Answer:
We can use heat = mcΔT to determine the amount of heat, but first we need to determine ΔT. Because the final temperature of the water is 55°C and the initial temperature is 20.0°C, ΔT is as follows:
ΔT = Tfinal − Tinitial = 55.0°C − 20.0°C = 35.0°C
given the specific heat of water as 1 cal/g·°C. Substitute the known values into heat = mcΔT and solve for amount of heat:
= heat=(75.0 g)(1 cal/ g· °C )(35.0°C) =
= 75x1x35=2625 cal
Both are caused by human ignorance. Both have the ability to kill those in them. Both can become compact to create new material.
The given question is incomplete. The complete question is :
Which of the following Group 17 elements is the least reactive
a) Flourine
b) Chlorine
c) Astatine
d) Iodine
Answer: c) Astatine
Explanation:
Halogen is the name given to Group 17 family with general electronic configuration of 
which have 7 valence electrons and thus easily gain one electron to attain stable configuration.
As we move down the group from flourine to chlorine to bromine to iodine to astatine , the valence shell moves farther from nucleus and thus tendency to accept the electron decreases and thus reactivity also decreases.
Thus Astatine is the least reactive of all.
Atoms<span> are </span>arranged in molecular compounds in groups.
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For </span>covalent compounds<span>: </span>
<span>consider drawing the lewis structure of the covalent compound in question, putting the atom which is least electronegative (save hydrogen) in the center.
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