pK

You've probably heard of pH, maybe even pOH, but what is pK?
Does this sound like brand of chewing gum to you?
Or does that "p" mean something?
Time to find out, with AUS-e-TUTE's new pK resources!

https://www.ausetute.com.au/pk.html

What is the pH of a Strong Base After You Dilute It?

The problem with strong bases like sodium hydroxide and potassium hydroxide are that they absorb moisture from the air making it difficult to accurately weigh them. So we rely heavily on obtaining an accurately known concentration for an aqueous solution of a strong base (using titration techniques for example) and then diluting this stock solution to produce new, dilute solutions of known concentration and pH.
When you dilute an aqueous solution of a strong base :

• hydroxide ion concentration decreases (towards 10^-7 M)
• pOH increases (towards 7)
• hydrogen ion concentration increases (towards 10^-7 M)
• pH decreases (towards 7)

Visit AUS-e-TUTE's new tutorial to understand why, then log-in to the Members ONLY area to play the game, answer test and exam questions (which give you instant feedback), take the quiz, or, just for teachers, you could make a printable worksheet or quiz.

International Year of the Periodic Table

It's 2019, and, the Periodic Table of the Elements is officially 150 years old.

The United Nations General Assembly and UNESCO (United Nations Educational, Scientific and Cultural Organization) has proclaimed 2019 as the International Year of the Periodic Table.
Look at activities, or register your own activity at https://www.iypt2019.org/

And you can download a free copy of the most recent periodic table (last updated 1^st December 2018) here

Mass Spectroscopy and Organic Molecules

What happens when an organic chemist makes a new molecule?
How do they know what the structure of the new molecule is?
They use lots of different techniques to determine the molecular mass and structure of the new molecule, one of which is mass spectroscopy.
Mass spectroscopy tells you the molecular mass of the molecule, and, it gives a good indication of how the atoms making up the molecule are put together. And it does this by breaking the molecule up!
Find out more about how mass spectroscopy can be used to determine the structure of organic molecules in our tutorial
AUS-e-TUTE Members can log-in to play the corresponding game, and to answer test and exam questions (which give you immediate feedback about your answer)

pH of Weak Acid After Dilution

What happens to the pH of a solution of weak acid, such as acetic acid, if you dilute it by adding water to it?
How much water would you have to add to 100 mL of 0.20 mol L^-1 acetic acid in order to make a solution with a pH of 3.0 ?
What is the pH of 1 × 10^-11 mol L^-1 acetic acid?
AUS-e-TUTE can help you answer these questions with our new resources.
AUS-TUTE Members should log-in to access the new "pH of Weak Acid After Dilution" tutorial, game and test (with worked solutions).
A "free-to-view" tutorial is currently available for non-members at:
https://www.ausetute.com.au/phdilwa.html

pH after mixing acid and base

If you add enough strong base to a strong acid you can neutralise the solution and its pH will be 7.
But what if you don't add enough base to the acid.
Will the solution be neutral?
Will the pH of the solution be 7?
These are all very good questions which is why AUS-e-TUTE has just added a new tutorial, game, test and exam on this topic.
AUS-e-TUTE Members should log-in to use these resources.

If you are not an AUS-e-TUTE Member yet, you can view the tutorial for free at https://www.ausetute.com.au/phmixsab.html

Effect of Dilution on pH of Strong Acid Solution

Need to know what the pH of your hydrochloric acid is after you dilute it?
Need to know how much water to add to your hydrochloric acid to make a solution with a particular pH?
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you with this.
AUS-e-TUTE members should log-in to use the new resources.
If you're not an AUS-e-TUTE Member, there is a "free-to-view" tutorial currently available at https://www.ausetute.com.au/phdilsa.html