FACULTY OF ENGINEERING AND GEOSCIENCES
Metallurgical & Materials Engineering Department
Assignment 2 MOLECONCEPT CALCULATIONS: 25 marks
Due 12 November 2020
1. How many moles are in the following:
[6]
a. 1.29 x 1024 hydrogen atoms in HF
b. 7.36 x 1024 free oxygen atoms
c. 3.28 x 1023 Na atoms in salt (NaCl)
2. How many atoms are present in the following?
[9]
a. Hydrogen atoms in 3.14 mol of
b. Nitrogen atoms in 2.79 mol of NH3
c. Oxygen atoms in 4.90 mol in Al2O3
d. How many atoms are in a 3.56 g sample of Cu? What fraction of a Cu
mole is this?
3. What mass of Ni has as many atoms as there are N atoms in 63.0 g of NO2?
As Na atoms in 63.0 g of NaCl?
[4]
4. How many g of CaCO3 are present in a sample if there are 4.52 x 1024 atoms
of carbon in that sample?
[2]
5. How many molecules of HCl are in 4.91 L of HCl acid at 25°C if the density
equals 1.096 g/mL?
[2]
6. If a 3.785 L bottle were filled with bleach (NaClO), how many Cl atoms
would be in the bottle? bleach = 1.090 g/mL
7. At 25º C, the density of water is 0.997 g/ml. At -10º C, the density of ice is
0.917 g/cm3. If a bottle with a volume of 275 mL were filled fully with
water at 25º C and then frozen to -10º C, could the ice still be contained in
the bottle? What would the volume of the ice be?
[3]