing words?
Evaporation & evaporates
What is the difference between a solute and solvent?
The substance that dissolves, called the solute. The liquid in which the solute dissolves, called the solvent.
Example: salt is the the solute, water is the solvent.
How many different elements are in a molecule of water (H2O)?
Water: There are 2 elements in a molecule of water, Hydrogen & Oxygen.
What is the compound name for CO2? Use your Periodic table to help you.
Carbon dioxide
Does sugar dissolve more quickly in hot or cold water? Explain why.
Heating a solution makes solid solutes dissolve faster. This is because heat speeds up the particles and allows the solute to spread through the solution more easily.
Distillation has 3 steps. What are they?
1. Evaporating
2. Condensing
3. Collecting
What is the difference between mixtures and pure substances?
Mixtures are made up of particles of different substances. Pure substances consist only of particles of that substance. Most mixtures can be separated but pure substances cannot be separated.
What is the difference between an element and a compound?
An element is a pure substance containing only one kind of atom. A compound is a pure substance containing two of more kinds of atoms.
What is the element symbol for potassium?
K
Oxygen is an element found on the periodic table of elements. Oxygen is in the air and is what you breath into your body. Is air an element? Explain you answer.
Air is NOT an element it is a mixture. Oxygen is in the air we breath, however there are other particles mixed in the air as well, such as carbon dioxide.
In filtering, very small particles pass through tiny holes in the filter, but bigger particles cannot pass through. True or false?
True!
When doing the chromatography experiment in the lab, which substance was the solute and which substances what the solvent?
Water and Ink
Ink is the solute
Water is the solvent
Mixtures are two or more _____________ or ___________ NOT chemically combined.
Mixtures are two or more elements or compounds NOT chemically combined.
Write down the symbol for 3 non-metals.
Hint: Use your periodic table.
Example:
C - Carbon
Cl - Chlorine
He - Helium
What is capillary action?
Capillary action is the sticky attractive force between water molecules and the paper, which causes water to be soaked up.
Imagine that you have been stranded on a desert island. The only water you have available is seawater (saltwater). Explain in as much detail as possible how you could convert the saltwater to pure water. What separation technique will work best?
Distillation: Start by heating the saltwater solution. The water will start to evaporate and the liquid will turn into a gas. Then you need to cool the steam down and the steam condenses. The gas will then turn back into a liquid. Collect the pure water at the end.
____________ is the mixing of a solid with a liquid to make a solution.
Dissolving is the mixing of a solid with a liquid to make a solution.
Classify each of the following as an element, compound or mixture.
_ Dimond (C)
_ Air
_ Ammonia (NH3)
Element - Dimond (C)
Mixture - Air
Compound - Ammonia (NH3)
What is the compound name for NaCl?
Hint: Table salt
Sodium Chloride
At the beginning of this chemistry unit we saw magnesium heated until it burned with a very bright flame. A white powder was left behind after the reaction. What is the name of this white powder?
Magnesium oxide