Answer:
Explanation:
hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhuh
The correct answers are options C, that is, silver tarnishes and becomes black when exposed to oxygen, and option E, that is, diesel fuel burns when it is heated.
Chemical changes refer to the modifications in which the chemistry at molecular level is modified as the initial substance gets transformed into a new and different final substance. This change occurs with the dissociation of old bond and production of new bonds respectively.
Silver gets tarnished and becomes black when exposed to oxygen. This refers to a chemical change as silver a white and lustrous substance gets transformed into a tarnish black final substance. However, silver does not easily react with oxygen at usual circumstances. It easily reacts with sulfur comprising components in the air and generates black compound as Ag₂S.
Burning of diesel fuel when it is heated. Diesel refers to a mixture of hydrocarbons varying approximately from C₁₀H₂₀ to C₁₅H₂₈. When these hydrocarbons get burnt they generate novel substances, that is, carbon dioxide and water. Hence, it is also a chemical reaction.
Until well in the 60ties, the luminous dials of wrist watches and alarm clocks were marked with luminous paints containing Radium (Ra-226) or Promethium (Pm-147). These kind of watches are no longer manufactured today. This is not due to the radiation exposure to the persons wearing the watches but because of the radiological risk for the persons manufacturing them.
Hope this helps
Answer:
See explanation
Explanation:
When a substance is heated, its average kinetic energy increases as the molecules move faster owing to the supply of energy. The solvent molecules are able to collide more frequently with the solute molecules and dislodge them so that the solute can dissolve in the solvent.
However, when a gaseous solute is dissolved in a liquid; as the temperature is increased and solvent molecules are able to collide more frequently with the solute molecules and dislodge them, gas molecules dissolved in the liquid are more likely to escape to the gas phase and not return due to the increase in their kinetic energy.
Hence, solubility of gas solutes in water decreases as temperature increases.
>Electrons move in circular orbits around the nucleus. Electrons are held in an atom by their attraction to each other. Electrons are evenly distributed throughout a mixture of positive and neutral particles.<
