Answer:
41.9(w/w) %
Explanation:
Based on the reaction:
Na₂C₂O₄(s) + 2HCl(aq) → H₂C₂O₄(aq) + 2NaCl(aq)
<em>Where 1 mole of sodium oxalate reacts with 2 moles of HCl</em>
Moles of HCl solution to reach end point are:
44.15mL = 0.04415L ₓ (0.250mol / L) = 0.01104 moles of HCl
As 2 moles of HCl reacts per mole of Na₂C₂O₄:
0.01104mol HCl ₓ (1 mol Na₂C₂O₄ / 2 mol HCl) = <em>5.519x10⁻³ moles Na₂C₂O₄</em> are in the sample.
Molar mass of Na₂C₂O₄ is 134g/mol; thus, mass of 5.519x10⁻³ moles Na₂C₂O₄ is:
5.519x10⁻³ moles Na₂C₂O₄ ₓ (134g / mol) = <em>0.740g of Na₂C₂O₄</em> in the sample.
Thus, percent by mass of sodium oxalate in the sample is:
0.740g of Na₂C₂O₄ / 1.766g ₓ 100 =
<h3>41.9(w/w) %</h3>
I think this is done to allow even distribution of temperature in all the regions of the calorimeter. That is to make sure that there are no hot or cold spots and also ensure that the measured temperature is the actual average temperature when the readings are taken by a thermometer.
Answer:
Exolaiend in explanation section
Explanation:
First of all, the automatic hammer is used to drive nails into tight spaces where where we can't get a sufficient striking force if we are to use a normal regular hammer in driving the nail.
So the nail to be driven is lifted out of rest(it's position). The energy here is gravitational potential energy.
Now, when it is driven into the tight spaces, the gravitational energy would be converted to kinetic energy due to the motion and speed involved.
The answer is B! Chromatography involves solvent separation on a solid medium. Distillation takes advantage of differences in boiling points. Evaporation removes a liquid from a solution to leave a solid material