C3.1 Chemical Reactions

Question 1

What is the formula for metal elements always written as?

Answer 1

Empirical because they exist as giant lattices

Question 2

What group exists as diatomic molecules?

Answer 2

Group 7(covalently bonded)

Question 3

Which other elements exist as diatomic?

Answer 3

Hydrogen, nitrogen, oxygen

Question 4

Which other elements exists as weird molecules?

Answer 4

Sulphur(S4)

Phosphorus (P4)

Question 5

Stage the orders of charges of groups

Answer 5

+1,+2,+3,-4,-3,-2,-1,0

Question 6

What is each row in the periodic table and what does it determine?

Answer 6

Period, number of electron shells

Question 7

What is each column in the periodic table called and what do they have in common

Answer 7

Group, electrons in the outer shell

Question 8

What charge does a hydrogen ion have?

Answer 8

H+

Question 9

Ammonium ion

Answer 9

NH4+

Question 10

Carbonate ion

Answer 10

Co3 ^2-

Question 11

Sulfate ion

Answer 11

So4 ^2-

Question 12

Hydroxide and nitrate ion

Answer 12

OH-, NO3-

Question 13

What is the law of conservation of mass?

Answer 13

Atoms cannot be created or destroyed in chemical reactions, they are just joined in different ways

Question 14

Describe an experiment you can use to show that mass is conserved

Answer 14

Carry out a reaction in a closed system where nothing can leave or enter. Measure the reactants before and after they react

Question 15

Why does mass sometimes change?

Answer 15

Some products can leave if it is a non enclosed system, probably gases

Question 16

Why does mass sometimes go up in reactions?

Answer 16

When a metal reacts with oxygen it produces a metal oxide where the oxygen atoms add mass

Question 17

What is a half equation?

Answer 17

A model for the change that happens to one reactant in a chemical reaction. You are usually asked to write 2 or more

Question 18

What must your remember to do when writing half equations?

Answer 18

Write the charges of the ions on both sides
Ignore the big number such as the 2 in 2Na
Don’t ignore the subscript numbers
Never write something to lose electrons
Balance using only big numbers
State symbols

Question 19

What is an ionic equation?

Answer 19

An equation which only shows the ions present in a reaction mixture without spectator ions

Question 20

What is a precipitate?

Answer 20

A solid formed in a reaction of liquids

Question 21

What is a mole?

Answer 21

The amount of any substance which contains the same number of entities as there are atoms in 12g of carbon 12

Question 22

How many atoms does one mole have?

Answer 22

6.02x10^23

Avagadros constant

Question 23

What is avagadros constant?

Answer 23

The number of entities in one mole

Question 24

Formula for moles and mass

Answer 24

Moles(mol)= mass(g) / molar mass(g/mol)

Question 25

What is a limiting reactant?

Answer 25

What determines the amount of final product formed and runs out the quickest