Students are studying how two substances react. the students mix substance 1 with substance 2 in a solution. later the students boil the solution, releasing substance 1 as a gas and leaving substance 2 as a solid. what type of change is described in the paragraph above? how do you know? this is a chemical change, because the two substances were mixed together. this is a chemical change, because the two substances were separated chemically by boiling. this is a physical change, because the two substances were separated physically by boiling. this is a chemical change, because a gas was released.

Temperature and kinetic energy are proportional. a) adirectly b) directly c) indirectly

A100-watt light bulb radiates energy at a rate of 100 j/s. (the watt, a unit of power or energy over time, is defined as 1 j/s.) if all of the light emitted has a wavelength of 525 nm , how many photons are emitted per second?

These questions are based on the attached photo. the experiment is about burning magnesium metal with oxygen. 1. write the balanced chemical equation for the reaction you are performing. 2. calculate the mass of magnesium metal used in each trial. o trial 1: o trial 2: 3. calculate the actual yield of magnesium oxide for each trial. o trial 1: o trial 2: 4. magnesium is the limiting reactant in this experiment. calculate the theoretical yield of mgo for each trial. o trial 1: o trial 2: 5. determine the percent yield of mgo for your experiment for each trial. o trial 1: o trial 2: 6. determine the average percent yield of mgo for the two trials. your company currently uses a process with a similar cost of materials that has an average percent yield of 91 percent. if the average percent yield of this process is higher than that, this could save the company money. what is your recommendation to the company? support your recommendation using your data, calculations, and understanding of stoichiometry gathered from this lab.