Why does a closed system allow for more reliable measurements than an open system when observing a chemical reaction? A closed system conserves all of the product, allowing for an accurate measurement of its mass.
A closed system allows for some of the product to release into the area around the system, allowing the product to expand into all available space.
A closed system allows the activation energy to be reached more quickly.
A closed system allows the reaction to be viewed, increasing the possibility of seeing physical changes.

Use the table to identify the phase and phase changes of the elements under the given conditions. write the name of the substance, phase, or phase change

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.

Write a balanced equation showing the formation of copper (ii) nitrite from its elements