chapters 1&2 Flashcards
1 PETAbyte
10^15
1 TERAbyte
10^12
1 GIGAbyte
10^6
1 MEGAbyte
10^3
1 KILObyte
10^3
1 DECImeter
10^-1
1 CENTImeter
10^-2
1 MILLImeter
10^-3
1 MICROmeter
10^-6
1 NANOmeter
10^-9
1 PICOmeter
10^-12
1 FEMTOmeter
10^-15
What to do when uncertain of measurements?
Uncertainty of measurement creates uncertainty in time!
Significant figures in 4 easy steps:
- All nonzero digits and trapped zeroes are significant!
- Zeros that start a number are not significant!
- Zeros that end a number without a decimal are not significant!
- A nonsignificant zero can be made significant with a bar over it!
Adding and subtracting significant figures:
The answers last digit will be in the same place as the last digit of the least certain measure (least accurate)!
Multiplying and dividing significant figures:
The number of significant figures in the answer will equal the lowest number of significant figures in any factor! (The one that has the least amount of numbers!)
Volume:
1L = 1000mL = 1000cm^3
Robert Boyle:
All matter is made up of either elements or compounds!
Element:
Any substance that cannot be broken into simpler components by chemical means!
Compound:
Any substance that can be broken into simpler components by chemical means!
John Dalton:
- All matter is made up of atoms (elements are composed of atoms!)
2.compounds are composed of atoms of more than one element! - A chemical reaction involves the rearrangement of atoms!
4.All atoms of a given element are identical! - Atoms are indestructible!
JJ Thomson:
Subatomic particle (smaller than atom!)
Electrons: negatively charged subatomic particles
“Plum-pudding” model of the atom:
* 1. No positively charged particles!*
* 2. Electrons are the only particles= only mass!*
3. Atoms are mostly empty spaced (can’t have negative charges close to each other)!
1 and 2 are incorrect!
Ernest Rutherford:
Protons:positively charged subatomic particles!
Rutherford’s atomic model:
1. Atoms contain a small, dense positively charged center called the nucleus!
2. The nucleus has almost the entire mass of the atom!
* 3. Electrons are dispersed in the empty space of the atom! *
3 is incorrect!
James Chadwick:
Neutrons: neutral subatomic particles
Atomic number:
(z) The number of protons in an atom of an element
(It is found on the top of an element on the periodic table!)
Elements:
Elements are electrically neutral!
The same element can have different number of neutrons!
Elements with similar chemical and physical properties are placed in the column “group!”
To facilitate this arrangement, elements are also placed in rows, “period!”
Isotopes:
Atoms with the same number of protons, and electrons with different number of neutrons!
Mass number (A):
Number of protons + the number of neutrons!
Atomic mass unit (amu or u):
One twelfth the mass of carbon - 12 atom, equal to 1.66 X 10^-24
Dimitri Mendeleev:
Arranged elements by atomic mass!
The periodic law:
When the elements are arranged in increasing mass order, certain properties repeat periodically!