1) Calcium carbonate comprises 40.0% calcium by weight.
M(CaCO₃)=100.1 g/mol
M(Ca)=40.1 g/mol
w(Ca)=40.1/100.1=0.400 (which is 40.0%)!
2) The mass fraction mentioned is superfluous information.
3) The resulting solution is:
m(Ca)=1.2 g
m(CaCO₃)=M(CaCO₃)*m(Ca)/M(Ca)
m(CaCO₃)=100.1g/mol*1.2g/40.1g/mol=3.0 g
Greetings!
The result is:
The new volume is: 
Rationale:
Because the temperature remains constant, we can apply Boyle's Law to solve this issue.
Boyle's Law stipulates that:
Where,
P is the gas's pressure.
V is the gas's volume.
According to the information provided:
Let's put the values into the equation:
Consequently, the new volume is:
Wishing you a lovely day!
I predict that there will be an increase in the seconds recorded in the time column. This is because, as more water is mixed with sodium thiosulfate, its concentration diminishes in each flask. Additionally, a lower concentration results in a slower reaction rate since fewer molecules of sodium thiosulfate means there are less frequent collisions with sulfuric acid. With fewer collisions occurring in the reaction, it takes a longer time for the reaction to complete, leading to increased time when sodium thiosulfate is diluted.
Explanation:
I can confirm that this explanation is accurate.
