can i use chalk as a substitite for calcium carbonate ?
No, this would be a bad idea. Limestone and marble are calcium carbonate. Chalk and dolomite in the wild are made of Calcium carbonate and calcium magnesium carbonate. They react with acid to give you bubbles of carbon dioxide. However, chalk processed for use on blackboards or chalkboards is NOT the same. It is usually made from Calcium sulfate di-hydrate, the soft mineral gypsum. So check your chalk with vinegar or dilute HCl first. If it does not fizz, it is not a carbonate chalk.
It's the same substance if. I remember correctly
Yes - chalk *is* calcium carbonate. If you need a very pure sample, it may not be what you need.
