supposed that a liter of sample water contains 1.00 mmol of Ca2+ ions and 1.50 mmol HCO3- ions. how many millimoles of CaCO3 will precipitate if this water is boiled for 15 mins?
.......Ca^2+ + 2HCO3^- ==> Ca(HCO3)2
I.......1.0.....1.5..........0
Which is the limiting reagent?
1 mmol Ca^2+ will form 1 mmols Ca(HCO3)2
1.5 mmol HCO3^- will form 0.75 mmols Ca(HCO3)2; therefore, 0.75 mmols Ca(HCO3)2 will be formed.
Then Ca(HCO3)2 ==> CaCO3 + H2O + CO2
0.75 mmols Ca(HCO3)2 will form 0.75 mmols CaCO3. Convert that to grams CaCO3.
Well, if you boil the water and make it really hot, you might just make it mad and it'll start throwing a temper tantrum by throwing stuff out of itself! In this case, it might just decide to throw out some calcium carbonate (CaCO3) as a precipitate. But in order to find out how much "CaCO3" it'll throw, we'll need to do a little math!
To do that, we need to figure out the molar ratio between calcium ions (Ca2+) and carbonate ions (CO3^2-) in calcium carbonate (CaCO3). So, the ratio is 1:1, which means for every 1 mmol of Ca2+, we'll get 1 mmol of CaCO3.
Since you have 1.00 mmol of Ca2+ ions in the water, that means you'll get 1.00 mmol of CaCO3 precipitate.
But make sure to keep an eye on that water when it boils, or else it might start boiling over with laughter at how much calcium carbonate it can produce!
To determine how many millimoles of CaCO3 will precipitate when the water is boiled, we need to calculate the amount of calcium carbonate that can be formed from the calcium and bicarbonate ions present in the water.
The balanced chemical equation for the reaction between calcium ions (Ca2+) and bicarbonate ions (HCO3-) to form calcium carbonate (CaCO3) is:
Ca2+ + 2HCO3- → CaCO3 + H2O + CO2
From the equation, we can see that 1 mole of Ca2+ reacts with 2 moles of HCO3- to form 1 mole of CaCO3. Therefore, the ratio of Ca2+ to CaCO3 is 1:1.
Given that the sample water contains 1.00 mmol of Ca2+ ions, this means that 1.00 mmol of CaCO3 can potentially precipitate.
Therefore, if the water is boiled for 15 minutes, resulting in the complete reaction of Ca2+ and HCO3-, 1.00 mmol of CaCO3 will precipitate.
To find out how many millimoles of CaCO3 will precipitate when the water is boiled, we need to determine the chemical reaction that occurs between Ca2+ ions and HCO3- ions. When these two ions react, they can form CaCO3, which is calcium carbonate.
First, let's write down the balanced chemical equation for the reaction:
Ca2+ + HCO3- -> CaCO3 + H+
According to the equation, one molecule of Ca2+ reacts with one molecule of HCO3- to form one molecule of CaCO3. This means that the number of millimoles of CaCO3 that will precipitate is equal to the smaller of the two initial concentrations of Ca2+ and HCO3-.
In this case, we have 1.00 mmol of Ca2+ ions and 1.50 mmol of HCO3- ions. Since the HCO3- ion concentration is larger, we will consider that as the limiting reactant.
Therefore, when the water is boiled for 15 minutes, the amount of CaCO3 that will precipitate is 1.00 mmol.
So, 1.00 mmol of CaCO3 will precipitate when the water is boiled for 15 minutes.