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Found 7 results

  1. Hey guys, so I am doing my Chemistry IA on enthalpy changes of alcohol.. and so I was like half done my experiment (collected data) when I came across an IA topic researching exactly what I am researching, like my introduction, background info are different but our methodology to carry out the experiment is the same and data processing method is the same.... I was wondering is it okay to carry on? I still have my own original data, original background information, original introduction...its just our method to carry out the experiment and the way to find out the calculations is the same....... shall I carry on with my IA? please do let me know if you have any input on this, thanks.
  2. Hey guys, I'm doing a lab in my SL Chemistry class called the Heat of Reaction/ Hess's Law lab. Basically we used a polystyrene cup as our calorimeter, and performed three reactions. Calculations were made to determine molar enthalpy. The target reaction was reaction 3 (-54.3 kJ/mol) , and reaction 1 and 2 were used to calculate the molar enthalpy of the target reaction (-50.8 kJ/mol). We then compared the values. What are some limitations of this lab? I'm really stuck. Thanks in advance! (below I have posted the entire procedure) Pour 200 mL of water into a polystyrene cup and record the temperature. Measure out 4 grams of sodium hydroxide pellets and record the mass. Pour the sodium hydroxide into the water and stir until dissolved. Record the temperature of the solution. Discard. Pour 200 mL of 0.50M hydrogen chloride solution into a polystyrene cup and record the temperature. Measure out 4 grams of sodium hydroxide pellets and record the mass. Pour the sodium hydroxide into the hydrogen chloride and stir until dissolved. Record the temperature of the solution. Discard. Measure 100 mL of 1.0M hydrogen chloride solution into a polystyrene cup. Measure 100 mL of 1.0M sodium hydroxide solution into a 250 mL beaker. Record the temperature of both solutions. Pour the sodium hydroxide into the hydrogen chloride. Record the temperature of the solution. Discard.
  3. So we have a lab on the heat of neutralization of NaOH and HCl given: mass of NaOH = 48.01 g Volume of NaOH = 1000.00 mL Amount of HCl = 83.3 mL of 12.0 M of HCl in 1000.00 mL solution And we found the initial temperature, final temperature Temp initial = 21.5 degrees C Temp final = 25.0 degrees C And we have to find the heat of neutralization using this equation: ΔHθneutralization = (-specific heat capacity of liquid water x mass (acid solution + base solution) x change in temp) / mole of limiting base or acid And I should be getting an enthalpy of around -58 -ish but I'm wayyy off. Help please!! P.S. I'm not that great at writing chem labs... :/
  4. Aim: the aim of this experiment is to determine the difference of enthalpy changes of neutralization reactions of strong acids and weak acids. So my strong acids were hydrochloric and nitric and weak were citric and ethanoic. Most of them are within literature value range or under which is obviously attributed to heat loss. However my ethanoic ended up being a lot higher than the others. What kind of error is that? What would be a suitable improvement? What other errors can I mention beyond more insulation, trials and accounting for the specific heat capacities of my equipment (PS what's an improvement to this one?).
  5. There are two beakers. Beaker A has 100cm^3 of 1.0 M of HCL acid in it and Beaker B has 200cm^3 of 0.5 M of HCL acid in it. Both beakers have the same amount of magnesium put into them. Will the maximum temperature of A be higher than B? Are the maximum temperatures of A and B equal? Will the rate of increasing temperature be the same for A and B?
  6. Hello everyone! I have problem with my Design project in IB Chemistry HL. My research question is: how does the concentration affect the value of experimentally determined enthalpy? I have collected the necessary data, I've created a graph of temperature change versus concentration - it shown the positive linear correlation. After that I have plotted the graph of enthalpy change versus number of moles. As we know, enthalpy is amount of heat changed per mole of a substance. It does not change with the number of moles, it is a constant. Thus, the graph should look in the form y=c, where c=const. Now my question is: How to calculate the uncertainty of that graph? Should I use the equation used in physics that applies for linear graphs: (gradient of f(max)-gradient of f(min)/2? Or should i use sth else? Any ideas? Are we, as the students of IB Chemistry, supposed to calculate the uncertainties of graphs? I've seen a Design Lab Report from chemistry in which the author did not calculate the line of best fit. Neitherless, he got almost maximum points, by the teacher and moderator.
  7. So my Group 4 project is thermal energy and all I have been able to come up are the ideas all my physics and chemistry teachers call "simple". That's a bad thing so I need to come up with an idea for my Group 4 Project about thermal energy in chemistry or physics. This is my first time doing the G4 project and I need major help coming up with an idea because the topic is kind of to think about. Thanks!
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