chapter4-basic food chemistry Flashcards
What part does protons and neutrons are same as each other?
mass
how much weight is e-?
1836 e- =one proton
how e- prefer to move?
in pairs
how many elements naturally and scientists create?
90
27
what determine which element an atom is?
number of protons
who develop the periodic table?
Russian chemist- Dmitry Mendeleyev
what is AMU? what is one AMU?
atomic mass unit- mass of a proton or neutron
not all atoms of an element have the same number of neutrons. T/F
true
what are columns called?
groups 18
what are rows called?
periods 7
how does metal usually look like? except for?
solid in rtp.
Mercury-liquid in rtp.
what are metals good at?
conduct heat and electricity.
how does half of non metals look like?
gas in rtp. brittle易碎 when solid.
what does chemical formula represent?
one molecule or unit of a compound.
what is structural formula?
show the arrangement of the atoms in the molecule.
what is chemical bond?
force hold 2 atoms together
what are shells refers to?
energy level or their principle quantum number.
how is stable element likely to form chemical bond?
least likely
what is ionic bond?
e- are transfer from one atom to another, cause both atoms have a charge.
what is ionic bond result of?
attraction between a + and - charge. e.g. NaCl
what causes a crystalline?
the regular arrangement of atoms–the result of interaction between - and
+ ions.
what happen after Na ions push away Na and towards to Cl?
cause sodium and chlorine atoms form an alternating pattern or structure.
why ionic bonds tend to disslove in water?
one end of water molecule slightly +, the other side is slightly -
where is ionic bond form?
between metal and non metal.
what can KCl do?
no-salt seasonings调味品
what can CaCl do?
as drying agent
water molecule are formed by covalent bond or ionic bond?
covalent bond
who develop lewis structure?
Gilbert Newton Lewis- US chemist
how matter can be classification?
pure substance and mixtures
how pure substance can be classification?
compounds and elements
how compound can be classification?
organic and inorganic
how mixture can be classification?
homogeneous and heterogeneous
which 3 elements are important and good health in food science?
iron, calcium, zinc
what does most organic compounds have?
chains or rings of carbon.
hydrogen and oxygen
all source of energy in diet is organic/inorganic?
organic
Is milk a mixture or compound?
mixture
what is solution?
homogeneous mixture of one material dissolved in another.
how can substances in heterogeneous mixtures be separated?
mechanical means
what does solid have?
definite shape and volume
is phase change reversible?
yes.
what is the difference between fluid and non-newtonian fluids?
fluids: liquid and gas
non-newtonian fluids:liquid and solid. –>面粉团 玉米糊 比较难移动
what is chemical change example?
browning when toasted bread.
mix water and baking powder.
fermenting grape.
release gas, odor, color and flavor change.
what is a reversible chemical change?
the way your body use food
