Alkanols vs Alkanals

Question: Differentiate between alkanols and alkanals.

Answer: Alkanols and alkanals are both organic (carbon containing) compounds but they have different functional groups.
Alkanols contain the OH (hydroxyl) functional group.
Alkanals contain the C=O (carbonyl) functional group on a terminal (end) carbon atom of the carbon chain.
Because they have different functional groups they undergo different chemical reactions and will have different physical properties.
The physical and chemical properties of alkanols, for example, can be found at AUS-e-TUTE's page on Properties of Alkanols.

Tonight's the Night

On Friday 21 August 2015 Mt. Stromlo Observatory will be leading Australia in attempting to break two Guinness World Records - Most People Stargazing at a Single Site (Canberra) and Most People Stargazing Across Multiple Sites in a Country (Australia).
Go to http://www.anu.edu.au/events/mt-stromlo-observatory-world-record-night for more information.

Not in Canberra?
No problems.
There are more than 40 sites registered to take part in the attempt to break the World Record for Most People Stargazing Across Multiple Sites in a Country.
Go to http://rsaa.anu.edu.au/world-record-stargazing to learn more.

Haven't got a telescope? Bring binoculars along instead (they will still count for stargazing!).

UPDATE 23/8/2015
1,869 people braved the cold weather in Canberra to set a new Stargazing record surpassing the previous record of 649 by more than 1,000 people!

A second world record was being attempted for the most people stargazing at multiple sites around Australia, and while estimates of around 10,000 people have been suggested which would beat the previous record of 3,007, we are still waiting for exact numbers and confirmation.

Chemical Equilibrium

To understand chemical equilibrium you need to realise that

1. chemical reactions that are in equilibrium DO NOT go to completion. 
2. "reactants" and "products" are all present at equilibrium
3. the "things" that are in equilibrium are the "reactants" and "products" whose concentrations can be changed (that is, substances that exist in solution).
4. equilibrium is the state in which the rate of the forward reaction (reactants → products) is the same as the reverse reaction (products → reactants

Knowing this, we can then write:

• a mass-action expression (http://www.ausetute.com.au/massaction.html)

And then

• the equilibrium law expression (http://www.ausetute.com.au/equilibriumlaw.html)

Which at equilibrium, results in an expression for the

• equilibrium constant (http://www.ausetute.com.au/equicons.html)

Which can be used to:

• calculate concentration (http://www.ausetute.com.au/ricetable.html)
• determine the extent of a reaction (http://www.ausetute.com.au/kextent.html)
• determine the equilibrium constant for the reverse reaction (http://www.ausetute.com.au/kreverse.html)
• determine whether a chemical reaction is exothermic or endothermic (http://www.ausetute.com.au/ktemperature.html)

HCl as a Primary Standard?

Question: Why is HCl not suitable as a primary standard?
Answer:  There are three main reasons why HCl is not suitable as a primary standard:

• HCl is not a solid at room temperature and pressure. 
• HCl cannot be obtained at a very high purity.
• HCl does not have a high molecular mass.

You can find out more about what makes, and does not make, a primary standard at:
http://www.ausetute.com.au/titrstand.html

Which Element has the Smallest Atomic Radius?

Question: Write the symbol for the element which has the smallest atomic radius Na, Si, Mg, P.

Answer: In general, atomic radius decreases going across a period of the Periodic Table.
Sodium (Na), magnesium (Mg), silicon (Si) and phosphorus (P) all belong to the third period.
In order of increasing atomic number they are: Na (Z=11), Mg (Z=12), Si (Z=14), P(Z=15)
Therefore, in order of decreasing atomic radius they are: Na > Mg > Si > P
So, phosphorus, symbol P, has the smallest atomic radius.

Read more about trends in atomic radius at AUS-e-TUTE: http://www.ausetute.com.au/trendar.html

Number of elements in period 2

Question: Give the number of elements in period 2 of the periodic table
Answer: 8

The rows going from left to right across the Periodic Table are called Periods.
The periods are numbered from 1 at the top to 7 on the bottom.
The first period contains only 2 elements: hydrogen and helium.
The second period contains 8 elements: lithium, beryllium, boron, carbon, nitrogen, oxygen,  fluorine and neon.

Find out more about how the periodic table is arranged at http://www.ausetute.com.au/pertable.html

Find more about the elements making up Period 2 at http://www.ausetute.com.au/trendpd2.html

I.C.E., R.I.C.E and Equilibrium

Need to calculate an equilibrium constant, but, you haven't been given all the equilibrium concentrations?
Then you need an I.C.E. Table (also known as a R.I.C.E. Table, an ICE chart, a RICE chart), and you can find out all about that at AUS-e-TUTE's new tutorial:
http://www.ausetute.com.au/ricetable.html

Now, if you are an AUS-e-TUTE Member, not only can go to the great member's only tutorial, but you can also:

• play the R.I.C.E. game
• answer the R.I.C.E. test questions and get immediate feedback
• do the R.I.C.E. exam
• make a R.I.C.E. worksheet (if you are a Teacher Member)
• do a R.I.C.E. quiz (if you a student with a Class or School Group)

And if you still haven't joined AUS-e-TUTE, you can sign up right here !