Answer: C. The sign of the enthalpy of the reaction reverses.
Explanation: Enthalpy of a reaction is the net heat absorbed or released during a chemical reaction.It is represented by 
. It is negative for exothermic reactions in which heat is released and is positive for endothermic reactions in which heat is absorbed.
When a chemical reaction is reversed the heat of the reaction changes its sign.
The decomposition of calcium carbonate is an endothermic reaction as heat is required to break the bonds and thus energy is absorbed.
When the reaction is reversed, the reaction becomes exothermic as now bonds are getting formed and energy is released.
Light travels extremely fast through the air, 300,000,000 m/s. Sound travels much slower, 343 m/s through air. Therefore we can see light in an instant, but it takes a while to hear thunder.
Explanation:
When you compare the numbers (speed of light vs speed of sound) you understand that light is 10^6 faster in speed that sound. When lightning occurs at a greater distance from the observer, this difference in speeds in more perceptible because the two different waves would have to travel greater distances to the observer and the relative differences in speed become increased.
Remember however, that sound travels in a medium while light waves do not require a medium because they are electromagnetic waves. In a vacuum, therefore, you would observe the lightning but never the sound.
Learn More:
For more on light and sound waves check out;
brainly.com/question/13402259
brainly.com/question/12779911
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Answer:
A dominant allele is a variation of a gene that will produce a certain phenotype, even in the presence of other alleles. A dominant allele typically encodes for a functioning protein. The allele is dominant because one copy of the allele produces enough enzyme to supply a cell with plenty of a given product.
Answer:
Blood clotting normally occurs when there is damage to a blood vessel.
Explanation:
Platelets immediately begin to adhere to the cut edges of the vessel and release chemicals to attract even more platelets. A platelet plug is formed, and the external bleeding stops.
Next, small molecules, called clotting factors, cause strands of blood-borne materials, called fibrin, to stick together and seal the inside of the wound. Eventually, the cut blood vessel heals and the blood clot dissolves after a few days.
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