Stoic

Question 1

Pure substance

Answer 1

matter is anything that takes up space

Question 2

Elements

Answer 2

atoms all having the same numbers of protons

Question 3

Molecules

Answer 3

two or more elements chemically joined together

Question 4

Compounds

Answer 4

Two or more different elements chemically joined together in a fixed ratio

Question 5

Mixtures

Answer 5

a combinations of pure substances

Question 6

aqueous

Answer 6

dissolved in a solvent

Question 7

physical change

Answer 7

no new substances are produced

Question 8

Chemical change

Answer 8

new chemical substance are formed

Question 9

mole

Answer 9

the amount of substances that contains the same number of specified particles as there are atoms in 12g of carbon-12

Question 10

mole symbol

Answer 10

n

Question 11

avogardos number

Answer 11

6.02 x 10 to the power of 23

Question 12

relative atomic mass

Answer 12

the average mass of all isotopes of an element compared to 1/12 the mass of carbon 12 atom

Question 13

relative formal mass

Answer 13

the mass of a molecule compared to 1/12 the mass of C-12 atom

Question 14

number of moles

Answer 14

n = m/M

Question 15

percentage composition

Answer 15

%composition by mass of element = molar mass of x/ molar mass of the compound

Question 16

Empirical formula

Answer 16

the formula of a compounds that shows the lowest whole number ratio of each type of atom

Question 17

Step to calculate EF

Answer 17

1. Write the elements present in the compound
2. Write each elements % composition or mass
3. divide the % or mass by the relative atomic mass and calculate the ratio
4. divide each ratio by the smallest ratio above to get a whole number ratio
5. express as empirical formula

Question 18

molecular formula

Answer 18

the formula of a compound that shows the actual number of each type of atom in the molecule

Question 19

Atom economy

Answer 19

chemical reaction is a measure of the amount of starting material that become useful products

Question 20

calculate atom economy

Answer 20

atom economy = total mass of desired products/ total mass of all products or reductants x100

Question 21

Limiting Reactant

Answer 21

reactant that will be used up first in a chemical reaction

Question 22

how to determine limiting reactant

Answer 22

divide the moles by the leading co-efficient

Question 23

Percentage yield equation

Answer 23

percentage yield(%)= actual yield/ theoretical yield x100

Question 24

percentage yield

Answer 24

amount of product produced experimentally compared to the theoretical waver.

Question 25

Theory of an ideal gas

Answer 25

- gaseous particles are in continuous random motion, in straight lines not curved. - perfect elastic Collison - average kinetic energy is directly proportional to temperature - volume of gas is negligible -no intermolecular forces

Question 26

Ideal gas equation

Answer 26

PV=nRT

Question 27

universal gas constant

Answer 27

8.31

Question 28

charles law

Answer 28

V/T=k

Question 29

boyles law

Answer 29

PV=k

Question 30

real gases

Answer 30

- gas particles have volumes - particles have attractive forces

Question 31

Ideal Gases

Answer 31

- gas particles do not have volume - no attractive forces between particles

Question 32

gas behaviour

Answer 32

a gas behaves more ideal at a high temperature and lower pressure higher temperature: the potential energy due to intermolecular forces become less significant compared with the particles kinetic energy Low Pressure: the size of molecules become less significant compared to the empty space between them

Question 33

Molar volume

Answer 33

the volume occupied by one mole of a substance at a given tempature and pressure

Question 34

STP

Answer 34

273K and 100kPa

Question 35

Vm at STP

Answer 35

22.7dm3

Question 36

solute

Answer 36

the smallest component in a solution

Question 37

solvent

Answer 37

the largest component of a solution

Question 38

Solution

Answer 38

the solute and solvent combinded

Question 39

Concentration

Answer 39

a measure of solute

Question 40

concentration equation

Answer 40

concentration = mole of solute/ volume of solution c=n/v

Question 41

dilution

Answer 41

the process of adding more solvent to a solution

Question 42

dilution formula

Answer 42

C1V1=C2V2