The mass of one mole of He is 4 grams. John’s experimental data indicated that the mass of 1 mole of He is 3.8 grams. What was his percent error? The density of nitrogen gas, N2, is 1.25 g/L. Laeni determined the density of N2 to be 1.35 g/L. What was her percent error?
Sean determined the volume of a penny to be 0.46mL. The teacher determined the volume of a penny to be 0.54mL. What was Sean’s percent error?

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.

In the lab, ammonia was mixed with water to form ammonium hydroxide. what is/are the reactant(s)? o water and ammonia o ammonia o ammonium hydroxide need

In medium-sized stars such as the sun, nuclear fusion almost always means the fusing of nuclei to form , but larger stars can produce elements as heavy as