The piece of unknown metal is in thermal equilibrium with water such that Q of metal is equal to Q of the water. We write this equality as follows:
-Qm = Qw
Mass of metal (Cm)(ΔT) = Mass of water (Cw) (ΔT)
where C is the specific heat capacities of the materials.
We calculate as follows:
-(Mass of metal (Cm)(ΔT)) = Mass of water (Cw) (ΔT)
-68.6 (Cm)(52.1 - 100) = 42 (4.184) (52.1 - 20)
Cm = 1.717 -----> OPTION C
The relative volumes of chloroform and water that should be used is 9:10
Concentration of solution in chloroform =
( moles of chloroform )
Concentration of solution in water =
( moles of water )
Dissociation constant at
; 
Concentration of solution in chloroform / Concentration of solution in water
Meaning;

Since
mole is present in chloroform and
mole is present in water, Total mole of Caffeine present is 
Now, we substitute our given values into the equation

Therefore, the relative volumes of chloroform and water that should be used is 9:10
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Answer:
1230
Explanation:
1.20×1025=1230 is your answer
Answer:
Be
Explanation:
Reactivity increases from left to right and decreases from the top of the column to the bottom of column