Atom and Moles

Question 1

The description and order of different representations of the atom.

Answer 1

1. Solid Sphere model: Just a solid sphere
2. Plum pudding model: Solid positive sphere with negative electrons within the sphere
3. Nuclear Model: Positive nucleus, negative electrons just around the nucleus
4. Planetary Model: Positive nucleus made of protons and neutrons, negative electrons in fixed energy levels (shells) around the nucleus
5. Quantum Model: Positive nucleus made of protons and neutrons, “clouds” of negative electrons around the nucleus in different energy levels

Question 2

Who made each representation of the atom?

Answer 2

Solid Sphere Model: John Dalton
Plum Pudding Model: J.J. Thompson
Nuclear Model: Ernest Rutherford
Planetary model: Niels Bohr
Quantum Model: Erwin Schrodinger

Question 3

What is an isotope?

Answer 3

An atom of an element with the same number of protons, but a different number of neutrons

Question 4

What is Relative Atomic Mass?

Answer 4

the mean mass of all the naturally occuring atoms in an element compared with the mass of 1/12 of carbon-12

Question 5

What is Relative Isotopic Mass?

Answer 5

the mean mass of an isotope compared with 1/12 of the mass of carbon-12

Question 6

What are the typical charges of each group on the Periodic Table?

Answer 6

Group 1: 1+
Group 2: 2+
Group 3: 3+
Group 4: no typical charge
Group 5: 3-
Group 6: 2-
Group 7: 1-
Group 0: 0

Question 7

What is Avagadro’s Constant?

Answer 7

The molecules/atoms in 1 mole of a substance

Question 8

What value is Avagadro’s Constant?

Answer 8

6.02*10²³

Question 9

What is the symbol for molar mass?

Answer 9

g mol⁻¹

Question 10

What is an emprical formula?

Answer 10

The simplest whole number ratio of atoms of each element in a compound

Question 11

What is a molecular formula?

Answer 11

the number and type of every atom in a molecule

Question 12

What is the concentration of a solution?

Answer 12

how many moles of a substance is dissolved in the volume of liquid it is in

Question 13

What is the symbol for concentration?

Answer 13

moldm⁻³

Question 14

How many cm³ are in 1 dm³?

Answer 14

1000cm³

Question 15

What value is the ideal gas constant?

Answer 15

8.314 J mol⁻¹ K⁻¹

Question 16

What is % yeild of a chemical reaction?

Answer 16

The percentage of the real yeild compared to the theoretical yeild

Question 17

What is the atom economy of a chemcial reaction?

Answer 17

The molar mass of the desired products compared to the total molar mass of all the products

Question 18

What is a hydrated salt?

Answer 18

Salt that contains water within its structure

Question 19

What is an anhydrous salt?

Answer 19

Salt that doesn’t contain any water within its structure

Question 20

What is water of crystalisation?

Answer 20

The water trapped within the crystal structure of a hydrated salt

Question 21

What is a standard solution?

Answer 21

A solution that has a known exact concentration

Question 22

What is a titration?

Answer 22

Adding a solution of known concentration to a solution of unknown concentration to determin the unknown solution’s concentration

Question 23

What is the formulae for the number of moles?

Answer 23

Moles = mass (g) /molar mass (g mol⁻¹)
Moles = number of particles / Avagadro’s constant

Question 24

What is the formula for the ideal gas equation?

Answer 24

pV = nRT
p = Pressure (Pa)
V = Volume = (m³)
n = number of moles (mol)
R = ideal gas constant (J mol⁻¹ K⁻¹)

Question 25

What is the formula for the concentration of a solution?

Answer 25

Concentration (mol dm⁻³) = moles (mol) / volume (dm³)

Question 26

What is the formula for the % yeild of a reaction?

Answer 26

% yeild = actual mass of products (g) / theoretical mass of products (g) * 100

Question 27

What is the formula for the % atom economy of a reaction?

Answer 27

% atom economy = molar mass of desired product (g mol⁻¹) / molar mass of total products (g mol⁻¹) * 100