4) the ice has to be heated up to above 0c first, as it is continuing to cool the water back toward 0c
5) 0.0338 kcal
(33.8/1000)
6) 1.2506 kcal
((33.8*37.0)/1000)
Answer: Event 1 is an example of a physical change and Event 2 is an example of a chemical change.
Explanation: Physical change is one in which there is no change in chemical composition of the substance. There is only a change in phase change.
Chemical change is a change in which there is a change in chemical composition and there might or might not be a phase change.
On Boiling, the water molecules remain bonded in the same form and only covert from liquid to gaseous form, thus is a physical change.
On Rusting of iron nail, the iron changes to iron oxide by combining with oxygen, there is a rearrangement of atoms and thus is a chemical change.

Answer : The correct option is, (C) 2, 4 and 5.
Explanation :
Combustion reaction : It is a type of reaction in which a hydrocarbon react with an oxygen molecule to give carbon dioxide, water as a product.
For example : Methane react with oxygen to give carbon dioxide and water.

In the given list of chemical substances,
are in oxide form. They can not be both reactant and product of a single combustion reaction.
In the given list,
is the only hydrocarbon which shows a combustion reaction. That means
react with
to give
and
as a product.
The balanced combustion reaction of
is,

Therefore, the correct answer is, (C) 2, 4, and 5.
Answer:
= konstanta produk kelarutan
= kation dalam larutan berair
= anion dalam larutan berair
= konsentrasi relatif a dan b
DARI WEB
Divide the mass of the compound by the mass of the solvent and then multiply by 100 g to calculate the solubility in g/100g . Solubility of NaNO3=21.9g or NaNO3 x 100 g/ 25 g =87.6. Calculate the molar mass of the dissolved compound as the sum of mass of all atoms in the molecule.