Hi, here is a basic summary of what we did in a lab; there were 3 reactions: The procedure: Reaction 1: Solid sodium hydroxide dissolves in water to form an aqueous solution of ions. NaOH(s)-> Na+(aq) + OH-(aq) ΔH1=-34.121kJ Reaction 2: Solid sodium hydroxide reacts with an aqueous solution of HCl to form water and an aqueous solution of sodium chloride. NaOH(s) + H+(aq) + Cl-(aq) -> H2O + Na+(aq) + Cl-(aq) ΔH2=-83.602kJ Reaction 3: An aqueous solution of sodium hydroxide reacts with an aqueous solution of HCl to form water an an aqueous solution of sodium chloride. H+(aq) + OH-(aq) + Na+(aq) + Cl-(aq) -> H2O + Na+(aq) + Cl-(aq) ΔH3= -50.2kJ The ΔH values were calculated by dividing the heat gained by the number of moles (each reaction had 0.05moles of NaOH) The problem: Net ionic equations for reaction 2 & 3: 2: NaOH(s) + H+(aq) -> H2O + Na+(aq) 3: H+(aq) + OH-(aq) -> H2O i) In reaction 1, ΔH1 represents the heat evolved as solid NaOH dissolves. Look at the net ionic equations for reactions 2 and 3 and make similar statements as to what ΔH2 and ΔH3 represent. ii) Compare ΔH2 with (ΔH1 + ΔH3). Explain in sentences the similarity between these two values by using your answer to #5 above. Attempt at answering: i) Firstly, ΔH2 represents the heat evolved as the hydrogen ion displaces the sodium ion, creating a single displacement reaction. ΔH3 represents the heat evolved as the hydrogen and hydroxide ion form water via a neutralization reaction. ii) ΔH2 is equal to (or supposed to be, this is a source of error while calculating) (ΔH1 + ΔH3). The similarity between these two values is that .. (this is where I get confused!)
Source https://www.physicsforums.com/threads/calorimetry-help-chemistry.399653/
The matter wasn't destroyed because albert einsteins theory of the black hole says that matter cannot be destroyed if it is burned into the same color of a black hole. this eqation proves my thesis:
²²↑↑Ф
Answer:
0.007 mol
Explanation:
We can solve this problem using the ideal gas law:
PV = nRT
where P is the total pressure, V is the volume, R the gas constant, T is the temperature and n is the number of moles we are seeking.
Keep in mind that when we collect a gas over water we have to correct for the vapor pressure of water at the temperature in the experiment.
Ptotal = PH₂O + PO₂ ⇒ PO₂ = Ptotal - PH₂O
Since R constant has unit of Latm/Kmol we have to convert to the proper unit the volume and temperature.
P H₂O = 23.8 mmHg x 1 atm/760 mmHg = 0.031 atm
V = 1750 mL x 1 L/ 1000 mL = 0.175 L
T = (25 + 273) K = 298 K
PO₂ = 1 atm - 0.031 atm = 0.969 atm
n = PV/RT = 0.969 atm x 0.1750 L / (0.08205 Latm/Kmol x 298 K)
n = 0.007 mol
Answer: Undecane, C11H24 is a liquid hydrocarbon from the alkane homologue ( family ).
Explanation:
All hydrocarbons burn in air to release H20 and CO2.
Combustion of hydrocarbons thus increases the percentage of CO2 present in the atmosphere which is not so good as CO2 is a greenhouse gas. Greenhouse gases produce the greenhouse effect. The green house effect is the warming effect produced when gases present in the atmosphere allow and retain the radiation from the sun to the earth. Examples of greenhouse gases are CO2, CH4, SO3, NO, CFCs. The greenhouse effect leads to an increase in the temperature of the earth subsequently leading to (I) melting of large amounts of ice at the poles causing flooding. (II) rapid evaporation of water from Earth’s surface. (III) decrease in crop yield.
Also, high concentration CFCs ( chlorofluorocarbons ), as widely used in aerosols, coolants and packaging foams, in the atmosphere depletes the ozone layer leading to global warming. In 1996 an international agreement was reached for a complete ban of CFCs and more countries are now going Green ( using alternative energy sources ) so as to minimize emissions of these greenhouse gases
