c8 chemical analysis

In chemistry what is a "pure" substance?

• A substance that has had nothing added to it and is in its "natural" state

• A substance made of a single element or compound

• A complex mixture designed as a useful product

• fuels, cleaning agents, paints, medicines, alloys, fertilisers and foods.

How can pure substances be distinguished from impure ones?

• By their melting/boiling points

• By their colour

• By their reaction with oxygen

• Whether they conduct or not

What is a formulation?

• A substance that has had nothing added to it and is in its "natural" state

• A substance made of a single element or compound

• A complex mixture designed as a useful product

• fuels, cleaning agents, paints, medicines, alloys, fertilisers and foods.

Which is NOT an example of a formulations

• fuels

• cleaning agents

• paints

• hydrogen gas

What is chromatography?

• A process to separate the constituents of a mixture

• A way to separate two liquids

• A process to separate solid from liquid

• A process which separates a soluble solid from a solvent

In paper chromatography, what is the stationary phase?

• The paper

• The solvent

• The mixture

• The chromatography jar

In paper chromatography, what is the mobile phase?

• The paper

• The solvent

• The mixture

• The chromatography jar

How is the Rf value calculated?

• distance moved by spot/distance moved by solvent

• distance moved by spot - distance moved by solvent

• distance moved by spot + distance moved by solvent

• distance moved by spot x distance moved by solvent

How can hydrogen be tested for?

• Makes a squeaky pop when a splint is placed in it

• Relights a glowing splint

• Bubble through limewater, turns it milky (cloudy)

• Bleaches damp litmus paper white

How can oxygen be tested for?

• Makes a squeaky pop when a splint is placed in it

• Relights a glowing splint

• Bubble through limewater, turns it milky (cloudy)

• Bleaches damp litmus paper white