Part B 1. Using a graduated cylinder, measure 20 cm3 2. Measure the mass using a mass balance.
of vinegar and pour into a larger sealable plastic bag.
3. Measure out 5 g of baking soda using a mass balance. Wrap the baking soda in a small sheet of tissue paper.
4. Measure the mass of the tissue paper containing the baking soda using a mass balance.
5. Calculate the mass of the tissue paper and the baking soda plus the mass of the vinegar and the sealable bag. Record the total mass.
6. Drop the tissue paper into the bag of vinegar and seal it quickly. 7. Once the reaction has stopped, find the mass of the bag.
j Go to page 40 of your Experimental Investigations Log to write up this investigation.
Summary questions 1. Explain the difference between a chemical change and a physical change.
2. Classify the following as either physical or chemical changes: Physical or chemical change?
Burning magnesium ribbon
Using sandpaper to smooth down a surface Melting chocolate Chopping wood Squeezing an orange Blowing up a balloon Switching on a torch A candle burning A candle melting
3. What signs of a chemical reaction would you observe during the following changes? a. Frying an egg b. Fireworks exploding c. An indigestion tablet being added to water d. A candle burning e. Milk souring
4. What is the law of conservation of mass?
5. A 2 g sample of solid iodine is placed in a tube and the tube is sealed after all the air is removed, as shown in Fig. 15.9. The tube and the solid iodine together weigh 30 g. The iodine will sublime (change state from solid to gas) in the tube on heating. Will the mass of the tube increase, decrease or stay the same? Explain your answer.