A) a water sample (density=1.00g/ml, s=0.28g/kg) contains ca(2+) at a concentration of 42 mg/kg. calculate the molarity of the ion.

Answer : The molarity of the ion is

Explanation : Given,

Density of sample = 1.00 g/mL

Concentration of = 42 mg/kg

First we have to calculate the volume of sample.

Let us assume that the mass of sample be 1 kg or 1000 g.

       (1 L = 1000 mL)

Now we have to calculate the moles of

As we are given that,

Mass of in 1 kg of sample = 42 mg = 0.042 g

Molar mass of Ca = 40 g/mole

Now we have to calculate the molarity of the ion.

Therefore, the molarity of the ion is

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.

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.