Answer:
D. VISCOSITY can be defined as a substance's ability to resist flow.
Explanation:
This is the statement that correctly describe the term viscosity. Viscosity explains why substances or fluids resist flow. It shows that internal friction or resistance to flow revealed by a substance. A substance with high viscosity or internal friction resist flow and one with low viscosity flow easily. Viscosity of a substance change base on various factors affecting the substance such as pressure, temperature, surface area. Substances like water has low viscosity explaining why it flows easily.
Answer: Ethyl Ethanoate can be used as a developing solvent. It’s safer.
Explanation:Di ethyl ether should be carefully used because it’s highly flammable and intoxicating when inhaled and can cause explosions because of its high reactivity to air and light.
Answer:
Density of the He atom = 12.69 g/cm³
Explanation:
From the information given:
Since 1 mole of an atom = 6.022x 10²³ atoms)
1 atom of He = 

The volume can be determined as folows:
since the diameter of the He atom is approximately 0.10 nm
the radius of the He =
= 0.05 nm
Converting it into cm, we have:


Assuming that it is a sphere, the volume of a sphere is
= 
= 
= 
Finally, the density can be calcuated by using the formula :


D = 12.69 g/cm³
Density of the He atom = 12.69 g/cm³