10.1 Water Flashcards
What are 2 chemical tests for the presence of water? [2]
- anhydrous cobalt(II) chloride
- anhydrous copper(II) sulfate
What is produced when you add anhydrous copper(II) sulfate to water? [1]
produces hydrated copper(II) sulfate
What is produced when you add anhydrous cobalt(II) chloride to water? [1]
produces hydrated cobalt(II) chloride
What is the positive result of anhydrous copper(II) sulfate + water? [2]
anhydrous copper(II) sulfate turns from white to blue
What is the positive result of anhydrous cobalt(II) chloride + water? [2]
anhydrous cobalt(II) chloride turns blue to pink
When you go from anhydrous to hydrous, which type of chemical reaction is it? [1]
exothermic
When you go from hydrous to anhydrous, which type of chemical reaction is it and why? [2]
- endothermic
- since it needs energy to heat up
What does ⇌ stand for and what’s its meaning? [2]
- equilibrium
- if you heat it up, the water evaporates and it turns to the original colour again
How do we know the purity of water using the melting point? [1]
- if the water is impure the melting point decreases
How do we know the purity of water using the boiling point? [1]
- if the water is impure the boiling point increases
Why is distilled water used in practical chemistry instead of tap water? [1]
- it contains fewer chemical impurities
What are the key steps in the domestic water supply process? [7]
- screen
- coagulant
- sediment
- filter
- chlorine
- fluoride
- reservoir
What is the usage of sedimentation and filtration? [1]
to remove solids
What is the usage of carbon in the water supply process? [2]
- to remove tastes
- to remove odours
What is the usage of chlorination? [1]
to kill microbes (pathogens)
