Calderglen High School Formulae 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Calderglen High School

What is the CHEMICAL FORMULA of a substance? 1 What is the CHEMICAL FORMULA of a substance? answer The ratio of atoms of each element in the substance Calderglen High School

A group of atoms joined together by covalent bonds What is a molecule? 2 answer A group of atoms joined together by covalent bonds Calderglen High School

What is the molecular formula for this molecule? 3 answer C2H6O H H H C C O H H H Calderglen High School

What is the correct formula for this molecule? 4 answer H CHCl3 C Cl Cl Cl Calderglen High School

What is the chemical formula of hydrogen? 5 answer H2 Calderglen High School

How many atoms of each element are present in a molecule of H2O? 6 answer H = 2 O = 1 Calderglen High School

How many atoms of each element are present in a molecule of C6 H12O6? 7 answer C = 6 H = 12 O = 6 Calderglen High School

What is meant by the prefix:- Mono? 8 answer Mono = 1 ie carbon monoxide molecules contain one oxygen atom (CO) Calderglen High School

What is meant by the prefix:- Di? 9 answer Di = 2 ie carbon dioxide molecules contain two oxygen atoms (CO2) Calderglen High School

What is meant by the prefix:- Tri? 10 answer Tri = 3 ie sulphur trioxide molecules contain three oxygen atoms (SO3) Calderglen High School

What is meant by the prefix:- Tetra? 11 answer Tetra = 4 ie carbon tetrachloride molecules contain four chlorine atoms (CCl4) Calderglen High School

What is the chemical formula of carbon tetrachloride? 12 answer CCl4 Calderglen High School

Use the prefix method to name the compound with the formula N2O4 13 answer Dinitrogen tetroxide (tetraoxide) Calderglen High School

14 Valency = combining power of an atom Group 1 2 3 4 5 6 7 8 What is VALENCY? answer Valency = combining power of an atom Group 1 2 3 4 5 6 7 8 Valency 1 2 3 4 3 2 1 0 Calderglen High School

What is the valency of the Group 7 elements? 15 answer 1 Calderglen High School

What is the valency of the Group 2 elements? 16 answer 2 Calderglen High School

Describe how to work out the chemical formula of a compound? 17 Describe how to work out the chemical formula of a compound? Symbols Valencies Swap Divide answer Calderglen High School

What is the chemical formula of hydrogen sulphide? 18 answer Symbols H S Valencies 1 2 Swap 2 1 Divide not needed here ANSWER: H2S Calderglen High School

What is the chemical formula of calcium oxide? 19 Symbols Ca O Valencies 2 2 Swap 2 2 Divide 2 1 2 1 answer ANSWER:CaO Calderglen High School

Write the formula for silver (I) chloride 20 Write the formula for silver (I) chloride Symbols Ag Cl Valencies 1 1 Swap 1 1 Divide not needed here answer ANSWER: AgCl Calderglen High School

What is the valency of iron in iron (III) oxide? 21 answer 3 Calderglen High School

Roman Numerals in brackets eg copper (II) chloride = valency 2 How is the valency of a transition metal shown in the names of its compounds? 22 answer Roman Numerals in brackets eg copper (II) chloride = valency 2 Calderglen High School