How many grams of nacl should be added to 250 grams of waterto
make a 0.40 m solutions?

Answer : The mass of NaCl added should be, 5.85 grams.

Explanation : Given,

Mass of = 250 g

Molality of solution = 0.40 mol/kg

Molar mass of = 58.5 g/mole

Molality : It is defined as the number of moles of solute present in one kilogram of solvent.

Formula used :

Now put all the given values in this formula, we get:

Therefore, the mass of NaCl added should be, 5.85 grams.

gravity causes stares to cluster i think so

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j