Numericals on Mole Concept Class 9

Which of the following has the most number of moles present?

• 5.75 g of Na (Sodium)

• $3.011\ \cdot\ 10^{23\ }$ atoms of Cl (Chlorine)
  

• 96 g of S (Sulphur)

• $6.022\cdot10^{23}$ atoms of Pb (Lead)
  

Calculate the mass of

 $0.75275\ \cdot10^{23}$  atoms of Calcium

• 5 g

• 10 g

• 40 g

• 20 g 

• None of the above

One atom of element X weighs

 $6.644\ \cdot10^{-23}$  g . Name element X and categorize it as a metal or non-metal

• Phosphorus, Non-Metal

• Calcium, Metal

• Scandium, Non-Metal

• Potassium, Metal

Calculate the formula mass of  $NaHCO_3$  

• 81 u

• 82 u

• 83 u 

• 84 u 

20 g of Water = X moles . Find X

• 1.15

• 1.13

• 1.11

• 1.12

Calculate the number of Aluminium ions present in 0.051 g of Aluminium Oxide

• $6.022\cdot10^{19}$ ions

• $6.022\cdot10^{20}$ ions

• $3.001\cdot10^{19}$ ions

• $3.001\cdot10^{18}$ ions

Find the molar mass of Ethyne  $C_2H_2$  

• 24 g

• 25 g

• 26 g 

• 24 g 

Calculate the molar mass of 2.8 moles of Calcium Carbonate

• 280 g

• 560 g

• 140 g

• 70 g

Calculate the mass of 0.5 moles of  $N_2$  gas

• 7 g

• 6 g

• 6.98 g 

• 7. 2 g

• None of the above

What is the atomic mass of an element whose two isotopes are present in the ratio 3:1? (The element is used as a disinfectant)

• 35 u

• 36 u

• 35.45 u

• 36.5 u

• None