To measure the speed of a car, we use miles per hour (miles/hour or mi/h or mph). to measure the rate of a reaction we use molar concentration per second (m/s).part aimagine that you took a road trip. based on the information in the table, what was the average speed of your car? time mile marker3: 00 pm 208: 00 pm 241express your answer to three significant figures and include the appropriate units. use mi as an abbreviation for miles, and h for hours, or mph can be used to indicate miles per hour. part bnow consider the following reaction and data: h2+2icl→2hcl+i2time(s) i2 concentration(m)5 1.1115 1.83what is the average rate of formation of i2? express your answer to three decimal places and include the appropriate units. part cbased on your answer to part b, what is the average rate of formation of hcl? express your answer to three decimal places and include the appropriate units.

Part A: 47.8 mi/h

Part B: 0.072 M/s

Part C: 0.144 M/s

Explanation:

Part A

The average speed or velocity (V) is the variation of the space divided by the variation of the time:

V = (241 - 2)/(8 -3)

V = 47.8 mi/h

Part B

As Part A, the average rate (r) of formation of I2 is the variation of the concentration divided by the variation of time:

r = (1.83 - 1.11)/(15 - 5)

r = 0.072 M/s

Part C

The rates of the substances are proportional of their number of moles (n) which are their coefficient, so:

rI2/nI2 = rHCl/nHCl

0.072/1 = rHCl/2

rHCl = 2*0.072

rHCl = 0.144 M/s

pre-sliced bread is a relatively recent development in baking technology. previous to that, it was always sold in a bakery in daily-made contiguous loaves with no wrapping, and was moderately perishable, usually being used with a day or two (which is why every bakery had a discounted “day-old” bread table.) therefore, pre-sliced bread would grow stale quickly. the hard crust provided a protective layer, and once the exposed dry slice left from the previous cut was removed, the interior was still soft.

what keeps bread soft is the moisture retained in the crumb (the light spongy part that’s not crust). the reason the crust develops is the surface of the dough gets exposed to hot dry air during baking which browns the outer layer and seals it, preventing all the moisture from escaping the dough. longer exposure to air will also eventually cause your bread to lose flavor and become stale.

people were used to cutting slices as they needed them and storing bread in a specially-made wooden or metal breadbox or pail with a lid to preserve it longer, but the first automatically sliced commercial loaves were produced on july 6, 1928, in chillicothe, missouri, using a machine invented by otto rohwedder, an iowa-born, missouri-based jeweler.[1] pre-sliced bread would indeed dry out, were it not for another 20th century technology: the plastic bag. bread could now be pre-sliced, and if the enclosing bag remains sealed as much as possible, the bread will remain soft and fresh for longer than if sitting unwrapped on a shelf or enclosed in a bread box that is not air-tight. sealed packaging meant bread could also be sold on store shelves and eliminate frequent trips to a bakery.

sealing bread in a plastic bag had another effect: the moisture in the loaf will re-distribute into the crust and soften it, which is sometimes more pleasing in a sandwich - especially for children whose teeth might not yet be strong enough to tear through a hard crust. a homemade loaf of bread can be sealed in a bag overnight and the crust will become soft like store-bought sandwich bread.

these were novel changes in how bread was produced and sold, which led to the coining of the phrase “the greatest thing since sliced bread.”

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.