A. Pyrite is an ore of gold and is used to jewelry making is a false statement
The correct answer is B. Platinum is the transition element among the choices. The elements belonging to this group are those having a partially filled d or f subshell. It usually refers to the d-block transition elements of the periodic table.
Answer:
CaCO₃ built up in hot water pipes
Explanation:
The hardness of water is classified as;
Permanent Hard Water:
In this the mineral content cannot be removed by boiling. This water contains mainly following,
Calcium Sulfate CaSO₄
Calcium Chloride CaCl₂
Magnesium Sulfate MgSO₄
Magnesium Chloride MgCl₂
These salts does not precipitate out on heating water.
Temporary Hard Water:
In this water the mineral content can be removed by boiling. This water contains mainly following,
Calcium Bicarbonate Ca(HCO₃)₂
Calcium Carbonate CaCO₃
Magnesium Bicarbonate Mg(HCO₃)₂
Magnesium Carbonate MgCO₃
These salts does not precipitate out on heating water. i.e.
Ca(HCO₃)₂ -------heat------> CaCO₃ + CO₂ + H₂O
The CaCO₃ are formed in the form of scales.
Result:
Hence, we can say that that CaCO₃ built up in hot water pipes.
Answer:
119 protons and 179 neutrons
Explanation:
Given an element of the form AB-298, we know that 298 is the mass, which means it's the sum of the number of protons and number of neutrons.
Look at the answer choices and find the one whose numbers add up to 298. Only C (119 protons and 179 neutrons) is correct because 119 + 179 = 298.
Hope this helps!
