Answer:
A toilet requires a large amount of cold water to flush. So, when the toilet flushes while you're in the shower, it's stealing from your shower's cold water supply. When the pressure-balancing valve senses the drop in cold water pressure, it responds by restricting the hot water pressure.
<span>C. Gravity acts on all objects in the universe.
think about Newtons Laws of Motion</span>
Answer : The amount of heat evolved by a reaction is, 4.81 kJ
Explanation :
Heat released by the reaction = Heat absorbed by the calorimeter + Heat absorbed by the water
![q=[q_1+q_2]](https://tex.z-dn.net/?f=q%3D%5Bq_1%2Bq_2%5D)
![q=[c_1\times \Delta T+m_2\times c_2\times \Delta T]](https://tex.z-dn.net/?f=q%3D%5Bc_1%5Ctimes%20%5CDelta%20T%2Bm_2%5Ctimes%20c_2%5Ctimes%20%5CDelta%20T%5D)
where,
q = heat released by the reaction
= heat absorbed by the calorimeter
= heat absorbed by the water
= specific heat of calorimeter = 
= specific heat of water = 
= mass of water = 254 g
= change in temperature = 
Now put all the given values in the above formula, we get:
![q=[(783J/^oC\times -2.28^oC)+(254g\times 4.184J/g^oC\times -2.28^oC)]](https://tex.z-dn.net/?f=q%3D%5B%28783J%2F%5EoC%5Ctimes%20-2.28%5EoC%29%2B%28254g%5Ctimes%204.184J%2Fg%5EoC%5Ctimes%20-2.28%5EoC%29%5D)
Therefore, the amount of heat evolved by a reaction is, 4.81 kJ
The reaction of iron sulfide (FeS) with hydrochloric acid (HCl) results in the formation of ferrous chloride (FeCl2) and hydrogen sulfide (H2S) gas. The reaction can be shown as follows:
FeS (s) + HCl(aq) ---- FeCl2(s) + H2S(g)
The bubbles indicate the formation of H2S gas which is a chemical change. The formation of bubbles indicates this change as it suggests that the reactants are combing to form products i.e. it signals a chemical reaction.
