<span>Answer:
he strong acid- strong base reaction should give more energy.
So why is the heat of neutralization (enthalpy) of a strong acid such as HCl with a strong base like NaOH more than the heat of neutralization of a weak acid, such as acetic acid with NaOH?
The enthalpy of neutralization of an acid by a base is defined as heat change when one gram equivalent of acid is neutralized by a base ,the reaction being carried out in dilute aqueous solution ... enthalpy of neutralization of base by an acid is defined in a similar manner...
for example when 1 gram equivalent of HCl is neutralized with NaOH 57.1 kj of heat is produced .. HCl (aq) + NaOH (aq)----> NaCl (aq) + H2O (l)... H = -57.1 kj/mole
hence enthalpy of neutralization of HCl with NaOH is 57.1 kj enthalpy of neutralization of any strong acid (like HCl,HNO3,H2SO4) with a strong base (like LiOH,NaOH,KOH) or vice versa is always the same i.e. 57.1 kj...this is because strong acids ,strong bases and salt that they form are all completely ionized in dilute aqueous solutions ...thus the reaction between any strong acid and strong base for example in the above case may be written as :
NaOH (aq) + HCl(aq) -----> NaCl (aq) + H2O (l)... H = -57.1 kj/mole
they will dissociate as :
Na(+) (aq) + OH(-) (aq) + H(+) (aq) + Cl(-) (aq) ---> Na(+) (aq) + Cl(-) (aq) + H2O (l)
common ions will cancel out..
H(+) (aq) + OH(-) (aq) ----> H2O (l)
thus neutralization is simply a reaction between H(+) ions given by acids and OH(-) ions given by base to form one mole of H2O.....since strong acid and strong base completely ionize in aqueous solution number of H(+) and OH(-) produced by 1 gram equivalent of strong acid and strong base is always the same ...hence enthalpy of neutralization between a strong acid and strong base is always constant...
if either the acid or base or both are weak the enthalpy of neutralization is less than 57.1 kj ...the reason for this behaviour can be explained by considering the neutralization between a strong base like NaOH and weak acid like acetic acid.. now acetic acid ionizes to a small extent whereas NaOH ionizes completely as :
NaOH (aq) ----> Na(+) (aq) + OH(-) (aq)
CH3COOH (aq)<--------> CH3COO(-)(aq) + H(+)(aq)
(an equilibrium) when H(+) given by acid combine with OH(-) given by base the equilibrium shifts to right (in accordance with Le Chatelier's principle) ,so more of acetic acid dissociates ...a part of heat produced during combination of H(+) and OH(-) ions is used up for complete dissociation of acetic acid ...the heat thus used up is called enthalpy of dissociation or enthalpy of ionization ..it is 1.9 kj for acetic acid...hence net heat evolved in above reaction is 57.1 - 1. 9 = 55.2 kj ...which less than that evolved in strong base and strong acid reaction.</span>
Boric acid, H3BO3, in aqueous solution would only give out one H+ ion. As it is also produce OH ion and by hydrolysis it produces one proton. <span>All the boron compounds (BX3) are having only 6 valence electrons in it and should follow the octet rule by taking another electron.</span>
B(OH)3 + 2 H2O → B(OH)4− + H3O
<span>Safety glasses are to be worn whenever working with acids, bases, or any flammable materials. Let the instructor know immediately about any glassware breakage or chemical spills that may occur so that proper cleanup procedures can be instituted.Use pipet fillers whenever pipeting any fluid.Whenever working with acids or bases, have the chemicals available at your work station, do not carry pipets with fluid across the room.When diluting acids, pour the acid into the water, NOT water into acid as this may cause spattering of the acid.When acid is mixed with another reagent, an exothermic reaction may occur which heats up the container, This is natural, so do not panic and spill contents.All volatile materials must be handled in a hood with the exhaust fan on.When refluxing any solutions, perform this operation under a hood, and use boiling beads in the reflux vessel to prevent any excessive "bumping" and possible glass breakage.Use heat-resistant gloves and/or tongs when handling hot glassware, chinaware, etc.Use plastic gloves when handling any hazardous materials to prevent skin contact.Label and date all chemical mixtures that are made up and kept for future use.Do not store basic solutions in glass containers with glass stoppers, use plastic or rubber stoppers.Dispose of all used solutions in an approved manner as directed by the instructor.Empty all used inoculated bacteriological media from test tubes or dishes into a designated container so that it may be sterilized before disposal.Before leaving, turn off all power and heat to the apparatus you have used, or place in the standby mode.Clean all spatulas, glassware, and dishes after use and before storage to prevent contamination.<span>Return all chemicals you are using to their proper storage space.Be familiar with the use of the eye-wash, the laboratory shower (if equipped), and the first-aid kit if they are needed at any time.</span></span>
Combustion. You said CH4 'burns' in the question which is another word for combustion.
Answer:
A. Hydrogen cans oxygen are reactants
Explanation:
Oxygen has a charge of -2. Hydrogen has a charge of +1. So it takes two hydrogens to balange the one oxygen hence the H20. So the reaction is balanced, and H20 is indeed made up of 1 oxygen and 2 hydrogen atoms. The equation 2 hydrogen + 1 oxygen (<---reactants) = Water (<--product) So hence Hydrogen cans oxygen is not a true statement. If cans is a misspelling then C would be your answer.
Hope that helped
