You have a given amount of sodium chloride (3,0 grams) in a small test tube. Your task is to put, in a second empty test tube, as many ions of potassium and chloride as they are in the 3,0 grams of NaCl, and then to compare the actual volumes of the two amounts of solids. You have also alcohol, cylinder and pipette.
Ricevete 3,0 g di cloruro di sodio in una piccola provetta. L'obiettivo del gruppo è di introdurre in un'altra provetta tanti ioni potassio e cloruro quanti ve ne sono nella provetta con l'NaCl, quindi comparare i volumi effettivi delle due quantità di solidi. Avete a disposizione anche alcool, cilindro e pipetta graduati.
(Last point, 7, is unimportant because is not an operative step)
We have seen that the volume of potassium chloride is slightly higher that the sodium's volume.
1. Question 1
Why is the amount of KCl more than three grams?
because the atoms of K are bigger heavier than the atoms of sodium OK
2. Question 2
What data do you need to calculate volumes from masses, without measuring?
We need the density to calculate the volume. OK
3. Question 3
Why are the volumes of the two salts so different?
Because their molecular mass is different. NO. You should relate volumes of solids to the volume of their atoms or ions.
4. Question 4
Why is a lithium ion smaller than a sodium ion?
Answer 4
Because have a number of different atoms. No! a single ion is a single atom See pag 214 of your textbook (also to answer next question)
5. Question 5
Which is the largest between:
a) a bromide ion and a chloride ion
b) a cesium ion and a cesium atom
c) a sodium ion and a magnesium ion
d) a iodine atom and a iodide ion
e) an oxygen atom and a sulphur atom