(a) Atoms are very small compared to objects on the macroscopic scale. The radius of a platinum atom is 139 pm. What is this value in meters and in centimeters? m cm ( b) The mass of a single platinum atom is 3.24*1022 g. Suppose enough Pt atoms were lined up like beads on a string to span a distance of 48.1 cm (19 inches) How many atoms would be required? ___atoms
What mass in grams of Pt would be used? ___g
Could you weigh out this amount of platinum using a typical laboratory balance? Yes or no?

(c) Taking the density of platinum metal to be 21.4 g/cm^3, calculate the mass of metal needed to form a piece of Pt wire with the same length as the distance in b, but with a diameter of atoms 1.50 mm. Hint: The volume of a cylinder is π times its radius squared times its height (V = πr^2h) ___g

How many platinum atoms does this represent? atoms

Kindly check explanation

Explanation:

pm = picometer

Radius of platinum atom = 139 pm

1 pm = 1 × 10^-12 m

Hence,

139 pm = 139 × 10^-12 m

1 pm = 1 × 10^-10 cm

Hence,

139 pm = 139 × 10^-10 cm

B) mass of a single platinum atom = 3.24 × 10²² g

To obtain the diameter of 1 platinum atom in cm:

139 × 10^-10 cm

Number of atoms required :

48.1 cm / 1.39 × 10^-8 cm = 34.60 × 10^8 atoms

Mass in gram of P(t) :

(3.24 × 10²²) × (34.60 × 10^8) = 112.117 × 10^(22+8)

= 112.12 × 10^30 g

C) density (d) = 21.4 g/cm^3, diameter = 1.50 mm

V = πr^2h

h = 48.1cm ; r = 1.5 / 2 = 0.75 mm = 0.075cm

Density = mass / volume

Volume = π * 0.075^2 * 48.1 = 0.8499971cm³

Mass = density × volume

Mass = 21.4g/cm³ × 0.8499971cm³

= 18.19g

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.