You have a 0.7 M solution. Your job is to produce 50 mL of a 0.4 M solution. A. How much of the 0.7 M solution do you need to start with? (Show your work.)

B. How many moles of solute were in the 0.7 M solution? (Show your work.)

C. How much water do you need to add to the previous amount of the 0.7 M solution to dilute it to

0.4 M? (Show your work.)

D. A student decides to put double the amount of water calculated in Part C. Describe what effect this

will have on the overall concentration of the resulting solution. Justify your answer.

A. 28.6 ml of the 0.7 M solution we need to start with.

B. There are 0.02 moles of solute were in the 0.7 M solution.

C. Amount of water to be added is 21.4 ml

D. The resulting solution will have concentration of 0.28 M

Explanation:

According to the dilution law,

where,

= molarity of stock solution = 0.7 M

= volume of stock solution = ?

= molarity of diluted solution = 0.4 M

= volume of  diluted solution = 50 ml

Putting in the values we get:

A. 28.6 ml of the 0.7 M solution we need to start with.

B. Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

where,

n = moles of solute

= volume of solution in ml

Thus there are 0.02 moles of solute were in the 0.7 M solution.

C. Amount of water to be added = (50-28.6 ) ml = 21.4 ml

D. If water added is

If volume of concentrated solution will be more , the resulting solution will have lesser concentration of 0.28 M

answer: option (4) is the correct answer.

explanation:

areas which are at low altitudes and near the equator tend to receive direct sunlight from the sun. hence, heat energy or radiations from the sun make these areas warmer and they have warmest water.

whereas areas which are at high altitudes and away from the equator do no receive direct sunlight. hence, no direct contact from the sun makes these regions colder and thus, they have colder water.

thus, we can conclude that the statement areas at low latitudes near the equator have the warmest water because they receive the most direct sunlight best explains the relationship between an area's geography and the temperature of its surface water.