Check my answers ? only 5 multiple choice questions. i'm really confused. any and all is appreciated! will give medal! 1. which of the following is a correctly written thermochemical equation? nh4cl nh4+ + cl 2c8h18 + 25o2 16co2 + 18h2o, h = 5,471 kj/mol fe (s) + o2 (g) fe2o3 (s), h = 3,926 kj --> c3h8 (g) + 5o2 (g) 3co2 (g) + 4h2o (l), h = 2,220 kj/mol 2. how does a phase change affect a thermochemical equation? it alters the moles of reactants. --> it can affect the (delta) h value. it alters the products. it affects the balance of the equation.

Which set of characteristics best describes igneous rock? a) largest type of rock, made of organic matter, hardest type of rock b) least abundant type of rock, made of other rocks, made mostly of minerals c) found on all continents, contains wavy bands of stripes, contains fossils d) most abundant type in earth's crust, made of magma/lava, contains no fossils

Apiece of copper has a temperature of 75.6 0c. when the metal is placed in 100.0 grams of water at 19.1 0c, the temperature rises by 5.5 0c. what is the mass of the metal?

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.