Topic 5 Structures, Formulae And Equations

Question 1

What is a diatonic molecule?

Answer 1

Two atoms covalently bonded in a molecule. Some elements will only naturally exist as a diatonic molecule

Question 2

Examples of diatonic elements

Answer 2

Hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine

Question 3

Element

Answer 3

A substance that consists of only one type of atom and cannot be broken down into anything simpler. They are represented by atomic symbols

Question 4

Compound

Answer 4

A substance that consists of two or more (different) elements chemically combined. They are represented by formulae eg H2O

Question 5

How do you read chemical formula?

Answer 5

Symbols tell us the element/type of atom. Small numbers tell us how many of each element there is

Question 6

What do you do if there are brackets in a formula?

Answer 6

Multiply whatever’s in the brackets by the number given after them. If there isn’t a number just leave it

Question 7

Valency

Answer 7

The combining power of an atom or ion (the number of electrons the element needs to gain/lose to have a full outer shell)

Question 8

What does valency depend on?

Answer 8

What group the element is in in the periodic table

Question 9

How do you work out the chemical formula of compounds?

Answer 9

SVSDF. Symbols Valency Swap Divide Formula each element

Question 10

What does a compound containing a cation combined with a single non-metal end in?

Answer 10

-IDE

Question 11

What does the compound name end in if oxygen is present?

Answer 11

-ATE or -ITE

Question 12

What do chemical reactions use? (General name)

Answer 12

Reactants

Question 13

What do chemical reactions produce?

Answer 13

Products

Question 14

Acid + Metal =

Answer 14

Salt + Hydrogen

Question 15

Acid + Base =

Answer 15

Salt + Water

Question 16

Acid + Alkali =

Answer 16

Salt + Water

Question 17

Acid + Carbonate =

Answer 17

Salt + Water + Carbon Dioxide

Question 18

Acid + Hydrogencarbonate =

Answer 18

Salt + Water + Carbon Dioxide

Question 19

Acid + Ammonia =

Answer 19

Ammonium Salt

Question 20

What happens in atoms in chemical reactions?

Answer 20

No atoms are lost or made, but rearranged. As a result we can write balanced symbol equations showing the atoms involved

Question 21

How do you write balanced equations?

Answer 21

Step 1: write the word equation
Step 2: write the symbols and formulae needed
Step 3: balance the equation by making sure that the total number of each type of element is the same on both sides of the arrow. NEVER change the small number, only add numbers before the symbol/formula

Question 22

(s)

Answer 22

Solid

Question 23

(l)

Answer 23

Liquid

Question 24

(g)

Answer 24

Gas

Question 25

(aq)

Answer 25

Aqueous (dissolved) solution

Question 26

What are ionic equations?

Answer 26

Chemical equations in which species are written out as their dissociated ions

Question 27

What type of solutions do ionic equations occur in?

Answer 27

Aqueous

Question 28

What is an example of an ionic equation?

Answer 28

Neturalisation

Question 29

How do you write an ionic equation?

Answer 29

Step 1: write the word equation
Step 2: write the balanced symbol equation including state symbols
Step 3: split the ionic compounds into their individual elements, write them as ions!
Step 4: note the elements which are unchanged in going from reactants to products. These are spectator ions and aren’t involved in the reactions so can be removed
Step 5: rewrite the equation showing only the elements involved in the reaction.