Francis is learning about dissolving at school. She reads descriptions about the rate of dissolving from four of her friends. George: The rate of dissolving can be fast or slow. The only thing you can do to speed up the rate of dissolving is to make the temperature hotter.
Manuel: The rate of dissolving can change. The rate of dissolving gets faster when the particles are smaller, the temperature is hotter, or the mixture is stirred.
Kim: The rate of dissolving speeds up when the particles are larger and the temperature is hotter. Stirring the mixture also helps increase the rate of dissolving.
Chris: The rate of dissolving can speed up or slow down. Heating a mixture, stirring a mixture, or using smaller particles will slow down the rate of dissolving.

Which of her friends has the best description about the rate of dissolving?

A George
B Manuel
C Kim
D Chris

What layer of the atmosphere is directly above the troposphere?

7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation. 8. when a 2.5 mol of sugar (c12h22o11) are added to a certain amount of water the boiling point is raised by 1 celsius degree. if 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed? show all calculations leading to your answer or use 3 – 4 sentences to explain your answer. 9. if 5.40 kcal of heat is added to 1.00 kg of water at 100⁰c, how much steam at 100⁰c is produced? show all calculations leading to an answer. 10. the freezing of water at 0⁰c can be represented as follows: h2o (l) ↔ h2o(s) the density of liquid water is 1.00 g/cm3. the density of ice is 0.92 g/cm3. in 3 – 4 sentences explain why applying pressure causes ice to melt.

To find the enthalpy of a reaction in the lab, you measured the of the reactants and the change during the reaction.