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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: benjibob on October 16, 2019, 09:27:35 PM

Title: SAT Chemistry Subject Test facts
Post by: benjibob on October 16, 2019, 09:27:35 PM

How can I find out all the little facts that the first section of the SAT Subject Test covers? Is there a place with these kind of information?

Example:

What is a compound in glass? ---> SiO2
(This was multiple choice but I forgot the other possible answers)

Also, can someone help me with the precipitate colors of transition metal compounds because I am struggling with that a bit too.

Title: Re: SAT Chemistry Subject Test facts
Post by: INeedSerotonin on October 18, 2019, 01:23:11 PM

I'm just a beginner in chemistry, but in my country there is this test which looks very much like the SAT, so perhaps I can help you somehow.

These facts are usually shown in an inorganic chemistry book. The compounds of glass (which is related to sand), the compounds of granite (which is not homogeneous), and the compounds of cement are important to know.

The structural formula of SiO2 is important to know too. It is certainly not just O = Si = O. It looks like this:

(https://sc02.alicdn.com/kf/HTB1UGHjKFXXXXXlXVXXq6xXFXXX1/High-Purity-Silicon-Dioxide-SiO2-5N-99.jpg_350x350.jpg)

As for the precipitate colors, what exactly are you struggling with?

Title: Re: SAT Chemistry Subject Test facts
Post by: AWK on October 18, 2019, 03:14:14 PM

Rings containing 4 silicon and oxygen atoms are very rare in a glass. Unfortunately, also for quartz, such schematic drawings are given as did INeedSerotonin. (https://www.researchgate.net/publication/272741300/figure/fig12/AS:273726713364499@1442272942565/Schematic-of-structure-of-SiO2-A-glass-and-B-crystal.png). From what it follows - well, projections of the structure on the plane are interpreted as real structures. This can be seen in the attached drawing, where the projection of the structure is rotated by a small angle to show the fifth and sixth atom in the SiO₂ ring (https://www.google.com/imgres?imgurl=https%3A%2F%2Fae01.alicdn.com%2Fkf%2FHTB1sJa7JFXXXXbgXXXXq6xXFXXXE%2FSiO2-Crystal-structure-model-23mm-series-silicon-dioxide-Covalent-Crystal-molecoular-model-Chemistry-Teaching-Model.jpg&imgrefurl=https%3A%2F%2Fwww.aliexpress.com%2Fitem%2F32658544341.html&docid=Ba4QpLp4mzQ1RM&tbnid=j1mgyNwhwWoz2M%3A&vet=10ahUKEwiI4qayq6blAhXPdJoKHQjjDekQMwhsKBkwGQ..i&w=600&h=600&bih=750&biw=1536&q=SiO2%20crystal%20structure&ved=0ahUKEwiI4qayq6blAhXPdJoKHQjjDekQMwhsKBkwGQ&iact=mrc&uact=8).

Title: Re: SAT Chemistry Subject Test facts
Post by: Enthalpy on October 21, 2019, 02:17:59 PM

Silica is SiO₂. Glass is more complicated and it contains other elements in big amount.
https://en.wikipedia.org/wiki/Glass

Some crystal structures of silica there
https://en.wikipedia.org/wiki/Silicon_dioxide
where stishovite and seifertite show silicon atoms with 6 bonds and oxygen with 3, nothing rare in solids.