Oxygen (O2) Carbon Dioxide (CO2)

Water (H2O)

contains 2 oxygen atoms per molecule

contains 2 oxygen atoms per molecule

contains 1 oxygen atom per molecule

gas at room temperature

gas at room temperature

liquid or gas at room temperature

flammable

not flammable

not flammable

A student compared some chemical and physical properties of three pure substances. Her data are recorded in the chart above. What is a logical conclusion the student can draw about pure substances?
A. Pure substances have the same chemical and physical properties.
B. Pure substances have the same chemical properties, but different physical properties.
C. Pure substances have the different chemical properties, but the same physical properties.
D. Pure substances have different chemical and physical properties.

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

Apiece of metal with a length of 1.42 cm was measured using four different instruments. which of the following measurements is the most accurate?

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.