Chemistry Exam 1-General Knowledge

hypothesis

a tenative explanation of a set of observations

Law

concise verbal/mathematical statement of a relationship between phenomena that is universally consistent under the same conditions.

Nanometer

10^-9

Picometer

10^-12

Converting Celsius to Fahrenheit

?F=9F/5C(C)+32F

Converting Fahrenheit to Celsius

?C=(F-32F)x5C/9F

Converting Celsius to Kelivn

?K=(C+273.15)x1K/1C

Adding or Subtracting scientific notation

• same exponent? add numbers together

• different exponent? move decimal on ONE scientific notation until exponents match. (4.31×10^4)+(3.9×10³)—> (4.31×10^4)+(0.39×10³)=4.70×10^4

Multiplying or dividing scientific notation

• multiplying=multiply the numbers together, ADD exponents

• dividing=divide the numbers, SUBTRACT exponents

Mixture

combination of 2 or more things, they retain their identities (i.e cement, air, drinks)

mixtures are either homo- or hetero-geneous (homo=same. sugar dissolves in coffee) (hetero=different. gravel and sand)

Substance

a form of matter that has a definite composition and distinct properties (water, ammonia, sugar, gold)

Compound

a substance composed of atoms of 2 or more elements chemically united (can only be separated by chemical means

Extensive property

depends on how much matter is being considered

Intensive property

does not depend on how much matter is being considered

Proton

1/1p

Neutron

1/0n

Electron

0/-1e

Alpha particle

4/2a

Beta particle

0/-1b

Positron

0/+1 b

True/False: an alpha particle is the same as a Helium nucleus

True

True/False: beta particles (0/-1b) is the same as an electron (0/-1e)

True

2 rules for balancing nuclear equations

1. total number of protons + neutrons in the products AND the reactants must be the same (conservation of mass #) (top number A)

2. The total atomic number (bottom number, Z) must be the same on both sides