Atoms and molecules grade 9

A sample of NH₃ molecule irrespective of source contains 82.35% Nitrogen and 17.65% of Hydrogen by mass. This data supports:

• Law of conservation of mass

• Law of Multiple proportion

• Law of Constant proportion

• Avagradro law

The molecular formula of potassium nitrate is ________.

• KNO₃

• KNO

• KNO₂

• KON

Molecular mass is defined as the:

• Mass of one molecule of any substance compared with the mass of one atom of C – 12

• Mass of one atom compared with the mass of one atom of hydrogen

• Mass of one atom compared with the mass of one molecule

• None of the above

The atomic mass of sodium is 23. The number of moles in 46g of sodium is ________.

• 4

• 2

• 1

• 1.5

what is the symbol of Sodium?

• S

• So

• Na

• Sm

What is the atomicity of Carbondioxide?

• 1

• 2

• 3

• 4

The number of molecules in 16.0g of oxygen is:

• 6.022 x 10²³

• 6.022 x 10²²

• 3.011 x 10²³

• 3.11 x 10²³

What is the chemical symbol of Gold?

• Ag

• Au

• Go

• Gd

Identify the monoatomic species?

• Ammonia

• Water

• Helium

• Sulphur

What is the name of this compound: Mg3(PO4)2

• Trimagnesium phosphate

• Trimagnesium di phosphate

• Magnesium phosphite

• Magnesium phosphate