A certain substance X condenses at a temperature of 147.2 °C. But if a 800. g sample of X is prepared with 77.9 g of urea ((NH2)2Co) dissolved in it, the sample is found to have a condensation point of 150.7 °C instead. Calculate the molal boiling point elevation constant Kb of X.
Be sure your answer has the correct number of significant digits

Which element in the third period would you expect to have the larger atomic radius, sodium (na) or sulfur (s)? a. sodium, because it has a higher effective nuclear charge attracting electrons in fewer energy levels. b. sodium, because it has fewer protons attracting electrons in the same energy levels. c. sulfur, because it has more protons attracting electrons in more energy levels. d. sulfur, because it has a higher effective nuclear charge attracting electrons in the same energy levels.

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

The valence of aluminum is +3, and the valence of the chlorine is -1. the formula fir the aluminum chloride is correctly written as