C3 : MOLE-MASS-NO.PARTICLE CONVERSIONS

Relationship between mole, mass, Ar @ Mr and no. of particles

SOURCE: http://elementlearning.com/

Converting Mass to Moles & Moles to Mass  (by using Mr @ Ar)

Converting Moles to Mass (multiply by the molar mass)

1. How many grams are in 2.4 moles of sulfur?
ans : 2.4 x  32 = 76.8 grams

2. How many grams are in 238 moles of arsenic?  
ans : 238 x 75   = 17,850 grams

3. How many grams are in 11.9 moles of chromium?  
ans : 11.9 x 52   = 618.8 grams

4. How many grams are in 88.1 moles of magnesium?  
ans : 88.1 x 24 = 2114.4 grams

5. How many grams are in 4.5 moles of sodium fluoride, NaF?  

ans : 4.5 x 42 = 189 grams

6. How many grams are in 0.02 moles of beryllium iodide, BeI₂?  

ans : 0.02 x  263   = 5.26 grams

7. How many grams are in 3.3 moles of potassium sulfide, K₂S?  

ans : 3.3 x 110    = 363.0 grams

Converting Mass to Moles (divide by the molar mass)

1. How many moles are in 15 grams of lithium?  
ans : 15 / 7 = 2.14 moles

2. How many moles are in 22 grams of argon?  
ans : 22 / 40 = 0.55 moles

3. How many moles are in 2.3 grams of phosphorus?  
ans : 2.3 / 31 = 0.074 moles

4. How many moles are in 10.5 grams of magnesium?  
ans : 10.5 / 24 = 0.438 moles

5. How many moles are in 68 grams of copper (II) hydroxide, Cu(OH)₂? 
ans : 68 / 99 = 0.69 moles

6. How many moles are in 98.3 grams of aluminum hydroxide, Al(OH)₃? 
ans : 98.3 / 78 = 1.26 moles

7. How many moles are in 9.54 grams of silicon dioxide, SO₂?
ans : 9.54 / 64 = 0.149 moles


Converting Number of Particles to Moles & Moles to Number of Particles 

Converting Moles to No.of atoms/molecules/ions (multiply by the N_A)

1. How many atoms in 3.0 moles of Ar?
ans : 3.0 x  6.02 x 10²³ = 1.806 x 10²⁴ atoms

2. How many atoms in 8.5 moles of Fe?
ans : 8.5 x  6.023 x 10²³ = 5.117 x 10²⁴ atoms

3. How many molecules in 2.0 moles of CO₂?
ans : 2.0 x  6.023 x 10²³ = 1.204 x 10²⁴ molecules
ans : no.of C atom = 1.204 x 10²⁴ x 2 = 

4. How many molecules in 1.8 moles of PCl₃?
ans : 1.8 x  6.023 x 10²³ = 1.0836 x 10²⁴ molecules

5. How many molecules in 2.5 mol aluminuim sulphate, Al₂(SO₄)₃
ans : 2.5 x  6.023 x 10²³ = 1.505 x 10²⁴ molecules

6. How many molecules in 0.25 mol of scandium(III) oxide, Sc₂O₃.
ans : 0.25 x  6.023 x 10²³ = 1.505 x 10²³ molecules

Converting Mass to Moles (divide by the N_A)