Answer:
heat will flow from your hand (the warmer object) to the cup (the colder object), and your hands will start to feel cold because their losing heat energy
The type of reaction that occurs without the addition of heat is called spontaneous reaction. That is option D.
<h3>What is spontaneous reaction?</h3>
Spontaneous reaction is defined as the reaction where by new substances are formed naturally without the addition of extra energy in the form of heat.
Therefore, the type of reaction that occurs without the addition of heat is called spontaneous reaction
Learn more about heat here:
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<u>Answer:</u> The sample of Carbon-14 isotope will take 2377.9 years to decay it to 25 %
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:

where,
= half life of the reaction = 5730 years
Putting values in above equation, we get:

Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = ? yr
= initial amount of the sample = 100 grams
[A] = amount left after decay process = (100 - 25) = 75 grams
Putting values in above equation, we get:

Hence, the sample of Carbon-14 isotope will take 2377.9 years to decay it to 25 %
Answer:
Lipids
Explanation:
Lipids perform many different functions in a cell. Cells store energy for long-term use in the form of lipids called fats. Lipids also provide insulated from the environment for plants and animals
Answer:
Una cuenca es un área de tierra que drena todos los arroyos y la lluvia a una salida común, como la salida de un embalse, la boca de una bahía o cualquier punto a lo largo del canal de un arroyo.
Explanation:
Espero que esto ayude a marcar el MÁS CEREBRAL !!!