Question 29
In Activity 7E, 5 g of sodium hydrogen carbonate is gently heated in a test tube. A delivery tube carries the gas into limewater. The solid is heated for at least two minutes. Work in groups of four under teacher supervision. Wear safety goggles and suitable gloves. Secure the apparatus, keep the delivery tube unblocked and point tubes away from people. Remove the delivery tube from limewater before stopping heating to prevent suck-back. Handle cobalt chloride paper with gloves/tongs and dispose of it as instructed by the teacher. Identify any risks when doing this investigation. Write them down.
