Measurements of water quality were taken a river downstream from an abandoned chemical dumpsite. concentrations of a certain chemical were were obtained from 9 measurements taken at the surface of the water, 9 measurements taken at mid-depth of the water. and 9 measurements taken at the bottom of the water. what type of study was conducted, and what is the response variable of the study?
(a) an experiment was conducted, response variable is the connection of the chemical
(b) an experiment was conducted, response variable is the depth of the water
(c) a census was conducted, and the response variables is the depth of the water
(d) an observational study was conducted, and the response variable is the depth of the water

What is driving behind plate tectonics (plate movment)? a) gravity only b) inertia c) convection and gravity d) the sun theres no option for science so i picked chemistry. plz

Liv sheldon given the balanced equation for an organic reaction: c2h2 + 2cl2 → c2h2cl4 this reaction is best classified as *

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.