6

Estimate the surface-to-volume ratio of a C60 fullerene by treating the molecule as a hollow sphere and using 77pm for the atomi

AleksAgata [21]

Answer:

The surface-to-volume ratio of a C-60 fullerene is 3:77.

Explanation:

Surface area of sphere = $S=4\pi r^2$

Volume of the sphere = $V=\frac{4}{3}\pi r^3$

where : r = radius of the sphere

Radius of the C-60 fullerene sphere = r = 77 pm

Surface area of the C-60 fullerene = $S=4\pi (77 pm)^2$ ...[1]

Volume area of the C-60 fullerene = $V=\frac{4}{3}\pi (77 pm)^3$ ..[2]

Dividing [1] by [2]:

$\frac{S}{V}=\frac{4\pi (77 pm)^2}{\frac{4}{3}\pi (77 pm)^3}$

$=\frac{3}{77}$

The surface-to-volume ratio of a C-60 fullerene is 3:77.

7 0

2 years ago

Are substances that taste bitter and feel slippery to the skin

frez [133]

Answer:

Explanation:

Bases are the substances which have a bitter taste and feel slippery.
Sulfuric acid is the most widely made industrial chemical in the world. It is used to make many products, including paper, paint, detergents, and fertilizers. Car batteries contain sulfuric acid. Feel The properties of a base solution include a bitter taste and a slippery feel.

4 0

3 years ago

When a piece of zinc metal is carefully placed in a beaker of strong acid, bubbles form on the surface of the metal and begin to

kati45 [8]

Answer:

A. a new substance is being produced.

Explanation:

The bubbles most likely indicates that a new substance is being produced by this reaction. In essence, we describe this sort of change as chemical change.

In a chemical change, new substances are usually produced. They are accompanied by the evolution or absorption of energy.

The reaction of Zinc with a strong acid to produce bubbles on the surface of the metal indicates a chemical change and the formation of a new kind of substance.

Take for example, let zinc reacts with hydrocholoric acid, HCl;

Zn + 2HCl → ZnCl₂ + H₂

Since Zn is higher than Hydrogen in the activity series, it will displace it from HCl and liberate hydrogen gas as a product. This will cause the bubbles observed in the reaction.

This is a chemical change and new products have been formed.

B and D are wrong because they are both physical changes.

C is wrong because no information about such is provided by the problem statement.

So, when a piece of zinc metal combines with a strong acid, a new kind of substance is produced.

8 0

2 years ago

using the soubility curve what is the solubilityof nh4cl in 10 mL of water at a temperature of 60 degrees Celsius

lukranit [14]

Answer:

Please, see attached two figures:

The first figure shows the solutility curves for several soluts in water, which is needed to answer the question.

The second figure shows the reading of the solutiblity of NH₄Cl at a temperature of 60°C.

Answer: 5.5g

Explanation:

The red arrow on the second attachement shows how you must go vertically from the temperature of 60ºC on the horizontal axis, up to intersecting curve for the solubility of NH₄Cl.

From there, you must move horizontally to the left (green arrow) to reach the vertical axis and read the solubility: the reading is about in the middle of the marks for 50 and 60 grams of solute per 100 grams of water: that is 55 grams of grams of solute per 100 grams of water.

Assuming density 1.0 g/mol for water, 10 mL of water is:

$10mL\times 1.0g/mL=10g$