Answer:
a solution color becoming less intense due to dilution- is not an evidence of a chemical reaction
bubbles (gas formation) - evidence of a chemical reaction
explosion or fire - evidence of a chemical reaction
changes in color- evidence of a chemical reaction
precipitation- evidence of a chemical reaction
changes in temperature - evidence of a chemical reaction
a solid liquifying - is not an evidence of a chemical reaction
solution colors mixing - is not an evidence of a chemical reaction
Explanation:
A chemical change is not easily reversible and yields new substances. It is often accompanied by a loss or gain of heat.
In the answer section, i have shown some evidences that lead us to conclude that a chemical reaction has taken place. The occurrence of a chemical change often goes with the formation of new substances as earlier stated and any of these signs may accompany the process.
For instance, when a metal is dropped in dilute acid solution, bubble of hydrogen gas indicates that a chemical reaction has taken place.
Answer:
Amount of heat energy released by light bulb = 25 joules
Explanation:
Given:
Energy receive by light bulb = 100 Joules
Energy released by light bulb as light energy = 75 Joules
Find:
Amount of heat energy released by light bulb
Computation:
We know that, energy is neither be created nor destroys
So,
Using Law of conservation of energy
Energy receive by light bulb = Energy released by light bulb as light energy + Amount of heat energy released by light bulb
100 = 75 + Amount of heat energy released by light bulb
Amount of heat energy released by light bulb = 100 - 75
Amount of heat energy released by light bulb = 25 joules
Answer:
Sue was not right as wood is not a heat conductor and will not allow heat to pass through the spoon thus keeping the hand safe. In a meatal spoon, heat can pass through and burn the hand as meatal is a good conductor of heat.
A. True
They are formed behind an obstacle when the wind blows the sand up to it.
