1 / 10

Today you need you packet ( Nuts and Bolts activity) and a calculator. Warmup

Today you need you packet ( Nuts and Bolts activity) and a calculator. Warmup. Atom A has 37 protons and a mass of 70 amu . Atom B has 33 protons and a mass of 66 amu . Atom C has 33 protons and a mass of 70 amu . Are these atoms all of the same element? Explain.

agrata
Download Presentation

Today you need you packet ( Nuts and Bolts activity) and a calculator. Warmup

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Today you need you packet (Nuts and Bolts activity) and a calculator. Warmup Atom A has 37 protons and a mass of 70 amu. Atom B has 33 protons and a mass of 66 amu. Atom C has 33 protons and a mass of 70 amu. • Are these atoms all of the same element? Explain. 2. Calculate the number of neutrons in each atom

  2. Nutz and Bolts (on board)

  3. Lab help stuff Actual SISS iron 21.05% sawdust 3.70% Values (write these down) sand: 56.76% salt: 18.49%

  4. The mass of an SISS sample is 4.56 grams. The mass of sand in this sample is measured to be 1.23 g, sawdust 1.30 g , and iron 0.92 g. • Calculate the mass percent of the sand, sawdust, and iron filings. Report answers to the hundredths place. b. What must be the mass percent of salt? Consider the accuracy of your answer (think in terms of the lab, not just in terms of math). c. The actual mass percent of salt is 18.49%. What is your % error? d. A larger 130.0 g SISS sample is obtained. i. What should be the percent composition of sand? ii. What is the mass of sand in this 130.0 gram sample?

  5. The mass of an SISS sample is 4.56 grams. The mass of sand in this sample is measured to be 1.23 g, sawdust 1.30 g , and iron 0.92 g. • Calculate the mass percent of the sand, sawdust, and iron filings. Report answers to the hundredths place. % composition = mass of substance x 100 mass of mixture 1.30 g x 100 = 4.56 g 0.92 g x 100 = 4.56 g 1.23 g x 100 = 4.56 g 20.18 % iron 26.97% sand 28.51 % sawdust

  6. % sand + % sawdust + % iron + % salt = 100% 75.66% + % salt = 100% % salt = 24.34 % b. What must be the mass percent of salt? Consider the accuracy of your answer (think in terms of the lab, not just in terms of math). c. The actual mass percent of salt is 18.49%. What is your % error? % error = |actual value – experimental value| x 100 actual value 1.23 g + 1.30 g + 0.92 g + x grams salt =4.56 grams x = 1.11 g salt (then calculate mass percent) % error = |18.49 – 24.34| x 100 18.49 31.64% error

  7. d. A larger 130.0 g SISS sample is obtained. i. What should be the percent composition of sand? ii. What is the mass of sand in this 130.0 gram sample? 26.97 % !!!!!!!! The mass of the sand will be different. But the ratio of each of the 4 substances SHOULD BE consistent throughout the sample % composition = mass of substancex 100 mass of mixture 26.97 = x ( 100 ) 130.0g x = 35.06 g sand

  8. Lab Followup Questions If I stamp a lab handout, do not lose it or you will not receive credit for the prelaboratory. Feel free to have me read any answers during class to make sure you’re on the right track. Answer questions on another sheet of paper and then write your final answer on the lab handout if you are concerned with being messy. Please do not attach additional sheets of paper though. Show your work on the calculations. If I can’t understand your work, I will give you a zero. I also had a busy schedule in high school. I also stayed up very late some nights because I procrastinated. These, to me, are not legitimate excuses for late or poor work or for copying.

  9. Lab Followup Questions I must be able to compare the answers of individuals from one group and NOTICE that the ideas and work came from different brains. I KNOW that there will be lots of similarities but do not plagiarize. It is not very easy to trick me into thinking that you know what you’re talking about when you really have no idea. I’ll know; please don’t waste my time, and yours, by being long-winded and not having a point. Use professional, scientific language. Avoid writing how you speak and making jokes in lab reports. Avoid the words “it” and “thing.” There are many nouns, tell me which one. “I wasn’t sure how to use the filter-thingy on the dirt, so, like, it kind of jacked up our stuff. LOL!”

  10. Lab Followup Questions - Error Analysis No experiment is error-free. This year, we are practicing how to identify the sources of error and analyze their impact on data. This will help you in life!!!! Your explanation must align to the results. For example, if your mass percent of sand is 40.96% and the actual value is 26.97%, saying that you spilled some sand or MUST HAVE spilled some sand wouldn’t explain your data. If a question says explain…then EXPLAIN…3 sentences maybe? Why did we use 2, not 1 SISS sample? “To get better data.” Ummm how about you elaborate, and maybe cite some differences between your first and second trial? As you finish your experiment, jot down errors that you could have possibly made during the lab yesterday, and TODAY. Scribble ideas on your lab handout near the procedure or data table, if necessary.

More Related