A mixture of BaCl2.2H2O (FM244.26) and K2SO4 (FM 174.26) is heated at 160C for an hour, causing the water molecules to leave. A sample originally weighing 2.0027 g weighed 1.9021 g after heating. Calculate the mass percent K2SO4 in the sample.
In a previous practice example, I had to find the weight percent of Ba, K, and Cl (K2S04 now replacing KCl). So how would I go about finding mass % of K2S04? Would I have to calculate weight percent of Ba, K2 and SO4 as well or is there something else?
Thank you.
No you need not go through that. The easy way is to determine the H2O lost (as in the previous problem), convert that to grams BaCl2.2H2O, then subtract the mass of BaCl2.2H2O from the total mass to find mass K2SO4.
Then %K2SO4 = (mass K2SO4/mass sample)*100 = ?
To calculate the mass percent of K2SO4 in the sample, you do not need to calculate the weight percent of Ba, K2, and SO4 this time. You can directly determine the mass percent of K2SO4 using the information provided.
Let's break down the steps to find the mass percent of K2SO4:
1. Determine the initial mass of the mixture.
The initial mass of the mixture is given as 2.0027 g.
2. Determine the final mass of the mixture after heating.
The final mass of the mixture is given as 1.9021 g.
3. Calculate the mass of water lost during heating.
The mass of water lost is the difference between the initial and final masses: 2.0027 g - 1.9021 g = 0.1006 g.
4. Calculate the mass of the anhydrous salt remaining.
The mass of the anhydrous salt remaining is the final mass minus the mass of water lost: 1.9021 g - 0.1006 g = 1.8015 g.
5. Determine the mass percent of K2SO4 in the sample.
Mass percent is calculated by dividing the mass of the component (K2SO4) by the total mass of the sample and multiplying by 100%.
Mass percent K2SO4 = (mass of K2SO4 / total mass of sample) * 100%
Since K2SO4 is the anhydrous salt remaining after heating, the mass percent of K2SO4 is:
Mass percent K2SO4 = (1.8015 g / 1.9021 g) * 100%
Mass percent K2SO4 = 94.83%
Therefore, the mass percent of K2SO4 in the sample is approximately 94.83%.