U4 - Topic One Flashcards
What is the definition of a suspension?
A heterogeneous mixture of a solid in a liquid
What is the definition of a solution?
A homogeneous mixture of a solid or gas in a liquid
What is the definition of an emulsion?
A heterogeneous mixture of two or more liquids
What is the definition of a mist?
Minute droplets of a liquid in a gas
What is the definition of a smoke?
Minute droplets of a solid in a gas
What is the definition of an alloy?
A mixture of two or more metals or metals and non-metals
What is the definition of a gel?
A heterogeneous mixture of a liquid within a solid
What is the definition of a meringue?
A heterogeneous mixture of a gas within a solid
What is the definition of a foam?
A mass of small bubbles of gas in a liquid
What is homogeneous?
A mixture which has uniform composition and properties throughout
What is heterogeneous?
A mixture that does not have uniform composition and properties throughout
Name three ways you can coma or a compound of two substances and a mixture of the two substances
1) By appearance
2) If it’s magnetic
3) By heat (how it reacts etc)
Name three ways you can coma or a compound of two substances and a mixture of the two substances
1) By appearance
2) If it’s magnetic
3) By heat (how it reacts etc)
In what state does diffusion take place easiest and why?
Diffusion is faster in gases than it is in liquids and solids, as the molecules are further apart and are moving more quickly
What happens to the ink connected to a porous pot when hydrogen is outside the porous pot while air inside it?
The hydrogen diffuses into the pot faster than air diffuses out, causing an increase in pressure in the pot. This extra pressure pushes the ink away from the pot
How can you work out if a gas diffuses faster than another gas?
Gases with lower densities diffuse faster than gases with higher densities.
To work out which is lower, you need to work out the Mr (relative molecular mass) by looking at the top-left corner of the elements box in the periodic table and times it by however many atoms there are.
If a less dense gas is in a porous pot with a tube dipped in a beaker of water while a more dense gas is outside the pot, what happens to the water?
The gas in the pot would diffuse out of the pot quicker than the second would diffuse into the pot, making a partial vacuum in the porous pot. The water would rise (up the tube) to fill the vacuum
What’s Graham’s Law of Diffusion?
The square root of the Mr of one gas divided by the Mr of another
What kind of mixtures can be separated using a separating funnel?
Immiscible liquids (liquids which don’t mix together) with different densities
What is the process of centrifuging (and then decanting)?
Spinning a mixture of a liquid and insoluble solid very quickly in a test tube so the denser solid is thrown to the bottom of the test tube and the liquid is left on the top. The liquid can then be decanted (poured off) the solid
Why is a fluted filter paper more effective than a normal piece of filter paper?
The fluted filter paper has more surface area, so it filters faster
What’s the alternative to centrifuging and decanting?
Filtration
What precaution should you take when using a solvent that’s highly flammable?
Keep away from Bunsen burners, but if you do need to heat it, use an electric heater or a hot water bath
What precaution should you take if you are dealing with something that has harmful vapours?
Put it in the fume cupboard, do the experiment in the fume cupboard
What the chemical test for water?
Use anhydrous copper sulfate; it goes from white to blue
What’s the solvent and what’s the solute?
The solvent is the substance that something is dissolved into, and the solute is the substance that gets dissolved
