I am not good with math problems. I need help with these two problems. I'm not sure what equations to use. please help.
A student heated a hydrated salt sample with an initial mass of 4.9702 g. After the first heating, the mass had decreased to 3.0662g.
1. if the sample was heated to constant weight after reheating, what is the minimum mass that the sample can have after the second weighing? Show how you determined your answer.
2. the student determined that the mass lost by the sample was 1.8053. What was the percent in the original hydrated sample. Show calculation setup.
thanking you in advance
The answer to A depends upon what kind of accuracy/precision you are looking for. I think 0.2 to 0.3 mg is pretty standard. So I would go with 3.0662 - 0.0002 = ? or on a bad day 3.0552-0.0003 = ? Frankly, that is in the neighborhood of 7% error and that isn't great but it's tough to do better than about 0.2 mg with a top line balance that weighs to 0.2 mg. I would be interested in knowing what your prof considers constant weight and he s/he determines it.
2. % H2O = (mass lost/mass sample)*100 = ?
I just looked at this old problem. 0.2 mg is 0.0002 g and that is closer to (0.0002/3.0662)*100 = not anywhere close to 7%. More like 0.007%.
Sure! I'd be happy to help you with these math problems. Let's break down each problem and figure out the equations and steps to solve them.
Problem 1:
To determine the minimum mass that the sample can have after the second weighing, we need to know the difference between the initial mass and the mass lost during the first heating. This will give us an idea of how much more mass the sample can potentially lose.
Step 1: Calculate the mass lost during the first heating.
Mass lost = Initial mass - Mass after first heating
Mass lost = 4.9702 g - 3.0662 g
Mass lost = 1.904 g
Step 2: Since the sample was heated to constant weight after reheating, it means that all water has been removed. So, the minimum mass that the sample can have after the second weighing is the mass of the anhydrous salt (without water) left in the sample.
Therefore, the minimum mass after the second weighing is:
Minimum mass = Mass after first heating - Mass lost
Minimum mass = 3.0662 g - 1.904 g
Minimum mass ≈ 1.1622 g
Therefore, the minimum mass that the sample can have after the second weighing is approximately 1.1622 grams.
Problem 2:
To determine the percent of the original hydrated sample lost during the first heating, we need to calculate the percent loss in mass relative to the original mass.
Step 1: Calculate the percent loss in mass.
Percent loss = (Mass lost / Initial mass) x 100
Given that the mass lost by the sample is 1.8053 g and the initial mass is 4.9702 g, we can substitute these values into the equation.
Percent loss = (1.8053 g / 4.9702 g) x 100
Percent loss ≈ 36.3 %
Therefore, the percent loss in the original hydrated sample during the first heating is approximately 36.3%.
I hope this helps! Let me know if you have any further questions.