GCSE chemistry ISA help

[dwfan3]

my science teacher has set a practice ISA as homework however my teacher never really ran through it in class clearly so I seem to be stuck on the first question. I know it's just a practice one but the real test is worth 25% of my end of year GCSE grade in science and I would really like to do well. I have asked some of my peers for help but they're all in the same situation as me

 

(also could any of you please clarify what a 'preliminary investigation' is in science and what it's for because I'm not entirely sure as to what it is, my teacher never told anyone about it...)

 

If any of you think you can help I'd really appreciate if you could answer as soon as possible

 

Hypothesis:

The amount of carbonate in an ore sample can be measured by adding hydrochloric acid to the sample until it stops fizzing.

 

Question:

Describe briefly how you would carry out a preliminary investigation to find suitable values to use for this investigation.

Explain how the results of this preliminary work will help you to decide on the best range for the independent variable and the values of the control variables.

[studiot]

Do you not have any ideas?

 

What do you think the important variables are?

 

What do you think might interfere with the test?

What metals are on your list as having carbonate ores?

Edited September 21, 2013 by studiot