Demonstrate understanding of thermochemical principles and the properties of particles and substances
Lewis structures also known as Lewis diagrams are diagrams that show the bonding between atoms of a molecule and lone pairs or non bonding electrons. Using these structures it is possible to predict the shapes of covalent molecules.
Working out Lewis structures involves the use of an arcane set of rules the only justification for which is that they appear in chemistry text books and examinations.
There is an app for this. Learn how to construct the diagrams but use the app to check answers. It works by plugging the formula. You don”t need to use subscripts.
sulphuric acid H2SO4
You can also type in the name methane.
State Highway 48, the Bruce road.
The Bruce Road was built 10,500 years after the rim of the ancient Iwikau volcano collapsed and large dry avalanches flowed into the valleys below. The original steep sided edifice became unstable as supporting glaciers receded. Avalanche material crashed through the valley containing the Chateau Tongariro and Whakapapa ski fields.
These avalanche deposits are collectively known as the Murimotu formation.
The present summit .
Tahurangi (Tg; 297m) is in the foreground. Left in the distance is Paretaitonga (Pt; 2751m) formed 18 to 12000 years ago.
Across the Crater Lake lies Cathedral rocks (Cr; 2663m), Te HeuHeu (TH; 2732m) and Tukino (Tk; 2720m) the result of cone building eruptions between about 15,000 and 12,000 years ago.
Pyramid Peak (Py; 2645 m) is part of a small cone that partly surrounds an active vent beneath the lake. It probably started erupting tephra and thin lava flows about 2,500 years ago. The picture isn’t mine, I’ll get up there soon probably after my 70th birthday!
The Iwikau Cone.
A residual scar from the catastrophic rim collapse can be seen between Te Heuheu (TH; 2372m) and Paretetaitonga ( Pt; 2751m) peaks on the north-west of Ruapehu.
Volcanic activity began after this large scale detachment. The event was probably triggered by earquakes undetected by yet to be invented seismic sensors. The Chateau itself had a lucky escape because it han’t been built yet. Successive eruptions of lava flows and pyroclastics within the collapse scar gradually built Iwikau, a new Iwikau cone.
Lava and pyroclastic deposits from the Iwikau cone are superimposed on Murimotu deposits in the whakapapa skifield area.
A rapid, bumpy descent from the Iwikau Cone.
The downward momentum of the detached volcanic material decreased as it hit the flat ring plane. It slithered to a halt, crumpling slightly as it dotted the landscape with characteristic mound shapes. The mounds consist mainly of andesitic-dacitic volcanic debris.
Lava and pyroclastic deposits cover the Murimotu formation in the whakapapa skifield area.
Distinctive layers preserved during descent.
Course layer structures are visible. This is typical of dry avalanche deposits and probably indicates that large chunks of the mountain made a rather fast but traumatic descent onto the ring plain.
The andesite/dacite blocks in view are the same age and have similar chemical composition to material found near the summit at the inferred original site.
Damaged in transit
Complete chunks of the original mountain crashed and bounced down steep terrain before sliding to a halt beneath the Chateau. large rocks surrounded by fine grained volcanic bubble wrap were cracked and broken like delicate packages roughly handled in transit .
On the right a large block has cleanly snapped in three during its violent descent.
Part 1- tiny particles.
Food colouring spreads out when it is dropped in water.
Rotorua can smell a bit when gasses seep into the air from deep underground.
You know very quickly when someone has used Lynx in the classroom.
How can matter spread out so easily. It must be made of lots of tiny bits that can move about.
The first part of the theory is that all matter, everything that takes up space, consists of very tiny particles.
Solids liquids and gasses, the three main types of matter.
The concrete around the pool is definitely a solid.
The water in the pool is a liquid. The pool is dirty and there are also bits of solid present.
…….. but where is the gas in the picture?
Solids like concrete have a fixed shape.
Liquids can be poured and take the shape of their container. They can’t be compressed.
Gasses expand to fill up the space that contains them. They can also be compressed into a smaller space like air pumped into a football.
Part 2 – spacing and movement.
According to our theory everything consists of small particles.
How close to each other do particles approach?
How fast are they moving and do they collide?
How does our theory explain the behaviour of solids liquids and gasses?
Particles are close together in fixed positions.
Particles can move slightly by vibrating.
Particles are close together but they are free to move around each other and change their position.
The particles are much more widely spaced in a gas. They can move around freely in the container bouncing of walls and each other.
Solids liquids and gasses.
When you heat a solid to a high enough temperature it melts and becomes liquid.
When you heat a liquid to a high enough temperature it boils and becomes a gas.
Part 3 – solids can become liquids and liquids can become gasses or the other way around.
The third part of the theory. When a substance is heated the particles pick up extra energy. The particles vibrate or move faster.
- As the particles in the solid vibrate faster they eventually start to break away from each other and move freely.The solid becomes liquid.
- As the particles in the liquid warm up they move past each with increasing speed. Eventually at the boiling point they have enough heat energy and are moving fast enough to break free completely and become a gas.
- Melting, when a solid becomes liquid on heating.
- Freezing, when a liquid becomes solid on cooling.
- Boiling, when a liquid becomes a gas at its boiling point.
- Condensing, when a gas becomes a liquid