You want to make 100 ml of a 2.5 m stock solution of calcium chloride (molecular weight 110.98 g/mol). how many grams of calcium chloride do you need to weigh out in order to make this solution? round your answer to the nearest tenth of a gram.

27.7 g

Explanation:

To solve this problem we use the definition of molarity:

From the problem we're given M = 2.5 M and volume = 0.100 L. We use the above formula and calculate the required moles of calcium chloride (CaCl₂):

Finally we use the molecular weight of calcium chloride to calculate the required mass:

Rounding to the nearest tenth of a gram the answer is 27.7 g.

- lead + phosphoric acid = hydrogen + lead(ii) phosphate

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.