click below
click below
Normal Size Small Size show me how
SHAPES AND MOLE5
Question | Answer |
---|---|
STRAND OF DNA HELD TO OTHER BY | HYDROGEN BONDS. |
THE BASE ADENINE LINKED TO THYMINE IN OTHER STRAND | BY 2 HYDROGEN BONDS |
CYTOSINE AND GUANINE HELD | BY 3 HYDRO BONDS. |
PHYSICAL PROPERTIES: DEPEND ON | FORCES E.G. MELTING A SOLID |
A SOLID CONSIST OF A | REGULAR ARRANGEMENT OF PARTICLE WHICH VIBRATE ABOUT A FIXED POINT AND CANNOT MOVE. |
WHEN N SOLID HEATED VIBRATION | INCREASED TEMPERATURE RISES, WHEN MELTING TEMPERATURE REACHED THE STRUCTURE OF SOLID BREAKS. |
AS HEATING CONTINUOUS MORE SOLID MELTS | TEMP STAYS SAME UNTIL SOLID HAS MELTED. |
WHEN MOLTEN THE PARTICLE | FREE TO MOVE AROUND. |
IF FORCES BETWEEN PARTICLES ARE STRONG | MUCH ENERGY IS REQUIRED TO BREAK DOWN THE STRUCTURE OF THE SOLID =HIGH MELTING POINT. |
BOILING A LIQUID IN LIQUID THE PARTICLES ION ATOMS MOLECULES | ARE CLOSE TOGETHER BUT POSITIONS ARE RANDOM AND THEY TUMBLE OVER EACH OTHER. PARTICLE MOVE AT DOFF SPEEDS AND COLLIDE. |
WHEN LIQUID IS HEATED | THE PARTICLE GAIN KINETIC ENERGY AND SPEED INCREASES. SOME PARTICLES MOVE FAST T ESCAPE AS GAS –(EVAPORATION). |
WHEN BOILING TEMP REACHED SOME PARTICLE | ESCAPE FROM MIDDLE OF LIQUID ,BUBBLES OF GAS PRODUCES AND LIQUID BOILS. IF THE FORCES BETWEEN THE PARTICLES STRONG MUCH ENERGY NEED TO SEPARATE = HIGH BOILING TEMPERATURE. |
WHAT IS EVAPORATION OF A PARTICLE | WHEN THE PARTICLES MOVE SO FAST THEY ESCAPEA AS GAS. |
AN ELECTRIC CURRENT IS | FLOW OF CHARGE (ELECTRONS ION). |
NAME THE TYPES OF SOLID STRUCTURE (6) | IONIC, GIANT ATOMIC, METALLIC ,HYDROGEN BONDED MOLECULAR ,POLYMERIC, SIMPLE MOLECULAR. |
HOW ARE ION ARRANGED | IONIC HAS REGULAR ARRANGEMENT – LATTICE |
MELTING DEPENDS ON | STRENGTH OF ION ION FORCES , IONS WITH 2+ 2- HAVE STRONG FORCES. |
IONS WITH AS SMALL RADIUS | STRONGER FORCES OF ATTRACTING THAN LARGE. |
THE MELTING TEMP DEPENDS ON | LATTICE STRUCTURE LATTICE WITH A ION RATIO 2:1 MELT AT A LOWER TEMPERATURE THAN EXPECTED. |
WHY DON’T IONIC SOLID CONDUCT | ION ARE FIXED IN LATTICE CANNOT MOVE. BUT WHEN MOLTEN /DISSOLVED CAN MOVE AROUND. (CONDUCT BY MOVEMENT OF CHARGE IONS), METALS ON MOVEMENT OF ELECTRONS). |
MG2+ HAS A SMALLER RADIUS THAN CA2= SO | STRONGER FORCE OF ATTRACTION. |
GIANT ATOMIC SUBSTANCES /NETWORK COVALENT ARE LINKED | BY COVALENT BONDS. CARBON HAS 2 MAIN FORMS- IN DIAMOND EACH CARBON ATOM HAS 4 SIGMA BONDS TO 4 OTHER CARBON IN A GIANT TETRAHEDRAL ARRANGEMENT – 109.5, |
DIAMOND HAS HIGH MELTING PINT BECAUSE | EACH CARBON BONDED TO 4 OTHERS(COVALENTLY). |
GRAPHITE ARRANGEMENT | EACH CARBON ATOM BONDED BY 3 OTHER BY SIGMA BONDS FORMING INTERLOCKING HEXONAL RINGS. |
THE 4TH ELECTRON IN GARPHITE ... IS IN THE P ORBITAL WHICH FORMS | A DELOCALISED CLOUD ABOVE AND BELOW THE RINGS. |
WHY DOES GARPHITE SLIDE | THE PLANAR RINGS ARE WEAKLY BONDED BY LONDON FORCES SO CAN SLIDE OVER EASILY.(THIS IS WHY PENCIL LEAVES A MARK). |
THE DELOCALISE ELECTRONS ALLOW GRAPHITE | IT TO CONDUCT ELECTRICITY. |
C60 – DISCOVERED | BY FIRING A LASER AT A DISC OF CARBON AND CONDENSING THE VAPOUR FORMED CONSIST OF 20 INTERLOCKING HEXAGONS AND 12 PENTAGON EACH CARBON HAS 3 SIGMA BONDS AND THE 4TH ELECTRON IS DELOCALISED. |