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  Avui al laboratori hem estudiat el tir parabòlic que descriu un cigró en ser llençat amb una velocitat inicial desconeguda. A partir de les dades experimentals d'abast i d'angle inicial hem estat capaços de calcular la velocitat inicial del cigró en sortir de la cullera.  Hem fet servir una aplicació per tal de poder visualitzar els fotogrames de la gravació del moviment i així poder determinar amb precisió l'abast i el temps que triga el cigró a impactar amb la taula. També hem vist com afecta l'angle inicial en la distància horitzontal recorreguda pel cigró (abast). Aquestes són les dades que hem posat en comú: I aquesta és la fórmula que permet calcular la velocitat inicial en funció de l'abast (x en metres) i l'angle inicial (alfa en graus): 1. Quines conclusions pots treure de les dades experimentals obtingudes? 2. Quina és la velocitat inicial del cigró en els diferents casos que has estudiat? Els valors de velocitat que has obtingut en els diferents exp...

Paper chromatography is the technique used to separate the compounds of a mixture taking the advantage of their different polarity. The following pictures show how the solvent (mobile phase) carries the pigments through the stationary phase (paper). The retention factor can be calculated dividing the distance travelled by the spots (a) by the distance travelled by the solvent (b). The following picture shows the chromatogram with two spots (green and yellow) corresponding to chlorophyll and xanthophyll compounds with their retention factors depending on their affinity to the mobile phase.  Read the text  The colour of leaves and answer the qüestions: Which are the main pigments present in the leaves? Which pigment is the responsible for the green colour of leaves? Which pigment is the responsible for the yellow colour of leaves? Which pigment is the responsible for the brown colour of leaves? Which are the two parts of chlorophyll molecule? Which part of the structure of the...

Today we have performed the distillation of mint leaves using ethanol as a solvent and we have obtained a green solution in the distillation flask. This chlorophyll solution wil l be separated by paper chromatography with the aim of identify its pigments. We will also try to decolorize the solution again using active carbon since the first attempt was not succesful. Rosemary leaves were also been infused during 15 days in order to obtain a concentrate solution of essential oil.  The leaves have been grinded with a mortar.                                            Wich is the active ingredient of mint smell?  Wich is the chemical formula of this ingredient? Wich is the active ingredient of rosemary smell?  Wich is the chemical formula of this ingredient? Active carbon is an adsorbent. Explain how you could impr ove the  Adsorption   process made in the ...