1. How many carbon atoms are there in this page? 2. In cellulose, how many carbo

Question

1. How many carbon atoms are there in this page?

2. In cellulose, how many carbon atoms would be stacked on top of each other to span the thickness of this page (the size of the page is 21.2 cm x 27.6 cm, and it is 0.07 thick)?

3. Now consider the problem from a different angel. Assume the page is compared only of carbon atoms. A carbon atom has a diameter of 2 x 10-10 m (0.2 nm); how many carbon atoms of 0.2 nm diameter would it take to span the thickness of the page?

4. Compare your answers from parts B and C and explain any differences.

Explanation / Answer

A. First we have to calculate molecular mass of cellulose. So, for a single cellulose unit, molecular formula is CH2O, and the molecular mass is 1*12+2*1+16*1=30 g (C=12gm, H=1gm, O=16 gm)

as per avagaro rule one mole of substance contains 6.022*1022 no. of atoms.

that means 30gm of cellulose (paper) contains 6.022*1022 no. of atoms. so, for 5 gm how much the answer is

5*6.022 * 1023
------------------------- = 1.004 * 1023
30

in cellulose only one carbon atom per unit, so there are about 1 * 1023 atoms of carbon.

B. For this, we have to calculate the density of the cellulose by dividing by the volume of the paper, which is 21.2cm * 27.6cm * 0.007 cm= 4.09584 cm3.

Density= weight/volume( 5gm/4.09584 cm3 )
You get 2.4414 * 1022 units/cm3. Then, you pretend you have a cube that has sides of 0.007 cm, and see how many units are in that, which is 8.408 * 1015. Since the cube is found by multiplying the 3 dimensions by each other and one of those dimensions is height, take the cube root to get 2.033 * 105.

C. Convert all quantities to meters so 0.007cm = 0.00007m)

0.00007/(0.2 * 10-9)=3.5*105 atoms

D. assuming they're all right next to each other.

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