amount of substance

Question 1

State Avogardo’s Law

Answer 1

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

Question 2

What are the benefits for sustainability of developing chemical processes with a high atom economy?

Answer 2

1. Less waste product produced, therefore less waste product is needed to be disposed of in the environment
2. Lower energy demands for reaction conditions are cheaper to run and better for the environment
3. Non-renewable sources are better for the environment

Question 3

How do you rearrange the ideal gas equation to work out temperature

Answer 3

T = PV / nR

Question 4

What does atom economy tell us?

Answer 4

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

Question 5

What are the ideal ways in which gases behave?

Answer 5

1. They are in continuous motion
2. No intermolecular forces experienced
3. Exert a pressure when they collide with each other or container
4. No kinetic energy is lost in the collisions
5. When temperature increases, kinetic energy of gases increases

Question 6

Which type of reaction has 100% atom economy?

Answer 6

Addition reactions

two or more reactants are combined to form a product

Question 7

Does 100% yield mean 100% atom economy and why?

Answer 7

• No
• Even if all reactants are converted into products, not all products of the reaction will be the desired product

Question 8

How do you rearrange the ideal gas equation to work out pressure

Answer 8

p = (nRT) / V

Question 9

How do you calculate the moles of a gas?

Answer 9

moles = volume (dm3) / 24

Question 10

How much volume does a gas occupy, at room temperature and pressure?

Answer 10

24dm3

Question 11

What is the equation to calculate solution volume?

Answer 11

volume = moles / concentration

Question 12

What does the Avogardo constant represent

Answer 12

The number of atoms per mole of the carbon-12 isotope

Question 13

How do you rearrange the ideal gas equation to work out moles

Answer 13

n = PV / RT

Question 14

What are the units for the ideal gas equation

Answer 14

Pressure = Pa
Volume = m3
Gas constant = 8.314 J mol-1
Temperature = K

Question 15

What is the pressure and temperature at r.t.p?

Answer 15

Pressure = 100 kPa / 1atm
Temperature = 298 K / 25°C

Question 16

What is the unit used to measure amount of substance

Answer 16

moles

Question 17

1 atmospheric pressure (atm) is equal to how many pascal (Pa)?

Answer 17

1 atm = 101,325 Pa

Question 18

What is the symbol for amount of substance?

Answer 18

n

Question 19

What are the 4 common state symbols?

Answer 19

(s) = solid
(L) = liquid
(aq) = aqueous
(g) = gaseous

Question 20

How do you calculate the mass of 1 mole of the element?

Answer 20

mass = mol x mr

Question 21

0°C is equal to how much kelvin (K)?

Answer 21

273 K

Question 22

What does the concentration of a solution mean?

Answer 22

It is the amount of solute dissolved in 1 dm3 of solvent

Question 23

How do you rearrange the ideal gas equation to work out volume

Answer 23

V = (nRT) / P

Question 24

What is a substitution reaction?

Answer 24

A substitution reaction is one where some atoms from one reactant are swapped with atoms from another reactant - it forms at least two products.

Question 25

What do the terms concentrated and dilute mean?

Answer 25

Concentrated = large amount of solute per dm3 of solvent Dilute = small amount of solute per dm3 of solvent

Question 26

What does the percentage yield mean?

Answer 26

The efficiency of which reactants are converted into products

Question 27

What is a species in a chemical reaction?

Answer 27

Any particle that takes a part in a reaction

Question 28

What are the reasons for not obtaining 100% yield?

Answer 28

1. **Reaction may be at equilibrium** 2. The reactants may be **impure** 3. **Side reactions** could occur 4. Reactants or products may be **lost when transferring** 5. **Loss of products** during seperation and purification

Question 29

What is the ideal gas equation

Answer 29

pV = nRT

Question 30

How is atom economy calculated

Answer 30

(mr of desired product / sum of all the mr of all the products) x 100

Question 31

Why do different gas particles occupy the same volume?

Answer 31

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

Question 32

How is percentage yield calculated?

Answer 32

(actual amount of product / theoretical amount of product ) x 100

Question 33

What does a low atom economy mean and why is it not ideal?

Answer 33

- Low atom economy means there are waste products produces - It costs money to separate the desired product from the waste products and more money to dispose of the products safely - Less sustainable, many raw materials are in limited supply. Raw materials come from renewable sources and are better for the environment than materials from non-renewable sources.

Question 34

How do you convert moles into grams?

Answer 34

mass = moles x mr

Question 35

Define molar gas volume

Answer 35

The volume per mole of gas molecules

Question 36

How do you calculate moles when concentration and volume are given?

Answer 36

moles = concentration x volume

Question 37

What is a standard solution?

Answer 37

A solution of known concentration

Question 38

How do you calculate moles when mass and mr are given?

Answer 38

Moles = mass / mr

Question 39

What is the equation to calculate solution concentration?

Answer 39

concentration = moles / volume

Question 40

What is the theoretical yield?

Answer 40

Theoretical yield is the mass of product that should be made in a reaction if no chemicals are lost in the process

Question 41

Describe the steps taken to prepare a standard solution

Answer 41

1. Weigh the solute 2. In a beaker dissolve the solute using the solvent 3. Pour the solution into a volumetric flask 4. Rinse the beaker using the solution and add it to the flask 5. Add solvent to the flask carefully until it reaches the graduation line 6. Mix the solution thoroughly to ensure complete mixing

Question 42

How do you convert cm3 into m3

Answer 42

divide by 1 x 10^6

Question 43

How do you convert dm3 into m3

Answer 43

divide by 1000

Question 44

How do you convert °C into K

Answer 44

add 273

Question 45

How do you convert kPa into Pa

Answer 45

multiply by 1 x 10^6