Unit 4 Glossary

Question 1

Define accuracy

Answer 1

A measure of the agreement between a measurement and the true or correct value

Question 2

Define actual yield

Answer 2

The quantity of a product that is obtained from a chemical reaction

Question 3

Define anomalous data

Answer 3

Data with unexpected values that do not match the relationship observed in previous measurements

Question 4

Define atom economy

Answer 4

A ratio of the total mass of atoms in the desired product to the total mass of atoms in the reactants

Question 5

What is a back titration

Answer 5

A titration pre-formed when an insoluble and so reacting reagent is treated with an excess of an acid or base

Question 6

Define chromatography

Answer 6

Attend technique for analysing or separating mixtures of gases liquids or dissolved substances based on differential solubility in two phases

Question 7

What is a colorimeter

Answer 7

An instrument used to measure the intensity of colour in a solution

Question 8

Define concentration

Answer 8

The ratio of amount of a substance dissolves in a given volume of solution

Question 9

What is a dependent variable

Answer 9

The variable that is measured during an investigation

Question 10

What is emission spectroscopy

Answer 10

The study of emission spectra produced by excited substances

Question 11

What is gravimetric analysis

Answer 11

A method of quantitive analysis for finding the Composition and formula of compound is based on an accurate weighing of reactants and products

Question 12

What is an independent variable

Answer 12

The variable that is manipulated or change during an investigation

Question 13

Define literature value

Answer 13

A value from the chemical literature or a physical constant or experimental measurement

Question 14

What is a mobile phase

Answer 14

Liquid or gas which personally through or along stationary phase during chromatography

Question 15

Define percentage error

Answer 15

And Erin expressed as a percentage of the value measured or the true value

Question 16

Define percentage uncertainty

Answer 16

Random uncertainty/actual measurement times 100

Question 17

Define percentage yield

Answer 17

The actual yield as a percentage of the theoretical yield

Question 18

Define precision

Answer 18

The total amount of random error present in a measurement indicates how close together a series of measurements are

Question 19

Define qualitative analysis

Answer 19

Analysis used to identify the substance but not the quantity of the substance

Question 20

Define quantitative analysis

Answer 20

Analysis used to determine the quantity of each component of the material or substance

Question 21

What is a redox reaction

Answer 21

Reaction involving reduction or oxidation which results in one or more electrons being transferred and is accompanied by changes in oxidation numbers

Question 22

What is a redox titration

Answer 22

A titration used to determine the concentration of a solution of an oxidising or reducing agent

Question 23

Define retention time

Answer 23

The time between injection of a substance into a chromatography column and the appearance of the peak

Question 24

What is a separating funnel

Answer 24

Fun over the top at the lower end of the stopper in the tool used to separate immiscible liquids

Question 25

What is solvent extraction

Answer 25

A method for separating a compound from a mixture by causing it to move to another solvent

Question 26

What is a standard solution

Answer 26

A solution his concentration is actually known and which does not change with time

Question 27

What is the stationary phase

Answer 27

One of the two faces forming a crow much to graphic system which may be solid jail or liquid

Question 28

What is steam distillation

Answer 28

A technique used to purify organic substances that are immiscible with water and which would decomposed if distilled

Question 29

Define systematic error

Answer 29

An error which bias is your measurements in some predictable way

Question 30

What is theoretical yield

Answer 30

The maximum amount of mass of a particular product that can be formed when the limiting reactant is completely consumed and there is no losses or side

Question 31

Define titration

Answer 31

A chemical technique in which one solution is used to analyse another solution and find its concentration or amount

Question 32

What is vacuum filtration

Answer 32

A mixture of solid and liquid is poor through a filter paper in Büchner funnel the solid is trapped by the filter and the liquid is drawn through the funnel into the flask bellow by a vacuum

Question 33

Define water of crystallisation

Answer 33

Water molecules contained in the crystal lattice of organic salts when Play crystallise from aqueos solution