A solution is made by dissolving 14.57 g of sodium bromide (NaBr) in
415 g of water.
What is the molality of the solution?
[?] m NaBr
Molar mass of NaBr: 102.89 g/mol

0.342 m

Explanation:

From the question given above, the following data were obtained:

Mass of NaBr = 14.57 g

Mass of water = 415 g

Molar mass of NaBr = 102.89 g/mol

Molality of NaBr =?

Next, we shall determine the number of mole in 14.57 g of NaBr. This can be obtained as follow:

Mass of NaBr = 14.57 g

Molar mass of NaBr = 102.89 g/mol

Mole of NaBr =?

Mole = mass / molar mass

Mole of NaBr = 14.57 / 102.89

Mole of NaBr = 0.142 mole

Next, we shall convert 415 g of water to kg. This can be obtained as follow:

1000 g = 1 Kg

Therefore,

415 g = 415 g × 1 Kg / 1000 g

415 g = 0.415 Kg

Thus, 415 g is equivalent to 0.415 Kg.

Finally, we shall determine Molality of the solution as follow:

Mole of NaBr = 0.142 mole

Mass of water = 0.415 Kg

Molality of NaBr =?

Molality = mole / mass of water in Kg

Molality of NaBr = 0.142 / 0.415

Molality of NaBr = 0.342 m

Therefore, the molality of NaBr solution is 0.342 m.

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.

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