Chem 105 Exam 1
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Chem 105 Exam 1
First exm of the session
All pure substances are either _______ or _______?
elements or compounds
An element is a pure substance composed of one _______?
Atoms of the same element are chemically __________?
A compound is a pure substance composed of __________ atom?
more than one type
Give an example of a element that exists in monatomic form?
Give an example for an element that exists in diatomic form?
Oxygen or Nitrogen
0) is an example of what?
The element that is found predominately is the earth's crust is?
In the atmosphere of the earth, what element is most abundant?
The breaking apart of water molecules to produce oxygen and hydrogen is the process called?
The reaction of oxygen molecules with hydrogen molecules to form water molecules is called?
What is accuracy?
denotes how close a measurement is to the actual value
What is precision?
denotes how close a set of values are to each other
What are the four rules for significant figures?
1- All non-zero digits are significant
2- Zeroes between non-zero numbers are significant
3- Zeros at the beginning of a number are never significant (place holders)
4- Zeros at the right end of the decimal are significnt
Memorize the metric system prefixes
Giga - G - 10
Mega - M - 10
Kilo - k - 10
Deci - d - 10
Centi - c - 10
Milli - m -10
Micro - μ
Nano - n - 10
Pico - p - 10
Femto - f - 10
What was J.J Thompson's contribution to science?
Measured the charge to mass ratio of the electron
What experiment did J.J Thompson work with?
What was Robert Millikan's contribution to science?
Measured the charge of the electron using the oil-drop experiment
What were Rutherford's three conclusions?
1- most of the atom is empty space
2- most of the mass is found in the nuclei
3- most of the positive charge is found in the nuclei
Metallic elements tend to ______ electrons, while non-metallic elements tend to ________ electrons
What does thyroxine do in the system?
Contains iodine, which is used to synthesize thyroxine in the thyroid. If Iodine is not found in the body it can cause thyroid malfunction
Alkanes can be determined using what formula?
Isotopes have the same number of _________ and different number of ___________ in their nuclei
Know the different stages of fuel additives.
1- Tetra-ethyl-lead (now outlawed)
2- aromatic hydrocarbons (benzene, napthalene, PDCB); found out to be carcinogenic
3- MTBE- gone by the mid 90's because it ended up in reservoirs