chemistry unit two

alpha rays

nuclei (He+2) bend toward the negative plate because they have a positive charge.

the most common isotope of carbon

mass 12

atomic # 6

carbon 12

what are the five ways in which a nuclear reaction differs from a chemical reaction?

-nuclear reactions involve nuclei not molecules

-the rate of a nuclear reaction is not affected by change in temp, pressure or catalyst

-nuclear reactions of an atom are the same weather it is in a chemical compound or elemental form.

-different isotopes of an element have essentially the same behavior in chemical reactions but often different behaviors in nuclear reactions

Beta rays

electrons(e-) bend toward the positive plate because they have a negative charge.

gamma rays

photons(y) that do not bend toward either plate because they have no charge.

how can a nucleus emit an electron during beta decay when there are no electrons present in the nucleus to begin with?

during beta decay a weak nuclear force causes a neutron to transform into a proton and in the process emits an electron

what is the difference between an alpha particle and a helium atom?

An alpha particle is the positively charged nucleus of a helium atom, lacking electrons, while a helium atom is electrically neutral with two orbiting electrons.

alpha particle

beta particle

alpha emission equation for uranium-238

beta emission equation for iodine-131

positron emission for potassium-40

electron capture

delta g determines

if the reaction is spontaneous

what indicates a spontaneous reaction

ΔG < 0

percent yield

a substance that is oxidized causes

reduction

a substance that gives up an electron is

a reducing agent

a substance that is reduced is

oxidizing agent

delta g =

delta H - T delta S or G products - G reactants

if bonds broken is greater than bonds formed then energy in - energy out =

+ delta H endothermic, heat absorbed, unfavorable

delta H =

bonds broken - bonds formed

energy in - energy out

if bonds broken is less than bonds formed than energy in - energy out =

- delta H, exothermic, releases heat, favorable

delta S =

entropy of products (SP)-entropy of reactants (SR)

delta H

change in heat (enthalpy)

delta S

change in disorder (entropy)

entropy of products greater than entropy of reactants, than

delta S is favorable

entropy of products is less than entropy of reactants, than

delta S in unfavorable

Oil Rig

oxidation is gaining electrons

Reduction is gaining electrons

Avogadro's law

V1/n1=V2/n2

the volume of gas is directly proportional to its molar amount at a constant pressure and temperature

STP

=0c=273.15k and 1atm=760mmHg

standard molar volume

22.4 L/mol

r=

0.0821 L atm/mol K

always soluble

NH4+, Li+, Na+, K+, NO3-, ClO4-, CH3CO2-

usually soluble

Cl-, Br-, I-, SO42-

insoluble everything else

e.g. CaCO3