A student lives in a place that receives lots of snow and ice during the winter. The student has observed that the highway department spreads salt on the road after a snowfall. Which of the following correctly explains why the highway department uses salt on the roads? Salt lowers the freezing point of water, which makes the melted snow on the road less likely to form ice.

Salt raises the freezing point of water, which makes the melted snow on the road less likely to form ice.

Salt raises the vapor pressure of water, which makes the melted snow more likely to evaporate before it freezes.

Salt lowers the osmotic pressure of water, which makes the melted snow more likely to be absorbed into the ground before it freezes.

a basic solution is an aqueous solution containing more oh-ions than h+ions. in other words, it is an aqueous solution with a ph greater than 7. basic solutions contain ions, conduct electricity, turn red litmus paper blue, and feel slippery to the touch.

explanation:

part 1: the half-life of the element is 22 years.

part 2: it will take 132.02 year for the sample to decay from 308.0 g to 4.8125 g.

explanation:

part 1: there are two ways to determine the half life time.

first way: the half life time can be determined directly from its definition as it is the time required for the sample to decay to its half concentration.

from the data the initial concentration was 45.0 g and decayed to its half value (22.5 g) in 22.0 years.

second way: the radio active decay is considered first order reaction so we can use the laws of first order reactions.

k = (1/t) ln (a/a-x), where k is the rate constant of the reaction,

t is the time of the reaction

a is the initial concentration of the reactant

a-x is the remaining concentration at time (t)

a = 45.0 g the initial concentration at t = 0 year.

at t = 22 year, a-x = 22.5 g

then k = (1/22 year) ln (45.0 g/ 22.5 g) = 0.0315 year-1.

the half-life time (t1/2) = ln 2/ k = 0.693/ k =0.693/ 0.0315 = 22 years.

part 2:

using the same law k = (1/t) ln (a/a-x),

using the given data; a = 308.0 g and a-x = 4.8125 g and the calculated k from the part 1 (k = 0.0315 year-1)

t = (1/k) ln (a/a-x) = (1/0.0315) ln (308.0/ 4.8125) = 132.02 years

while cooking a piece of 1/2 pound beef steak, a cast iron pan (2.4kg in weight) was heated 260 celsius.

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