Amount of Substance

Question 1

What does the avogadros constant represent

Answer 1

The number of atoms per mole of the carbon 12 isotope

Question 2

How do you Calculate the mass of 1 mole of an element

Answer 2

mass of 1 mole= RAM in grams

Question 3

How do you calculate moles when mass and molar mass are given

Answer 3

Moles(Mol)= Mass(g) / Molar mass (g mol^-1)

Question 4

What is avogradros law

Answer 4

Under the same temp and pressure one mole of any gas would occupy the same volume

Question 5

How much volume does a gas occupy at room temp and pressure

Answer 5

24dm^3 or 24,000 cm^3

Question 6

Define molar gas volume

Answer 6

The volume per mole of gas molecules

Question 7

Why do different particles occupy the same volume

Answer 7

The gas particles are very spread out hence individual differences has no effect

Question 8

How do you calculate moles when gas volume is given?

Answer 8

Moles= volume (dm3) / 24
or
Moles= volume (cm3) / 24000

Question 9

What are the ideal way in which gases behave (5)

Answer 9

They are in continuous motion
No intermolecular forces are experinced
Exert pressure when they collide with each other or the container
No kinetic energy is lost in the collisions
When temperature increases the kinetic energy also increases

Question 10

What is the ideal gas equation

Answer 10

PV=NRT
Pascals x volume (m^3)= Number of moles x gas constant (8.314) x Temperature (kelvin)

Question 11

How much is 1 atmospheric pressure equal to in pascals

Answer 11

101325 pascals

Question 12

0 degrees celcius is equivalent to how many kelvins

Answer 12

273 kelvin

Question 13

What does concentration of a solution mean

Answer 13

It is the amount of solute dissolved in 1 dm^3 of solvent

Question 14

How do you calculate moles when conc and vol are given

Answer 14

moles = conc x vol

Question 15

What is a standard solution

Answer 15

A solution of known conc

Question 16

What does the term concentration mean

Answer 16

large amount of solute per dm^3

Question 17

What does the term dilute mean

Answer 17

small amount of solute per dm^3

Question 18

What is a species in a chemical reaction

Answer 18

any particle that takes part in the reaction

Question 19

What are the 4 common state symbols

Answer 19

Gas(g)
Liquid(l)
Solid(s)
Aqueous (aq)

Question 20

What does percentage yield mean

Answer 20

The efficient of which reactants are converted into products

Question 21

What are the reasons for not obtaining 100% percebtage yie;d

Answer 21

Reaction may be at equilibrium
The reactants may be impure
Side reactions could happen
Reactants or products may be left behind while transferring
Loss of products during separation and purifciation

Question 22

How is pervenatge yield calculated

Answer 22

Percentage yield=Actual amount of product/ theortical amount of product x100

Question 23

What does atom economy tell you

Answer 23

The proportion of desired products compared with all the products formed with the reaction

Question 24

How is atom economy calculated

Answer 24

Atom economy= Molecular mass of desired product/sum of the molecular masses of all products x 100

Question 25

How do you know when relative formula mass is used

Answer 25

Mr( relative formula mass) is used for ionic compounds becaus ethey dont exist as molecules

Question 26

Equation for number of moles

Answer 26

Number of moles=Mass/Mr

Question 27

Define solution

Answer 27

A solution consists of a solvent with a solute dissolved in it

Question 28

Formula for conc

Answer 28

Conc(moldm^3)=Number of moles/Volume(dm^3)

Question 29

How many decimetres are there in 1000cm^3

Answer 29

1dm^3

Question 30

Formula for number of moles in a solution

Answer 30

Conc(dm^3)x Vol(cm^3)/1000