Addition Exam Prep

Question 1

Acid + Metal Hydroxide

Answer 1

Salt + water

Question 2

Acid + Metal Oxide

Answer 2

Salt + water

Question 3

Acid + Metal Carbonate

Answer 3

Salt + water + carbon dioxide

Question 4

Acid + Metal hydrogen carbonate

Answer 4

Salt + water + carbon dioxide

Question 5

Metal + acid

Answer 5

Salt + hydrogen

Question 6

Metal + Oxygen

Answer 6

Metal Oxide

Question 7

How can the strength of dispersion forces increase

Answer 7

Increase in size - strength increases as no. of electrons increases, resulting in increased strength of dispersion because net charges of dipoles.
Increase in surface area - increased branching of molecules results in increased surface area of interaction between molecules, hence stronger strength of dispersionb

Question 8

Pure substances

Answer 8

Have a fixed/constant composition and well-defined and constant physical and chemical properties

Question 9

Mixtures

Answer 9

Contain 2 or more different substances in varying ratios and can be separated using physical properties.

Question 10

Homogenous

Answer 10

Uniform composition throughout

Question 11

Heterogenous

Answer 11

Non uniform composition

Question 12

Dilution

Answer 12

C1V1 = C2V2

Question 13

Sieving

Answer 13

Separates components in a mixture based of particle size. Passed through sieve of suitable mesh to concentrate desired comppnent

Question 14

Decantation

Answer 14

Decantation is the process of separation of liquid from solid and other immiscible (non-mixing) liquids, by removing the liquid layer at the top from the layer of solid or liquid below.
Uses density

Question 15

Separating funnel

Answer 15

A separating funnel is used to separate two immiscible liquids based on their densities. The mixture is placed in the funnel, allowed to settle into two layers, and the denser liquid is drained off from the bottom. This method is commonly used to separate oil from water.

Question 16

Explain the cathode ray tube

Answer 16

Applying an electric field across the cathode ray caused the ray to be deflected towards the positive pole proving that cathode rays were composed of negatively charged particles and that they have a high mass to charge ratio.

Question 17

Rutherfords Gold Foil Experiment

Answer 17

Based on alpha particle scattering after striking a thin foil. This leads to the compulsion that most of the atom is empty space or space occupied by electrons, and that the nucleus is the source of mass.

Question 18

Multiple lines in hydrogens emission spectrum.

Answer 18

Observed multiple spectral lines for hydrogen atom even though it has only one electron. The lines are due to the electrons making transition between energy levels. Certain orbits/ energy levels are available.

Question 19

Chromatography

Answer 19

Series of analytical techniques used to separate mixtures of compounds for further use of analysis

Question 20

Paper Chromatography

Answer 20

Stationary Phase - paper (polar)

Question 21

Stationary Phase

Answer 21

Does not move, and compounds are attracted to it

Question 22

Mobile Phase

Answer 22

More soluble compounds are carried faster as mobile phase moves

Question 23

Adsorption

Answer 23

Slowing due to intermolecular forces w/ stationary phase

Question 24

desorption

Answer 24

attraction to solvent stronger that attraction to stationary phases

Question 25

TLC

Answer 25

stationary phase is polar silica gel.

Capillary action draws solvent up matrix –> dependent on solubility or charge, due to the interaction of solute and matrix.

Dry sample placed in matrix and solvent moves up and dissolves sample

Question 26

Rf

Answer 26

da/ds

distance travelled by a/distance travelled by solvent

Question 27

Advantages of TLC

Answer 27

Plate is rigid, therefore easier to controll
Reusable - scrape of gel, put in solvent, filter, reuse gel

Question 28

Gas chromatography

Answer 28

mobile phase - intert gas under pressure
stationary phase - liquid
sample must by gaseous

Question 29

HPLC

Answer 29

mp - liquid
sp - silica

Question 30

Explain why water has high surface tension

Answer 30

Surface tension is the tendency of a liquid to resist any increase in its surface area. Water has high surface tension due to its strong intermolecular forces. At the water surface, there is an imbalance of forces causing surface molecules to be pulling inwards towards the bulk of the liquid. As a consequence the surface is trying to contract and achieve minimum surface area.