Chemistry Lecture Notes Review

Flashcards from lecture notes on Chromatography, Acids and Bases, Reactions of Acids, Making Salts, and Solubility.

What are the two phases involved in chromatography?

Mobile phase and stationary phase

What is the mobile phase in chromatography?

The phase where molecules can move; it is always a liquid or a gas.

What is the stationary phase in chromatography?

The phase where molecules can't move; it can be a solid or a thick liquid.

What determines how fast a chemical moves through the stationary phase?

How it distributes itself between the mobile and stationary phases

What is the mobile phase in paper chromatography?

A solvent (e.g., water or ethanol)

What is the stationary phase in paper chromatography?

A piece of filter paper

What is the formula for calculating the Rf value in chromatography?

Rf = (distance traveled by solute) / (distance traveled by solvent)

What is a locating agent used for in chromatography?

Sprayed on the chromatogram to show where the spots are, especially for colorless chemicals like amino acids.

What does a purity test using chromatography reveal?

A pure substance will move as one blob, while a mixture will separate into multiple spots.

Define the term 'standard reference materials (SRMs)'?

Pure substances with controlled concentrations and purities, to check components' identities.

What is a simple method to determine the solvent contained in ink?

Simple distillation, assuming the solvent has the lowest boiling point.

During distillation, what does the thermometer measure?

The boiling point of the solvent as it evaporates.

What three processes are used to purify water?

Filtration, sedimentation, and chlorination

Why is deionised water used in experiments?

To avoid interference from ions present in tap water, which can cause false results.

What is the pH scale used for?

To measure how acidic or alkaline a solution is.

What type of ion do acids form in water?

H+ ions (hydrogen ions)

What type of ion do alkalis form in water?

OH- ions (hydroxide ions)

What is an indicator?

A dye that changes color depending on the pH of a solution.

What color is litmus in acidic solutions?

Red

What color is methyl orange in acidic solutions?

Red

What color is phenolphthalein in alkaline solutions?

Pink

What products are formed during a neutralization reaction?

Salt and water

Define a strong acid

Acids that ionize almost completely in water.

Define a weak acid

Acids that do not fully ionize in solution.

What does the concentration of an acid measure?

How much acid there is in a litre (1 dm³) of water.

What happens to the pH if the concentration of H+ ions increases by a factor of 10?

The pH decreases by 1.

What products are formed when an acid reacts with a metal oxide?

Salt and water

What products are formed when an acid reacts with a metal hydroxide?

Salt and water

What products are formed when an acid reacts with a metal?

Salt and hydrogen

How can you test for hydrogen gas?

Using a lighted splint, which will produce a 'squeaky pop'.

What products are formed when an acid reacts with a metal carbonate?

Salt, water, and carbon dioxide

How can you test for carbon dioxide gas?

By bubbling it through limewater, which will turn cloudy.

What is the main rule of solubility?

Soluble things dissolve in water and insoluble things don't.

What is a precipitation reaction used for?

To make a pure, dry sample of an insoluble salt.

Are common carbonates and hydroxides soluble or insoluble?

Insoluble (except for sodium, potassium, and ammonium ones)

Insoluble (except for sodium, potassium, and ammonium ones)

By heating the acid in a water bath, then adding the base until it is in excess, filtering off the excess solid, and crystallizing the salt.

What is a titration?

When you work out the exact right amount of alkali to neutralise the acid.