Which sample is a pure substance?
a a test tube of zinc oxide
b a container of zinc and oxygen
c a flask of pond water
d a jar of soil

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Calculate - analysis of compound composed of iron and oxygen yields 174.86 of fe and 75.14g of o. what is the empirical formula for this compound?

Someone offer some answers to this, i will give 98 coins and mark as brainliest! i will put the rest of the lab down in the comments, solutions pre-lab questions: in this lab, you will make fruit drinks with powdered drink mix. complete the pre-lab questions to get the values you need for your drink solutions. calculate the molar mass of powered fruit drink mix, made from sucrose (c12h22o11).using stoichiometry, determine the mass of powdered drink mix needed to make a 1.0 m solution of 100 ml. (hint: use molarity = to find the moles of drink mix, then convert moles to grams using a mole conversion.)what mass of powdered drink mix is needed to make a 0.5 m solution of 100 ml?