Personal Protective Equipment (PPE) is the last line of defence and the least preferred option. Instead of going straight for a dust mask or respirator as a first choice the other control measures for ensuring that little or none of the chemical escapes should first be considered.
In a school or college, using PPE usually means wearing gloves (of the correct material for the substances being handled), eye-protection, labcoat and possibly dust masks or respirators.
The use of PPE, sometimes with a fume cupboard, as the principal means of control in practice is acceptable for virtually all school, or non-advanced FE, laboratory work. This is because normally only well tried, reasonably predictable methods are used and on a fairly small scale.
The articles below give details about various different types of PPE. The most important of which are probably eye protection and gloves.
In brief, to protect your eyes you have a choice of safety glasses or goggles. While many chemicals will do no more than irritate a little at most if splashed in the eyes, SSERC recommends that indirect-vent, chemical resistant goggles (BS EN166 3) should be worn when using anything of Acute Toxin Category 3 or above or anything corrosive, rather than irritant. The entries on individual chemicals will let you know at what concentrations individual chemicals gain/lose these classifications.
As for gloves, it is important to realise that no one glove material is resistant to all solvents and chemicals. Poorly fitting gloves may impair manipulative skills. Wearing unsuitable gloves is more dangerous than wearing no gloves at all. At least a person not wearing gloves knows that he or she has no protection and may exercise more care with their handling techniques. Note that even a pin-prick in a glove may lead to intimate skin contact with corrosive or irritating chemicals. Damage may then be done before the person has any sensation as to their exposure.