CEM 141 Chapter 1 Learning Objectives with Questions and correct answers
5 views 0 purchase
Course
CEM 141
Institution
CEM 141
Identify and explain the similarities and differences between atoms, molecules, elements, and
compounds - Atoms: the smallest unit of ordinary matter that forms a chemical element
Molecules: electrically neutral group of two or more atoms held together by chemical bonds.
Elements: consists only ...
CEM 141 Chapter 1 Learning Objectives with Questions and correct answers Identify and explain the similarities and differences between atoms, molecules, elements, and compounds - ✔✔Atoms: the smallest unit of ordinary matter that forms a chemical element Molecules: electrically neu tral group of two or more atoms held together by chemical bonds. Elements: consists only of the same atoms, with the same number of protons Compounds: a chemical substance composed of atoms from 2+ elements held together by chemical bonds Make an argument (claim, evidence, reasoning) for the existence of atoms - ✔✔Claim: atoms are the smallest unit of matter that forms an element and make up everything in the world Evidence: an example is water, which is a liquid we drink and makes up more than half our body. Reasoning: water is made up of hydrogen and oxygen atoms, we know this because they can be boiled and evaporate into the air and can be separated/added to each other. Make an argument(claim, evidence, reasoning) for the existence of electrons - ✔✔Claim : electrons are subatomic particles within an atom which hold a negative charge Evidence: JJ Thompson used a cathode ray tube to prove the existence of electrons. This CRT was connected to metal discs coated with a chemical that responds to electric and ha s wires embedded inside. Reasoning: with his CRT, he found that the rays were negatively charged, emerged from one end and moved to the other, can be deflected by magnetic fields, carried an electric charged which bent the rays present in the CRT, and foun d the metal did not affect the ray behavior. He concluded the charge must come from inside the atoms with this data and developed the plum pudding model with it. Make an argument(claim, evidence, reasoning) for the existence of the existence of a small, massive, and positively charged nucleus - ✔✔Claim: a nucleus is a subatomic particle inside an atom. Evidence: Rutherfords experiment using helium atoms which he projected onto a gold foil. Reasoning: most of the particles(He atoms) went straight through th e foil. However, some atoms were deflected off the foil and an even smaller amount bounced right back to where they were initially projected from. This is because of the bigger nuclei inside gold atoms which the He at times would come into contact with, ca using them to deflect. The nucleus must exist or else the He atoms would not have been deflected, and all of them would have gone straight through. (nucleus positive because electrons of He repel it, it is small because MOST went through) How does a scientific theory differ from everyday use of the term "theory" - ✔✔In everyday use, the word "theory" often means an untested hunch, or a guess without supporting evidence. But for scientists, a theory has nearly the opposite meaning. ... A the ory not only explains known facts; it also allows scientists to make predictions of what they should observe if a theory is true.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller MikeHarris. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.99. You're not tied to anything after your purchase.
