lec

Question 1

Make up the materials we encounter everyday.

Answer 1

atoms

Question 2

It is a particle of matter that uniquely defines a chemical element (TechTarget).

Answer 2

atoms

Question 3

They react in simple whole number ratios form compounds

Answer 3

atoms

Question 4

are composed of atoms of two or more elements.

Answer 4

compounds

Question 5

Its molar mass may be determined from the atomic masses of the component atomic elements and this molar mass of the compound is numerically equal to the molecular mass

Answer 5

compounds

Question 6

Commonly denoted as NA, is a SI defining constant with an exact value of 6.02214076x1023 reciprocal moles.

Answer 6

avogadro’s number

Question 7

It is used as a factor in the amount of substance in a sample, defined as the number of constituent particles divided by NA.

Answer 7

avogadro’s number

Question 8

The quantity of substance that contains the same number of ultimate particles (atoms, molecules, ions, etc.) as are contained in precisely 12.00 g of a particular isotope of carbon 12C.

Answer 8

mole

Question 9

molar mass of a compound

Answer 9

molecular mass in grams

Question 10

molar mass of an element

Answer 10

atomic mass in grams

Question 11

Avogadro’s number

Answer 11

N = 6.02 x 10^23 particles per mole

Question 12

Molar mass

Answer 12

grams/mole

Question 13

1 molecule of C6H12O6

Answer 13

6 atoms C, 12 atoms H, 6 atoms O

Question 14

1 mole of C6H12O6

Answer 14

6 moles C, 12 moles H, 6 moles O

Question 15

is a homogeneous mixture of two or more substances.

Answer 15

solution

Question 16

is the substance dissolved in a solvent and is usually present in smaller amount

Answer 16

solute

Question 17

is the dissolving medium

Answer 17

solvent

Question 18

components of a solution

Answer 18

solid, gas, liquid

Question 19

solute: gas
solvent: gas
solution: ?

Answer 19

gas (air)

Question 20

solute: gas
solvent: liquid
solution: ?

Answer 20

liquid (soda water, co2 in water)

Question 21

solute: liquid
solvent: liquid
solution: ?

Answer 21

liquid (ethanol in water)

Question 22

solute: gas
solvent: solid
solution: ?

Answer 22

solid (H2 in palladium)

Question 23

solute: solid
solvent: liquid
solution: ?

Answer 23

liquid (salt in water)

Question 24

solute: solid
solvent: solid
solution: ?

Answer 24

solid (bronze, brass, solder)

Question 25

contains the maximum amount of a solute that will dissolve in a given solvent at a specific temperature.

Answer 25

saturated solution

Question 26

contains less solute than it has the capacity to dissolve.

Answer 26

unsaturated solution

Question 27

contains more solute than is present in a saturated solution.

Answer 27

supersaturated solution

Question 28

is the ratio of the mass of a solute to the mass of the solution, multiplied by 100 percent.

Answer 28

percent by mass (%w/w)

Question 29

Is the percent by mass of each element in a compound

Answer 29

percent composition by mass

Question 30

is obtained by dividing the mass of each element in 1 mole of the compound by the molar mass of the compound and multiplying by 100 percent

Answer 30

percent composition by mass

Question 31

is the simplest whole number ratio of atoms present in a compound.

Answer 31

empirical formula

Question 32

a process in which a substance (or substances) is changed into one or more new substances

Answer 32

chemical reaction

Question 33

uses chemical symbols to show what happens during a chemical reaction

Answer 33

chemical equation

Question 34

the starting materials in chemical reaction

Answer 34

reactants

Question 35

the substance formed as a result of a chemical reaction

Answer 35

product

Question 36

diatomic elements

Answer 36

hydrogen (H), nitrogen (N), oxygen (O), fluorine (F), chlorine (Cl), bromine (Br), and iodine (I) tip: Cl I H F Br O N

Question 37

is the quantitative study of reactants and products in a chemical reaction.

Answer 37

stoichiometry

Question 38

is the reactant used up first in a reaction.

Answer 38

limiting reagent

Question 39

are the reactants present in quantities greater than necessary to react with the quantity of the limiting reagent

Answer 39

excess reagent

Question 40

the amount of product that would result if all the limiting reagent reacted.

Answer 40

theoretical yield

Question 41

the amount of product actually obtained from a reaction, is always less than the theoretical yield

Answer 41

actual yield

Question 42

describes the proportion of the actual yield to the theoretical yield is the measure of how efficient a given reaction is.

Answer 42

percent yield

Question 43

is one of the most important operations in a chemical analysis

Answer 43

sampling

Question 44

it is the most difficult step in the entire analytical process and the step that limits the accuracy of the procedure

Answer 44

sampling

Question 45

are used to identify chemical species, a qualitative analysis, from one that determines the amount of a constituent, a quantitative analysis

Answer 45

analytical methods

Question 46

is the representative portion of the bulk material.

Answer 46

sample

Question 47

the process by which a representative fraction is acquired.

Answer 47

sampling

Question 48

a substance or chemical constituent that is of interest in an analytical procedure.

Answer 48

analyte

Question 49

contains species that have chemical properties similar to the analyte.

Answer 49

sample matrix

Question 50

Such species can react with the same reagents as the analyte or they can cause an instrument response that cannot be easily distinguished from the analyte

Answer 50

sample matrix

Question 51

interference that is caused by extraneous species in the matrix.

Answer 51

matrix effects

Question 52

Such effects can be induced not just by the sample itself but also by the reagent and the solvent used to prepare the samples.

Answer 52

matrix effects

Question 53

macro analysis

Answer 53

>0.1 g

Question 54

semimicro analysis

Answer 54

0.01-0.1gg

Question 55

micro analysis

Answer 55

0.0001-0.01 g

Question 56

ultramicro analysis

Answer 56

< 0.0001 (10^-4) g

Question 57

major constituent

Answer 57

1%-100%

Question 58

minor constituent

Answer 58

0.01% (100 ppm) -1%

Question 59

trace constituent

Answer 59

1 ppb to 100 ppm

Question 60

ultratrace constituent

Answer 60

<1 ppb

Question 61

The items chosen for analysis are often called

Answer 61

sampling units, increments, gross sample

Question 62

steps in obtaining a representative sample

Answer 62

1) identify the population 2) collect a gross sample 3) reduce the gross sample to a lab sample

Question 63

is a device which detects or measures a physical property

Answer 63

sensor

Question 64

Sampling of metals and alloys is obtained by

Answer 64

sawing, milling, drilling

Question 65

can often then be produced by pouring the melt into distilled water.

Answer 65

granular sample