Students working in lab use 52.3g of CaCl2 to make a solution. When the solution is brought to a final volume of 800. mL, what is the concentration?

A. 0.139 M
B. 0.153 M
C. 0.588 M
D. 0.632 M

The answer is C: .588 M

Explanation:

[CaCl2] = mols CaCl2/Liters of solution

molar mass of CaCl2 = 110.98 g/ 1 mole   (from periodic table)

800 mL/1000 mL = .8 Liters of solution

1)

52.3g CaCl2/ 110.98g = .47 mole

2)

.47 mole/.8 L = .589 M

So the answer is C

im not exactly sure but i think its b!

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.