Chapter 13- Water The Universal Solvent

Question 1

Aqueous solution

Answer 1

Is formed when

• a solid, liquid or gas
• is dissolved in water.
• when two aqueous reactants are combined in a reaction vessel, he dissolved reactant particles mix freely. This increases the chances of the reactants coming into contact. Because of the increased movement of the reactant particles, interactions between reactants are generally more effective than if the same reactants were mixed as solids.

Question 2

Solute

Answer 2

The substance being dissolved

Question 3

Solvent

Answer 3

The liquid in which the substance is dissolved

• the solute of an aqueous solution can change, but the solvent will always be water.

Question 4

All solutions have the following (3) characteristics

Answer 4

1) the solute and the solvent cannot be distinguished from each other (solution is homogenous)
2) dissolved particles are too small to see
3) amount of dissolved solute can vary from one solution to another

Question 5

Homogenous solutions

Answer 5

The solute and solvent particles cannot be distinguished from each other. Every part of the solution is the same as the other part.

Question 6

Dissolution

Answer 6

Process of a substance dissolving in another substance

Question 7

Miscible

Answer 7

When the two substance dissolving in another substance are both liquid.

Question 8

The process of dissolution

3

Answer 8

• the particles of the solute are separated from one another
• the particles of the solvent are separated from one another
• the solute and solvent particles are attar ted to each other.
• for a solution to form. The solute molecules must interact with the solvent molecules. The solute particles are surrounded by solvent molecules and carried throughout the solution.

Question 9

The 3 forces involved in how a substance will dissolve in water.

Answer 9

• holding the particles of the solute together before it is added to the solvent
• holding the solvent molecules together. (In water these forces are hydrogen bonds)
• forces that can form between solute particles and solvent molecules of the substance dissolves
• for substances to dissolve the attractive forces that form between the solute and solvent particles must be sufficient to overcome the forces between the in the solute and the forces between the molecules in the solvent.

Question 10

For a substance to be soluble ….

Answer 10

The solute-solvent interactions must be stronger than the solute-solute and solvent-solvent interactions

Question 11

How to predict whether a substance is likely to dissolve una other substance.

Answer 11

‘Like dissolves Like’ rule

• polar-polar
• non polar-non polar

Question 12

Importance of water’s solvent properties is evident in which three contexts

Answer 12

• biological
• domestic
• industrial

Question 13

Biological contexts

Answer 13

• involves living things
• human body 66% water by weight
• water provides systems of transport nutrients and soluble wastes
• also transports essential reagents for chemical reactions to cells and tissues
• circulatory system
• transport system in plants
• cyclists

Question 14

Domestic contexts

Answer 14

• saline solution: solution of sodium chloride is used for cleaning and storing contact lenses
• soft drink: solution of sugar, colour, flavour and carbon dioxide in water
• pasta: salt dissolve in boiling water
• water biased paint

Question 15

Industrial context

Answer 15

• processing of raw materials and manufactures of products of factories
• water- soluble medications : aspirin
• water soluble fertilisers

Question 16

What happens when a polar molecular substance dissolves in water by forming hydrogen bonds?

Answer 16

The equation for dissolution places water (h20) above the arrow.
H2O

C2H5OH(l)———>C2H5OH(aq)

Question 17

What happens when hydrogen chloride dissolves in water?

Answer 17

• polar covalent bonds within hydrogen chloride molecules break, producing hydrogen ions (H+) and chloride ions (C-)
• a covalent bond forms between each H+ and an H2O molecule forming H3O+ ions
• ion-dipole attraction form between the H3O+ and Cl- ions and polar water molecules

Question 18

ion-dipole attraction

Answer 18

Attraction between an ion and polar molecule such as water

Question 19

Hydrated

Answer 19

When a molecule is surrounded by water molecules

Question 20

Dissociation

Answer 20

Process of

• separating positive and negative ions
• from a solid ionic compound
• to form: hydrated ions when an ionic compound dissolves in water

Question 21

What happens when sodium chloride dissolves in water?

3

Answer 21

• ionic bonds within the sodium chloride lattice are broken
• hydrogen bonds between water molecules are broken
• ion-dipole attractions form between ions and polar water molecules.

Question 22

What is the SNAPE ruled used for

Answer 22

A handy way to remember many of the soluble salts in which he initials SNAPE

Question 23

What does SNAPE stand for?

Answer 23

• salts that contain one or more of the following ions are soluble
• SODIUM (Na+)
• NITRATE (NO3-)
• AMMONIUM (NH4+)
• POTASSIUM (K+)
• ETHANOATE (CH3COO-)

Question 24

Precipitation reaction

Answer 24

Issues if ions in solution combine to form a new compound that is insoluble in water.

Question 25

Precipitate

Answer 25

Insoluble compound formed in a precipitation reaction

Question 26

Spectator ions

Answer 26

Because the ions have not been involved in forming a precipitate .