Asolution is prepared by dissolving 20 g naoh (fw = 400 g/mol) to 255 ml of solution. if the density of the solution is 1.15 gim, what is the mass percent naoh in the solution? 0.68% 0.78% 0.90% 6.8% 78% nt navigator

6.82% is the mass percent NaOH in the solution.

Explanation:

Mass of the solute that is NaOH = m = 20 g

Mass of the solution = M

Volume of the solution = V = 255 mL

Density of the solution = d = 1.15 g/mL

M = 293.25 g

Mass percentage of solute :(w/w)%

6.82% is the mass percent NaOH in the solution.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.