lab final - Experiment 1 Lowering of the freezing point =...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Experiment 1 Lowering of the freezing point = constant x molar concentration of solute Use a coffee cup calorimeter H 2 O(l) H 2 O (s) (freezing) is exothermic Bonds are being made, producing energy and this energy is released from the water in the form of heat, which is why the temperature drops H 2 O(s) H 2 O(l) (melting) is endothermic Bonds are being broken so energy needs to be put into the system2 Solid salt dissolving in water: close to thermoneutral because the temperature stays the same. The energy produced by the bonds that are being made is close to the same amount of energy needed for the bonds that are being broken. The freezing point of NaCl is lower than that of NH 4 Cl, so its concentration is higher than that of NH 4 Cl. Because NaCl is a “stronger” salt, or dissociates better Experiment 9 Redox Reactions 1) Zn + HCl Zn(s) Zn 2+ + 2e- 2H + + 2e- H 2 (g) Many gas bubbles are released. Gives off heat, exothermic 2) Cu + HCl No reaction occurred. 3) Zn
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/07/2008 for the course CHEM 120 taught by Professor Dr.wagner during the Spring '07 term at Pittsburgh.

Page1 / 3

lab final - Experiment 1 Lowering of the freezing point =...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online