Which factor explains why coal dust in an enclosed space is more explosive than coal dust blown outdoors into an open space ? a. temperature b. surface area c. concentration d. volume e. catalyst

Option C:- Concentration

Explanation:

Coal dust explosion can cause lots of damage. To avoid

this, the amount or concentration of coal dust per unit

volume or MEC is measured with the various conditions

of coal storage such as the particle size, moisture of coal,

degree of dispersion and delayed time of ignition source

to prevent the coal dust explosion which aims to study

and design the explosion safety measures for coal dust

handing installations. The results present that moisture

content in coal has more effect on dust explosion. The

smaller size of particle, low moisture in coal and high

coal dust dispersion can increase the possibility or risk of

dust explosion.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e