Atoms and molecules

Atomic mass can be best defined as:

• 1/16th the mass of an oxygen atom

• 1/13th the mass of a carbon atom

• 1/12th the mass of a carbon atom

• 1/15th the mass of an oxygen atom

Nitrogen is

• Monovalent

• Divalent

• Trivalent

• Tetravalent

What is gold?

• element
• compound
• mixture

"Matter can be neither be created nor be destroyed" is stated by

• Law of defined proportions

• Law of conservation of mass

• Proust's law

• Dalton's Atomic theory

This is the molecule of:

• Sodium

• Sulphur

• Phosphorus

• Ozone

The reactants of the equation CO₂ + 2H₂ → CH₃OH is:

• CO₂ and H₂

• Only H₂

• CO_2,H₂ and CH₃OH

• CO₂ and CH₃OH

What does an atomic number represent?

• How much an atom weighs

• The number of protons or electrons

• The sum of protons and electrons

• The sum of protons and electrons

Which one of these is the correct symbol for mercury

• Me

• me

• Hg

• HG

which of the following statement is not correct ?

1. atoms are neutral

2. atoms are basic units of matter

3. atoms aggregate to form large molecules

4.atoms exist indepedently

• 1

• 3

• 2

• 4

In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B should have? 

• 4g
• 5g
• 9g
• 14g