The graph below compares the motion of particles in two substances. one substance is a gas and the other is a solid. a bar graph is shown with the title particle motion. the y axis title is particle speed. the x axis title is substance. there are two markings on the x axis. one is marked a and the other is marked b. the bar above a is lower than the bar above b. which statement best describes the two substances? particles are closer together in solids so substance b is a solid. particles are farther apart in solids so substance a is a solid. particles are farther apart in gases so substance b is a gas. particles are closer together in gases so substance a is a gas.

Answer is: Particles are farther apart in gases so Substance B is a gas.

For example, nitrogen molecules have weakest intermolecular bonds in gas phase and move fast and without order.  

Cooling is change from gas to solids. In solid state (for example ice) movement of molecules is more slow than movement of molecules in the gas (for example water vapor).

The process by which a solid changes directly to a gas without first becoming a liquid is called c. sublimation.

Sublimation is an endothermic process. For example dry ice (carbon(IV) oxide in solid state) is used because of sublimation in nightclubs, fog machines, at theaters, haunted house attractions.

Particles are farther apart in gases so Substance B is a gas.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%