Bear in mind that your in-class practical work can be examined.
For example, a question might say that "during your studies, you carried out a first-hand investigation on BLAH" and then ask details about it. In school assessments, they will know what the actual experiment was. In the HSC, they won't. However, examiner's reports of past HSCs have complained about students giving answers that can't possibly be true. This can happen if the experiment described is impossible or involves materials that would not or can not be used in a school.
One specific case asked about an investigation of an alkene with bromine water, and asked for the name and structure of the alkene and to describe the observations. A common answer was ethene or ethylene which (a) would not be used in a school setting and (b) is a gas but the observations described the alkene as a liquid. In other words, students knew what the results for a liquid alkene (like cyclohexene) were but did not know that they were talking about a gas.
If you were asked to describe an investigation looking at a variety of metals and their properties in acid, claiming to have used sodium metal, or gold, or 18 M sulfuric acid will lead to mark deductions as they are not plausible materials to use in a high school lab.
Similarly, if asked about a galvanic cell involving two metals each in solutions of their salts, things like Zn in Zn(NO3)2 or Cu in CuSO4 are reasonable, but an electrode made of sodium or gold or a solution of platinum(II) nitrate would not be plausible.