4. Which safety precaution is recommended when a liquid is being heated in a test tube? A) When holding the test tube, keep fingers closest to the open end of the tube. B) Direct the flame of the burner into the open end of the test tube. C) Stopper the test tube with a rubber stopper. D) Wear goggles and a laboratory apron. 5. Base your answer on the diagram below and on your knowledge of biology.
Which statement describes two unsafe laboratory practices represented in the diagram? A) The flame is too high and the test tube is opened. B) The opening of the test tube is pointed toward the student and the student is not wearing goggles. C) The test tube is unstoppered and the student is not wearing goggles. D) The beaker has water in it and the flame is under the tripod. 2. Which safety precaution is recommended when a liquid is being heated in a test tube? A) Wear goggles and a laboratory apron. B) Direct the flame of the burner into the open end of the test tube. C) Stopper the test tube with a rubber stopper. D) Goggles and a laboratory apron do not need to be worn 3. Chlorophyll can be removed from leaves by boiling them in alcohol, a flammable solvent. In addition to wearing safety goggles, which is the safest procedure to follow? A) A stoppered test tube of leaves and alcohol should be held over a Bunsen burner. B) A stoppered test tube of leaves and alcohol should be placed into a beaker of alcohol on a tripod over a Bunsen burner. C) A beaker of leaves and alcohol should be placed on a tripod over a Bunsen burner. D) A beaker of leaves and alcohol should be placed into a larger beaker of water and heated on a hot plate.
Which statement describes two unsafe laboratory practices represented in the diagram? A) The flame is too high and the test tube is unstoppered. B) The opening of the test tube is pointed toward the student and the student is not wearing goggles. C) The test