2.1-2.3 Mixtures Solutions and Solvent (Experimental Techniques)

Rf value

Rf value

The ________ is a ratio and therefore has no units.

Impure liquid

________ is heated in a round bottom flask.

Shampoo

________ is a mixture of several chemicals and water.

Condenser

________ cools the steams to a pure liquid and it drops into the beaker.

Retention factor

________= distance moved by compound ÷ distance moved by solvent.

Volatile liquid

A(n) ________ is one that evaporated easily this is a sign that the forces between its particles are weak so ________ have low boiling points too.

mixture of gases

A(n) ________ condense on the beads in the fractional column.

Sugar

________ is the solute, water is the solvent.

Crystals

________ are collected by filtering the solution.

mixture of substances

It is also used to separate a(n) ________.

Filter paper

________ will only allow small liquid particles to pass through in the filtrate.

Pure substance

A(n) ________ has a definite, sharp, melting point and boiling point.

pure water

The vapour passes through the condenser, where it cools and condenses, turning into ________ which is collected in a beaker.

soluble solid usually

A(n) ________ gets more soluble as the temperature rises.

Solid particles

________ are too large to pass through the filter paper so will stay behind as a residue.

Lowest substance

The beads are heated to the boiling point of the ________, so that substance being removed can not condense on the beads.

Sugar

________ is more soluble in hot water than in cold water.

Filter paper

________ is placed in a filter funnel above another beaker.

Rf value

Calculating the ________ allows chemists to identify unknown substances because it can be compared with Rfvalues of known substances under the same conditions.

Solutions

When you mix sugar and water, the sugar seems to disappear

But there is one simple method you can use in the lab

You can check melting and boiling points

Example and procedure

Used to separate a dissolved solid from a solution, when the solid is more soluble in hot solvent than in cold (e.g

1

place a drop of black ink in the center of some filter paper

2

Now drop water onto the ink spot, one drop at a time

3

suppose there are three rings yellow, red

For water and ethanol

ethanol has a boiling point of 78 ºC and water of 100 ºC