Answer:
The correct answer is - B. dissolving → evaporation filtration → crystallisation
Explanation:
The method of the preparation of a pure sample of copper(II) sulfate from dilute sulfuric acid and copper II oxide is given as follows:
step 1. Adding dilute sulfuric acid into a beaker. Using bunsen burner heat the beaker.
step 2. Adding the copper (II) oxide into the beaker and give it a little time at a time to the warm dilute sulfuric acid and stir
step 3. Filtering the mixture into an evaporating vessel to remove the excess copper (II) oxide and water from the filtrate.
Step 4. leave the rest filtrate to crystallize.
Copper (II) Oxide {CuO (s)} + Dilute Sulfuric Acid {H2SO4 (aq)} → Copper (II) Sulphate {CuSO4 (s)} + Water {H2O}
Chlorine is a halogen and is very reactive and unstable. If released in an elemental form (Cl2), it would react with other substances immediately. However, <span>chlorofluorocarbons (CFCs) which contain chlorine are unreactive and when released they eventually end up in the upper atmosphere still "intact". In the upper atmosphere, sunlight is more intense and is able to break apart CFC, releasing the highly reactive chlorine which in turns destroys ozone which is more abundant in the upper atmosphere (stratosphere). </span>
B is correct
salt lowers the freezing point of water (colligative property) by lowering the interaction and intermolecular forces between water molecules
B, the height above or below sea level
Answer:
Relative atomic mass or atomic weight is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a given sample to the atomic mass constant. The atomic mass constant is defined as being 1/12 of the mass of a carbon-12 atom.
