To make lemonade, a recipe requires 4 lemons, 30 ounces of sugar, and 2 pints of water. from an average lemon one can squeeze out 0.4 cups of 5% citric acid. marta does not have lemons, but wants to make lemonade from 4 cups of 12% citric acid. if she has sugar and water in abundance, how much water will marta use?

She will need to add 5.6 cups of water

Explanation:

Hi there!

Marta has to dilute the citric acid to 5%.

The dilution factor will be 12%/ 5% = 2.4. Then, Marta will need to dilute the citric acid 2.4 times. If she has 4 cups of the solution, she will need to add water until she completes a volume of (4 cups ·2.4) 9.6 cups to reach the desired concentration.

Then, she will need to add 9.6 - 4 cups water = 5.6 cups of water

Another way to solve this is by using the fact that the mass of citric acid in the concentrated and diluted solution is the same. Then:

mass citric acid concentrated solution = mass citric acid in dilute solution

mass of citric acid = concentration · volume

Then:

initial concentration · volume = final concentration  · volume

12% · 4 cups = 5% · volume

volume = 12% · 4 cups / 5% = 9.6 cups

The final volume of the solution at 5% will be 9.6 cups. So Marta will need 9.6 cups - 4 cups = 5.6 cups water

it means there are 3 atoms of oxygen

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.