A 25.0 mL aliquot of a well-shaken and filtered sample of river is pipetted into an evaporating dish. The sample was heated to dryness. Assume the density of the river water was 1.01g/mL. The following data were collected for Trial 1. Complete the data. Record values with the correct number of significant figures.
1. Mass of evaporating dish (g): 26.217
2. Mass of water sample plus evaporating dish (g): 51.467
3. Mass of water sample (g): 25.25g (THIS WAS WHAT I CALCULATED- IS IT RIGHT?)
4. Mass of dried sample plus evaporating dish (g): 35.291
5. Mass of dissolved solids in 25-mL aliquot of filtered sample (g): HOW DO I FIND THIS?
6. Mass of dissolved solids per total mass of sample (g solids/ g sample) show calculation..HOW DO I FIND THIS?
7. Total solids (g solids/ g sample, ppt). HOW DO I FIND THIS?
PLEASE HELP ME FIGURE THIS OUT? I DON'T UNDERSTAND.
thank you!
part 3 is right.
part 5 is 4-1
part 6 is 5-3
I don't understand the question for 7. g solids/g sample is the same as part 6.
question 5.6 and 7
No problem, I'm here to help! Let's go through the questions step by step:
1. Mass of evaporating dish (g): 26.217
2. Mass of water sample plus evaporating dish (g): 51.467
3. Mass of water sample (g): To find the mass of the water sample, subtract the mass of the evaporating dish (26.217g) from the mass of the water sample plus evaporating dish (51.467g):
Mass of water sample = Mass of water sample plus evaporating dish - Mass of evaporating dish
= 51.467g - 26.217g
= 25.25g
So, your calculation is correct. The mass of the water sample is 25.25g.
4. Mass of dried sample plus evaporating dish (g): This value is already given as 35.291g.
5. Mass of dissolved solids in 25-mL aliquot of filtered sample (g): To find the mass of dissolved solids, subtract the mass of the dried sample plus evaporating dish (35.291g) from the mass of the water sample plus evaporating dish (51.467g):
Mass of dissolved solids = Mass of water sample plus evaporating dish - Mass of dried sample plus evaporating dish
= 51.467g - 35.291g
= 16.176g
So, the mass of dissolved solids in the 25 mL aliquot is 16.176g.
6. Mass of dissolved solids per total mass of sample (g solids/g sample): To find this, divide the mass of dissolved solids (16.176g) by the mass of the water sample (25.25g):
Mass of dissolved solids per total mass of sample = Mass of dissolved solids / Mass of water sample
= 16.176g / 25.25g
= 0.640g/g
So, the mass of dissolved solids per total mass of the sample is 0.640g/g.
7. Total solids (g solids / g sample, ppt): This value represents the concentration of solids in parts per thousand (ppt). To find this, multiply the mass of dissolved solids per total mass of sample (0.640g/g) by 1000:
Total solids = Mass of dissolved solids per total mass of sample * 1000
= 0.640g/g * 1000
= 640 ppt
So, the total solids concentration is 640 ppt.
To find the mass of dissolved solids in the 25-mL aliquot of filtered sample, you need to subtract the mass of the dried sample plus evaporating dish (35.291 g) from the mass of the water sample plus evaporating dish (51.467 g).
Mass of dissolved solids in the 25-mL aliquot of filtered sample = mass of water sample plus evaporating dish - mass of dried sample plus evaporating dish
= 51.467 g - 35.291 g
= 16.176 g
So, the mass of dissolved solids in the 25-mL aliquot of filtered sample is 16.176 g.
To find the mass of dissolved solids per total mass of the sample (g solids/g sample), you divide the mass of dissolved solids by the mass of the water sample.
Mass of dissolved solids per total mass of the sample (g solids/g sample) = mass of dissolved solids / mass of water sample
= 16.176 g / 25.25 g
≈ 0.64 g/g
So, the mass of dissolved solids per total mass of the sample is approximately 0.64 g/g.
To find the total solids in g solids/g sample (ppt), you multiply the mass of dissolved solids per total mass of the sample by the density of the river water.
Total solids (g solids/g sample, ppt) = mass of dissolved solids per total mass of the sample * density of the river water
= 0.64 g/g * 1.01 g/mL
≈ 0.65 g/g
So, the total solids in g solids/g sample (ppt) is approximately 0.65 g/g.