Question #1 Compare how entropy changes for the following two systems:

System A: Two gases mix when the valve separating two containers is opened.

System B: A solid powder decomposes to form a solid product and a gas product.

Question #2

A 3.81-gram sample of NaHCO3 was completely decomposed in an experiment.

2NaHCO3 → Na2CO3 + H2CO3

In this experiment, carbon dioxide and water vapors combine to form H2CO3. After decomposition, the Na2CO3 had a mass of 2.86 grams.

Determine the mass of the H2CO3 produced.

Calculate the percentage yield of H2CO3 for the reaction. Show your work or describe the calculation process in detail.

Consider three unlabeled bottles, each contain small pieces of one of the following metals. - magnesium - sodium - silver the following reagents are used for identifying the metals. - pure water - a solution of 1.0 molar hcl - a solution of concentrated hno3 (a) which metal can be easily identified because it is much softer than the other two? describe a chemical test that distinguishes this metal from the other two, using only one of the reagents above. write a balanced chemical equation for the reaction that occurs. (b) one of the other two metals reacts readily with the hcl solution. identify the metal and write the balanced chemical equation for the reaction that occurs when this metal is added to the hcl solution. use the table of standard reduction potentials (attached) to account for the fact that this metal reacts with hcl while the other does not. (c) the one remaining metal reacts with the concentrated hno3 solution. write a balanced chemical equation for the reaction that occurs. (d) the solution obtained in (c) is diluted and a few drops of 1 m hcl is added. describe what would be observed. write a balanced chemical equation for the reaction that occurs.

Why are pipes bursting in the in extremely cold weather?

Suppose the universe were completely empty except for one object-a solid sphere moving through space of 100 km/s. what sort of path would the object be moving in? explain your answer