Module 2.1 - Atoms and Reactions

Question 1

What is an empirical formula?

Answer 1

The simplest way of showing a chemical formula, shows the ratio between elements, rather than actual numbers of atoms of each element.

Question 2

What is a molecular formula?

Answer 2

Tells you the number of each type of atom that make up a molecule.

Question 3

What is Avogadro’s constant?

Answer 3

6.02 x 10^23

Question 4

What is the equation for moles?

Answer 4

number of moles = mass / molar mass

Question 5

How many outer electrons do atoms in Group 2 have?

Answer 5

2

Question 6

Finish the equation pressure x volume (pV)?

Answer 6

pressure x volume = moles (mol) x gas constant (8.314) x temperature (K)

Question 7

What is the equation for concentration?

Answer 7

concentration = moles / volume

Question 8

What is the equation to find the volume of a gas at room temperature and pressure?

Answer 8

volume = moles x 24

Question 9

What is the equation to find the number of particles?

Answer 9

Number of particles = moles x Avogadro’s constant.

Question 10

What is the molecular formula for nitrate?

Answer 10

NO3^-

Question 11

What is the molecular formula for a carbonate?

Answer 11

CO3^2-

Question 12

metal + acid ->

Answer 12

metal + acid -> metal salt + hydrogen

Question 13

metal oxide + acid ->

Answer 13

metal oxide + acid -> salt + water

Question 14

metal hydroxide + acid ->

Answer 14

metal hydroxide + acid -> salt + water

Question 15

metal carbonate + acid ->

Answer 15

metal carbonate + acid -> metal salt + carbon dioxide + water

Question 16

ammonia + acid ->

Answer 16

ammonia + acid -> ammonium salts.

Question 17

What is a standard solution?

Answer 17

A solution that has a precisely known concentration.

Question 18

What is the equation of percentage yield?

Answer 18

percentage yield = (actual yield / theoretical yield) x 100

Question 19

What is the equation for atom economy?

Answer 19

atom economy = (molecular mass of desired product / sum of molecular masses of all products) x 100

Question 20

What is atom economy?

Answer 20

Atom economy is a measure of the proportion of reactant atoms that become part of the desired product (rather than by-products) in the balanced chemical equation.

Question 21

What is percentage yield?

Answer 21

Tells you how wasteful the process is and is based on how much of the product is lost because of things like reactions not completing or losses during collection and purification.

Question 22

Why is a high atom economy in reactions important for companies and their sustainability?

Answer 22

> Low atom economy means lots of waste being produced and it costs money to separate the desired product from the waste and to dispose of the waste products safely so that they do not harm the environment.
Reactant chemicals are usually costly, if they end up as useless products.
Reaction conditions with high energy demands cost a lot to maintain.

Question 23

What is the simple definition of oxidation?

Answer 23

Oxidation is a gain of oxygen and a loss of electrons.

Question 24

What is the simple definition of reduction?

Answer 24

Reduction is a loss of oxygens and the gain of electrons.

Question 25

What is the oxidation number?

Answer 25

The charge the atom would have if it was composed of ions, reflects the number of electrons that have been lost/gained.

Question 26

What oxidation number will an uncombined element have?

Answer 26

0

Question 27

What oxidation number will a combined oxygen have?

Answer 27

-2

Question 28

What oxidation number will a combined oxygen in peroxides have?

Answer 28

-1

Question 29

What oxidation number will a combined hydrogen have?

Answer 29

+1

Question 30

What oxidation number will combined hydrogen in metal hydrides have?

Answer 30

-1

Question 31

What are the 2 rules of oxidation numbers in formulae for compounds?

Answer 31

>Overall charge on the compound is 0. | >The sum of the oxidation numbers of the atoms must equal 0.

Question 32

What is the rule for oxidation numbers in formulae for molecular ions?

Answer 32

>The sum of the oxidation numbers of the atom must equal the overall charge on the ion.

Question 33

How do we represent the oxidation state of an element?

Answer 33

Roman numerals are used to represent the oxidation state of an element.

Question 34

What is a redox reaction?

Answer 34

A reaction where both oxidation and reduction is occurring.

Question 35

What happens in a redox reaction with metals and acids?

Answer 35

The metal is oxidised and the hydrogen (in the acid) is reduced to form hydrogen gas.

Question 36

What is the gas constant?

Answer 36

8.314

Question 37

What is the molecular formula for a sulphate ion?

Answer 37

SO4^2-

Question 38

What is the molecular formula for a hydroxide ion?

Answer 38

OH^-

Question 39

What is the molecular formula for a ammonium ion?

Answer 39

NH4^+

Question 40

What is the molecular formula for a zinc ion?

Answer 40

Zn^2+

Question 41

What is the molecular formula for a silver ion?

Answer 41

Ag^+