The concept to be used in order to determine the diameter of the second cell in the photograph is that of the ratio and proportion. The ratio of the first set of measurements should be proportional (equal) to the ratio of the second set.
Ratio of first set of diameters,
r = diameter of Cell A / diameter of Cell B
r = 12 micrometers/20 micrometers
r = 3/5
If we let D be the diameter of the cell B in photographs,
r = 3/5 = 15 cm/x cm
The value of x from the equation is 25. Hence, the diameter of cell B is 25 cm.
Answer:
ΔH = - 11758.6 J/mol = - 11.76 kJ/mol
Explanation:
Step 1: Data given
Mass of arsenic tribromide = 54.7 grams
MAss of water = 300.0 grams
Temperature of water = 22.50 °C
Final temperature of water = 24.13 °C
Step 2: Calculate ΔH
Q= m*c*ΔT
⇒with m =the mass of water = 300.0 grams
⇒with c= the specific heat of water = 4.184 J/g°C
⇒with ΔT = the change in temperature of water = T2 - T2 = 24.13 - 22.50 = 1.63 °C
Q = 300 * 4.184 * 1.63
Q = 2046 J
Step 3: Calculate moles AsBr3
Moles AsBr3 = mass / molar mass
Moles AsBr3 = 54.7 grams / 314.634 g/mol
Moles AsBr3 = 0.174 moles
Step 4: Calculate ΔH
ΔH = -Q/moles
ΔH = -2046 J / 0.174 moles
ΔH = - 11758.6 J/mol = - 11.76 kJ/mol