Question

question 3 12.5 pts which of the following statements is correct with respect to personal safety in the laboratory? be sure to bring marshmallows to lab for post lab smores. it is not important to note the direction of test tubes mouth while heating. tie back long hair when working with an open flame. safety glasses must be worn only when working with an open flame. question 4 12.5 pts you are heating a piece of glass and now want to pick it up. you should: use tongs use a rag or paper towels pour cold water on it pick up the end that looks cooler

Explanation:

Question 3

• Bringing marshmallows for post - lab s'mores is not appropriate lab behavior as food is not allowed in labs for safety and hygiene reasons.
• Test tube direction is important when heating to prevent accidents (e.g., chemicals from splashing towards you), so the statement saying it's not important is wrong.
• Tying back long hair in the lab is a standard safety practice to prevent hair from catching fire or getting caught in equipment.
• Safety glasses should be worn whenever there is a risk of eye injury, not just with open flames (e.g., with chemicals, flying debris), so that statement is wrong.

• Using a rag or paper towel to pick up hot glass is dangerous as they can catch fire or transfer heat, burning you.
• Pouring cold water on hot glass can cause it to crack due to thermal shock.
• Picking up the end that looks cooler is unreliable as the glass can still be hot enough to burn you.
• Using tongs is the proper way to handle hot glass as it keeps your hands away from the heat and provides a secure grip.

Answer:

C. Tie back long hair when working with an open flame.

Question 4