Answer:
A) Sample B has more calcium carbonate molecules
Explanation:
M = Molar mass of calcium carbonate = 100.0869 g/mol
= Avogadro's number = 
For the 4.12 g sample
Moles of a substance is given by

Number of molecules is given by

For the 19.37 g sample

Number of molecules is given by


So, sample B has more calcium carbonate molecules.
The ratio of the elements of carbon, oxygen, calcium atoms, ions, has to be same in both the samples otherwise the samples cannot be considered as calcium carbonate. Same is applicable for impurities. If there are impurites then the sample cannot be considered as calcium carbonate.
Answer:
Option C. hydroxide ions (OH-).
Explanation:
A base is a substance which dissolves in water to produce hydroxide ion (OH-) as the only negative ion. It therefore means that a base contains more hydroxide ions (OH-).
Answer: 123 g
Explanation: Q =It = nzF. For Ca^2+ z= 2, t = 5.5 x 3600 s and I = 30.0
And F= 96485 As/mol
Amount of moles is n = It /zF = 3.078 mol , multiply with atomic mass 40.08 g/mol
Answer:
A) 8.51 × 10²⁴
Explanation:
1. Gather all the information
2H₂S + SO₂ ⟶ 3S + 2H₂O
n/mol: 9.42
2. Calculate the moles of S atoms
The molar ratio is 3 mol S:2 mol H₂S

3. Calculate the atoms of S
