<span>solution of KI becomes saturated at 10 degrees when around 135-138g KI are added to 100 g of water, so it should be still unsaturated, A. unsaturated (although it is very close to saturation)</span>
Half-life of a radioactive substance is the time required to reduce the amount of substance to half of its initial amount.
In present case, half-life is material is given as 1000 years and initial amount of material is given as 400 kg
Answer 1) Since, half-life of radio-active substance is 1000 years, therefore after 1st half life, amount of the material will be left to half the initial amount. Hence, amount of substance left after 1000 years = 400/2 = 200 kg.
Answer 2) For 2000 years, radioactive material has crossed 2 times the half life. Therefore , amount of the material will be left to 1/4 the initial amount. Hence, amount of substance left after 2000 years = 400/4 = 100 kg.
Answer 3) For 4000 years, radioactive material has crossed 4 times the half life. Therefore , amount of the material will be left to 1/16 the initial amount. Hence, amount of substance left after 4000 years = 400/16 = 25 kg.
Answer:
Explanation:
I’m 99.9% sure that it’s an element because it can’t be broken down any more than it already is.
Chemical change. Compounds and molecules in the milk are reacting with the air and breaking down and forming new molecules.
Answer : The final temperature of the solution in the calorimeter is, 
Explanation :
First we have to calculate the heat produced.
where,
= enthalpy change = -44.5 kJ/mol
q = heat released = ?
m = mass of 
= 1.52 g
Molar mass of = 40 g/mol
Now put all the given values in the above formula, we get:
Now we have to calculate the final temperature of solution in the calorimeter.
where,
q = heat produced = 1.691 kJ = 1691 J
m = mass of solution = 1.52 + 35.5 = 37.02 g
c = specific heat capacity of water = 
= initial temperature = 
= final temperature = ?
Now put all the given values in the above formula, we get:
Thus, the final temperature of the solution in the calorimeter is,
