Can someone please help with science , I need help!!!
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The question is incomplete, the complete question is shown in the image attached to this answer.
Answer:
a) Br^-
b) FeCl3
c) slower
d) see the first attached image
Explanation:
Aromatic compounds undergo electrophilic substitution sections in the presence of the appropriate electrophile.
In the reaction above, the Br^- nucleophile attacks the Lewis acid FeCl3. Recall that the nitro group is meta directing hence the incoming Br^+ electrophile is directed towards the meta position as shown in the image attached.
Note that the nitro group deactivates the ring towards electrophilic substitution hence the reaction is slower with nitrobenzene than with unsubstituted benzene.
Ryan calculates that he requires 4 ice cubes for 250mL of hot tea to reach the optimal drinking temperature by using the specific heat capacity of tea.
A substance's potential to hold heat is indicated by its specific heat capacity. This substance size reflects the amount of heat required to raise a certain volume of a material's temperature by one Kelvin. Specific heat capacity is a distinguishing feature of every substance and is useful for material identification.
Given:
Final temperature of system is 57.8℃
dT1 = 79.1 - 57.8 = 21.3℃
dT2 = 0 - (-8.33) = 8.33℃
dT3 = 57.8 - 0 = 57.8℃
Mass of tea, m1 = 250.0mL = 250.0g = 0.250kg
Specific heat capacity of tea, C1 = 4186 J/kg℃ = Specific heat capacity of water
Specific heat capacity of ice, Ci = 2090 J/kg℃
Mass of each ice cubes, m of i = 18.8g
Latent heat of fusion of ice, Lf = 334 kJ/kg
To find:
No. of ice cubes required = ?
Calculations:
Suppose equilibrium temperature is T, then
Heat released by Tea = Heat gained by Ice
Q1 = Q2
m1x C1x dT1 = mi x Ci x dT2 + mi x Lf + mi x Cw x dT3
0.250x 4186 x 21.3 = mi x (2090 x 8.33 + 3.34 x + 4186 x 57.8)
mi = 0.250 x 4186 x 21.3 / (2090 x 8.33 + 3.34 x + 4186 x 57.8)
mi = 0.0761kg = 76.1g
Mass of ice required = 76.1g
Number of ice cube required will be:
n = Total mass of ice/mass of each ice cube
n = 76.1/18.8
n = 4.04 ice cubes = 4.0 ice cubes
Result:
Ryan requires 4 ice cubes to bring 250mL of hot tea to the optimal drinking temperature.
Learn more about Specific heat capacity here:
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