CEM 141 Chapter 1-Question with Correct Answers/ Verified
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Course
Cem 141
Institution
Cem 141
Matter -️️- Made up of atoms
Atoms -️️- Smallest distinguishable part of an element.
We use models (mental and physical) -️️to represent many chemical entities
We use different models -️️for different purposes
Theories (such as atomic theory) -️️change over time according to...
CEM 141 Chapter 1-Question with Correct Answers/ Verified
Matter - ✔️✔️- Made up of atoms
Atoms - ✔️✔️- Smallest distinguishable part of an element.
We use models (mental and physical) - ✔️✔️to represent many chemical entities
We use different models - ✔️✔️for different purposes
Theories (such as atomic theory) - ✔️✔️change over time according to the evidence available.
All atoms and molecules attract each other - ✔️✔️because of the attractive electrical forces
between them
Attractions - ✔️✔️lower the potential energy of the system
Repulsions - ✔️✔️tend to raise the potential energy
Stable systems form - ✔️✔️where the attractive forces and the repulsive forces are equal
The temperature of a phase change depends on - ✔️✔️the strength of the intermolecular forces
Discovery of the electron - ✔️✔️JJ Thomson
Cathode ray tube - ✔️✔️glass tube consisting of two electrodes under very low pressure, when
high voltage is applied, cathode emits particles that move toward anode
The type of the metal that the cathode was made of - ✔️✔️didn't affect the behavior of the ray
Observations from Thompson's Experiment - ✔️✔️- "Particles" emerged from one disc (the
cathode) and moved to other (the anode)
, - These particles could be deflected by electrical fields in a direction that would indicate they were
negatively charged
* (The particles could be deflected by magnetic fields)
* The particles carried the electrical charge - that is if the ray was bent, for example by a magnetic
field, the charge went with it
- The metal that the cathode was made of did not affect the behavior of the ray - so whatever the
composition of the ray - it appeared to be independent of the element that it came from.
What do scientists do? - ✔️✔️1. ask questions
2. design experiments
3. gather and analyze data and evidence (record their results and think about them)
4.make claims based on data and evidence that answer the question
5. develop models, explanations, and theories about how and why the universe behaves as it does
scientific questions - ✔️✔️questions that can be answered by doing experiments, making
observations, taking measurements. Experiments must be replicable.
What do you need if you're going to make a claim? - ✔️✔️evidence
A scientific model - ✔️✔️Can be a drawing or a graph or a diagram or an equation. We use models
to help us make sense by predicting what will happen and explaining how something happens.
constructing a scientific explanation - ✔️✔️Claim
Evidence
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