Enthalpy is the change in energy. A cold pack will react endothermically and enthalpy will be positive and a heat pack will have negative enthalpy. You cannot determine which has more change in enthalpy unless you measure the temperature change. Eg. a heat pack went from 25c to 35c will have greater change in enthalpy then a cold pack going from 25 to 20c because the net temperature difference is greater
Answer:
[NH₃] → 3.24 M
Explanation:
Our solute: Ammonia
Our solvent: Water
Solution's mass = Mass of solute + Mass of solvent
Solution's mass = 15 g + 250 g = 265g
We use density to determine, the volume.
D = mass /volume → Volume = m / D → 265 g /0.974 g/mL = 272.07 mL.
We convert the mL to L → 272.07 mL . 1L /1000mL = 0.27207 L
To determine molarity we need the moles of solute in 1 L of solution.
Moles of solute are: 15g / 17g/mol = 0.882 moles
[NH₃] = 0.882mol /0.27207 L → 3.24 M
The difference between a substance and a mixture is that a substance is one of a kind, a material of the same composition throughout, on the contrary, a mixture is one or more different substances brought together and mixed together without changing the nature of each single substance.
One way to test it is to take two substances like sand and table salt. They should each be in granular form and in adequate amount to mix. Neither substance has changed after mixing the two. Even though it may not be easy or convenient to accomplish, each substance could be separated out from the mixture.
When it comes to two substances in lump form, it would not be a mixture when one lump is positioned next to the other lump because there are not enough pieces to combine.
However, there could be a mixture of three substances, like sand, table salt and graphite powder and there could be a mixture with four substances, etc., ad infinitum.
Mixtures are of solid substances in general. On the other hand, one starts referring to solutions when liquids are involved. Gases can be a mixture like for example, air is a mixture with nitrogen, oxygen, argon, etc.
Let us see the structure of ascorbic acid
As shown there is no COOH group however the OH group can lose a proton and forms conjugate base
The conjugate base formed is stabilized due to resonance
More the stability of conjugate base more the strength of acid
Hence ascorbic acid behaves as an acid
