The answer is B as isotopes are different versions of the same chemical element containing the same amount of protons and electrons but different amounts of neutrons.
Answer:
1) Endothermic.
2)
3)
Explanation:
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1) In this case, for these calorimetry problems, we can realize that since the temperature decreases the reaction is endothermic because it is absorbing heat from the solution, that is why the temperature goes from 22.00 °C to 16.0°C.
2) Now, for the total heat released by the reaction, we first need to assume that all of it is released by the solution since it is possible to assume that the calorimeter is perfectly isolated. In such a way, it is also valid to assume that the specific heat of the solution is 4.184 J/(g°C) as it is mostly water, therefore, the heat released by the reaction is:
3) Finally, since the enthalpy of reaction is calculated by dividing the heat released by the reaction over the moles of the solute, in this case NH4Cl, we proceed as follows:

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Answer:
both
Explanation:
Carbon in the air around the living thing is moving in and out of its lungs. The movement is occurring at the same time. This is one of the most important gaseous exchange important to life.
- The goats takes in oxygen gas from the surrounding and releases carbon dioxide in the process.
- But, air is actually drawn in by the goat which is a mixture of several gases.
- Air contains carbon dioxide which is a rich source of carbon
- With the carbon dioxide from respiratory processes, the goat ejects and breathes out this waste carbon matter.
- Therefore, the gaseous exchange in a goat involves the movement of carbon in and out of the air.
The number of bacteria is given by:
N(t) = N(o) x 2ⁿ
Where N(t) is the number after n hours have passed and N(o) is the original number which is 15.
The number grown in the 12th hour is the difference in the number after the 11th and the 12th hour. Thus:
15 x 2¹² - 15 x 2¹¹
= 30,720 bacteria
Explanation:
the physical and chemical properties of an element are periodic functions of their atomic number.