[writer.at.heart415]

Mass of sample: 86.42 g
Initial volume of water: 27.5 mL
Volume of water with sample: 39.3 mL

Part 1: Using the data above, calculate the density.

I did 86.42g / 27.5mL and got 3.14 g/mL. Where did I go wrong?

Part 2: The sample was determined to be zinc. Calculate the percentage error.

I did ((39.3 - 7.133) / 7.133) x 100 and got 44.9%. Again, where did I go wrong?

Part 3: What error is introduced if the volume of the sample is determined first and then weighed without drying? Would it increase or decrease the experimentally determined value of the property? Explain your reasoning.

I wrote that the water on the sample will interfere with the measurement by increasing it because the more volume there is higher a number so the overall answer will be higher. My teacher circled the word volume and asked why there's more volume...so what's wrong with that?

Part 4: The heat of fusion for zinc is 100.7 J/g. How much heat is required to melt this sample of zinc? Show you work below.

I did the equation q = m x heat of fusion, 4.18 x 100.7 = 421 J/g. Apparently 4.18 is not the mass...what is, then? How can I figure it out?

Part 5: The specific heat of zinc is .375 J/gxC. ow much heat is required to raise the temp of zinc from 350.0C to its melting point?

I did the equation q = m x C x deltaT, q = 4.18 x .385 x 70 and got the answer 112 J/g. Again, apparently the mass of zinc is not 4.18, so how can I figure out the mass?

[opti384]

part1: what is the volume of the sample?

part2: Hmm.. I don't get where this ((39.3 - 7.133) / 7.133) x 100 come from.

part3: Think this way. What will be the difference between a wet sample and a dry sample?

part4: Mass of sample: 86.42g.

part5: Mass of sample: 86.42g

[Borek]

Part 1: Using the data above, calculate the density.

Density of what?

Part 2: The sample was determined to be zinc. Calculate the percentage error.

Percentage error of what?

[Heli0x]

Perhaps you could try using Archemedes' principle, although I'm not certain if this works here. I did get an answer similiar to the litterature value of Zinc when I tried to calculate.



Where F equals mg (mass times standard gravity).

[JGK]

Mass of sample: 86.42 g
Initial volume of water: 27.5 mL
Volume of water with sample: 39.3 mL

Part 1: Using the data above, calculate the density.

I did 86.42g / 27.5mL and got 3.14 g/mL. Where did I go wrong? You have divided the mass of the sample by the volume of water - WRONG. You need to divide the mass of the sample by the volume occupied by that mass

Part 2: The sample was determined to be zinc. Calculate the percentage error.

I did ((39.3 - 7.133) / 7.133) x 100 and got 44.9%. Again, where did I go wrong?

God Knows, you need the answer from the first part than you need to calcylate that as percentage of 7.133 (which I assume is your book value of zinc density) and subtract 100

Part 3: What error is introduced if the volume of the sample is determined first and then weighed without drying? Would it increase or decrease the experimentally determined value of the property? Explain your reasoning.

I wrote that the water on the sample will interfere with the measurement by increasing it because the more volume there is higher a number so the overall answer will be higher. My teacher circled the word volume and asked why there's more volume...so what's wrong with that?
what do you measure by weighing?

Part 4: The heat of fusion for zinc is 100.7 J/g. How much heat is required to melt this sample of zinc? Show you work below.

I did the equation q = m x heat of fusion, 4.18 x 100.7 = 421 J/g. Apparently 4.18 is not the mass...what is, then? How can I figure it out?

Part 5: The specific heat of zinc is .375 J/gxC. ow much heat is required to raise the temp of zinc from 350.0C to its melting point?

I did the equation q = m x C x deltaT, q = 4.18 x .385 x 70 and got the answer 112 J/g. Again, apparently the mass of zinc is not 4.18, so how can I figure out the mass?

Help with parts 1 - 3 are in bold