Before Mendeleev published his periodic table, Johann Döbereiner grouped similar elements into triads, in which the unknown properties of one member could be predicted by averaging known values of the properties of the others. To test this idea, predict the the melting point of Br2 from the melting points of Cl2 (–101.0°C) and I2 (113.6°C)
a. –7.2 C
b. 12.6°C
c. 6.3°C
d. 214.6°C would it be d
(-101 + 113.6)/2 =
Now I see. I had figured it out in Kelvin, so 214 was the close. Thanks
To predict the melting point of Br2 using Döbereiner's triad concept, we would average the known melting points of Cl2 and I2.
The melting point of Cl2 is -101.0°C, and the melting point of I2 is 113.6°C.
To find the average, we add the two melting points and divide by 2:
(-101.0°C + 113.6°C) / 2 = 12.6°C
Therefore, the predicted melting point of Br2 based on Döbereiner's triad concept would be 12.6°C.
So the correct answer is option b. 12.6°C