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: The correct answer is option B.
Explanation:
- Ionic bond is formed when there is complete transfer of electrons from one element to another.
- Covalent bond is formed by the sharing of electrons between two elements.
- Metallic bond is formed when two metals combine together.
Electronic Configuration of Group VII-A : 
This group require 1 electron to attain stable electronic configuration.
Electronic configuration of Group I-A : 
This group will loose 1 electron to attain stable electronic configuration.
So, there will be complete transfer of electron from Group VII-A to Group I-A and hence, will form ionic bond between them.
Hence, the correct option is B.
Calcium oxide CaO = 40+16 = 56
Calcium hydroxide Ca(OH)_2 = 40+16+16+1+1 = 74
The ratio 56:74 is equal to 14:x with x being the unknown mass.
56/14 = 4
74/4 = 18.5
So the answer is 18.5g assuming the water is in excess
Answer:
Option B: cooling as the lava runs down the mountain
Explanation:
The point R is basically at near the Earth's surface.
Now, we are told that rocks melt underground to form magma. This is a process of formation of igneous rocks. So, in formation of igneous rocks another process that will contribute to formation of rocks at point R is named cooling.
Cooling is a process where the larva runs down the mountain that makes magma hardened and makes it it turn into igneous rock.
