Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepressant medication fluoxetine (Prozac) and the material PTFE (Teflon).
Hi there!
p = e-3
s = f-1
f = i-7
d = g-5
Hope that helps!
Brady
Answer:
OPTION (A) : Testing a rock sample for gold content
Explanation:
For testing a rock sample of gold content you will need a Chemist. To test the material, the sample is rubbed on black stone which will leave a mark on the stone. This mark is tested by applying aqua fortis i.e nitric acid on the mark. If the mark gets dissolve then the material is not gold. If the mark sustain the it is further tested by applying aqua regia i.e nitric acid and hydrochloric acid which will prove the sample is of gold if it gets dissolve on using hydrochloric acid. The purity of the sample can be checked by differing the concentration of the aqua regia and comparing it with the gold material of the known purity.
If water loses heat then it will become cold and as the water becomes cold it starts forming these little bubbles around the glass. If you want extra information search up *Why are there bubbles in my water?* and it will give you the information right on the page if you're using a Google browser! Hint Hint! it has to do with nitrogen!
~Pinkachumoo
Which you the best!
