Question

1 The densities of several common metals are listed below. Compare your experimental density with the given values and try to determine which metal you tested.  What other properties could be used to help identify your metal?  

2 Osmium metal, the densest element, has a density of 2.6 g/mL, while hydrogen, the least dense element, has a density of 8.99 times 10^-5 g/mL. Calculate volume occupied by 1.00 g of each element. How many times more dense is osmium than hydrogen?

3 A piece of aluminum foil is 0.0150 cm thick. Calculate the thickness of the aluminum foil in terms of the number of aluminum ATOMS. Assume that the aluminum atoms are spheres with a radius of 143 pm, and that they are stacked one on top of another.

Answer 1

1)

Other properties, for e.g. melting point, boiling point, ductility, color, malleability and elasticity are used to identify the metals.

2)

Given

Density of Osmium = 22.6 g/ml

Mass of Osmium = 1.00 g

We can calculate volume of Osmium by using formula

V= m/d

V = 1.00g /22.6 g/ml

Volume of Osmium = 0.044ml

Density of Hydrogen = 8.99 x 10^-5 g/ml

Mass of hydrogen = 1.00g

V= m/d

V = 1.00g / 8.99 x 10^-5 g/ml

V = 1.11 x 10⁴ml

Volume of Hydrogen = 1.11 x 10⁴ml

We can compare the density by dividing the density of Osmium by density of Hydrogen

= (22.6 g/ml)/ (8.99 x 10^-5 g/ml) = 2.51 x 10^5

Osmium is 2.51 x 10^5 times denser than Hydrogen.

3)

Thickness of aluminum foil = 0.0150 cm

1 cm = 10^10 picometre

So, Thickness of aluminum foil in pm = 0.0150 x 10^10 = 1.5 x 10^8 pm

Assume that the aluminum atoms are spheres with a radius of 143 pm, and that they are stacked one on top of another

So, the thickness of 1 atom of aluminum is its diameter = 143 x 2 = 286 pm

The thickness of the aluminum foil in terms of the number of aluminum ATOMS = 1.5 x 10^8 pm/286 pm

The thickness of the aluminum foil in terms of the number of aluminum atom = 5.24 x 10^5 atoms Al