Questions using Moles

Useful Terms:­

Avogadro's number = 6 x 1023

Number of moles =

Mass

 

Number of moles=

Molarity  x  Volume

 

Atomic/Molar mass

 

 

1000

 

1)  What is the mass of :­

a)                      moles of zirconium atoms Zr?

b)                      0.02 moles of Thorium atoms Th?

c)                       moles of Nickel atoms Ni?

d)                      moles of Mercury atoms Hg?

e)                      moles of Phosphorous molecules P4?

 

2) Calculate the mass of :

a)                      1 mole of H2?

b)                      1 mole of H?

c)                       1 mole of SiO2?

d)                      0.5 moles of NaCl?

e)                      0.25 moles of Na2CO3.10H2O?

 

3) How many moles of :­

a)                      32g of oxygen molecules?

b)                      32g of oxygen atoms?

c)                       31g of phosphorous molecules P4?

d)                      32.g of sulphur molecules S8?

 

4) The formula of Sodiumdihydrido - bis ( 2 - methoxy ethoxy) Aluminate is abbreviated SDA for ease :­

NaAlH2(OCH2CH2OCH3)2

 

a)                      How many moles of Na atoms are there in 1 mole of SDA?

b)                      How many moles of carbon are there in 1 mole of SDA?

c)                      How many atoms of Al are there in 1 mole of SDA?

d)                      How many atoms of H are there in 1 mole of SDA?

e)                      What is the total number of moles of atoms of all the elements in 1moIe of SDA?

 

5) 1mole of sodium and 1 mole of iron must have the same:

Choose one :- a) mass     b) density     c) volume     d) number of atoms     e) number of electrons

 

6) Which of the following contains the greatest proportion of nitrogen by mass?

 

a)

Ammonium Sulphate

(NH4)2SO4

RAM = 132

b)

Ammonium carbonate

(NH4)2CO3

RAM = 96

c)

Ammonium nitrate

NH4NO3

RAM = 80

d)

Ammonium ethanoate

CH3COONH4

RAM = 77

e)

Ammonium chloride

NH4Cl

RAM = 53.5

 

7) The Avogodro number is 6 x 1023 which is the same number as:  ­Choose one

a)                      Hydrogen atoms in 18g of water.

b)                      Hydrogen molecules in 1g of Hydrogen.

c)                       Oxygen atoms in 44g of carbon dioxide.

d)                      Nitrogen molecules in 28g of nitrogen.

 

8) The decomposition of an oxide of sulphur gave 3.2g of sulphur and 3.2g of oxygen. What is the formula of the oxide of sulphur?

 

9) What mass of aluminium contains the same number of atoms as there are molecules of 22g of carbon dioxide?

 

10) Copper (II) sulphate is CuSO4.5H2O. What is the mass lost by 5g of Copper (II) sulphate if all the water is driven off?